Quetiapine treatment reses depressivelike behavior and reduces DNA activity induced by maternal deprivation

(1)

ContentslistsavailableatScienceDirect

Behavioural

Brain

Research

j o ur na l h o me p a g e :w w w . e l s e v i e r . c o m / l o c a t e / b b r

Research

report

Quetiapine

treatment

reverses

depressive-like

behavior

and

reduces

DNA

methyltransferase

activity

induced

by

maternal

deprivation

Zuleide

M. Ignácio

a,f

,

Gislaine

Z. Réus

a,∗

,

Helena

M. Abelaira

a

,

Amanda

L. Maciel

a

,

Airam

B. de

Moura

a

_,

_Danyela

_Matos

a

_,

_Júlia

_P.

_Demo

a

_,

_Júlia

_B.I.

_da

_Silva

a

_,

Fernanda

F. Gava

a,b

,

Samira

S. Valvassori

a,b

,

André

F. Carvalho

g

,

João

Quevedo

a,c,d,e

a_Laboratory_of_{Neurosciences,}_Graduate_Program_in_Health_Sciences,_Health_Sciences_Unit,_University_of_Southern_Santa_Catarina,_Criciúma,_SC,_Brazil b_Laboratory_of_Neural_Signaling_and_{Psychopharmacology,}_Graduate_Program_in_Health_Sciences,_Health_Sciences_Unit,_University_of_Southern_Santa

Catarina(UNESC),Criciúma,SC,Brazil

c_Center_for_{Translational}_Psychiatry,_Department_of_Psychiatry_and_Behavioral_Sciences,_Medical_School,_The_University_of_Texas_Health_Science_Center_at

Houston,Houston,TX,USA

d_Center_of_Excellence_on_Mood_Disorders,_Department_of_Psychiatry_and_Behavioral_Sciences,_Medical_School,_The_University_of_Texas_Health_Science_Center

atHouston,Houston,TX,USA

e_Neuroscience_Graduate_Program,_Graduate_School_of_Biomedical_Sciences,_The_University_of_Texas_Health_Science_Center_at_Houston,_Houston,_TX,_USA f_Laboratory_of_Physiology,_Pharmacology_and_{Psychopathology,}_Campus_Chapecó,_Federal_University_of_South_Frontier,_Chapecó,_Santa_Catarina,_Brazil g_Department_of_Clinical_Medicine_and_{Translational}_Psychiatry_Research_Group,_Faculty_of_Medicine,_Federal_University_of_Ceará,_Fortaleza,_CE,_Brazil

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received5November2016 Receivedinrevisedform 22November2016 Accepted25November2016 Availableonline29November2016

Keywords:

Quetiapine Epigenetic Antidepressant Maternaldeprivation Majordepressivedisorder

a

b

s

t

r

a

c

t

Stressinearlylifehasbeenappointedasanimportantphenomenonintheonsetofdepressionandpoor responsetotreatmentwithclassicalantidepressants.Furthermore,childhoodtraumatriggersepigenetic changes,whichareassociatedwiththepathophysiologyofmajordepressivedisorder(MDD). Treat-mentwithatypicalantipsychoticssuchasquetiapine,exertstherapeuticeffectforMDDpatientsand inducesepigeneticchanges.Thisstudyaimedtoanalyzetheeffectofchronictreatmentwithquetiapine (20mg/kg)ondepressive-likebehaviorofratssubmittedtomaternaldeprivation(MD),aswellasthe activityofhistoneacetylationbytheenzymeshistoneacetyltransferases(HAT)anddeacetylases(HDAC) andDNAmethylation,throughDNAmethyltransferaseenzyme(DNMT)intheprefrontalcortex(PFC), nucleusaccumbens(NAc)andhippocampus.Maternallydeprivedratshadadepressive-likebehaviorin theforcedswimmingtestandanincreaseintheHDACandDNMTactivitiesinthehippocampusand NAc.Treatmentwithquetiapinereverseddepressive-likebehaviorandreducedtheDNMTactivityin thehippocampus.Thisisthefirststudytoshowtheantidepressant-likeeffectofquetiapineinanimals subjectedtoMDandaprotectiveeffectbyquetiapineinreducingepigeneticchangesinducedbystress inearlylife.TheseresultsreinforceanimportantroleofquetiapineastherapyforMDD.

1. Introduction

Awidevarietyofresearchshowsthatthepathophysiologyof MDDinvolvesseveralbiologicalmechanismsboth,inthecentral nervoussystemandotherphysiologicalsystems[64].Thelow ther-apeuticresponsesofclassicalantidepressantssuggestthatMDDis anetiologicallyheterogeneousdisorder[21].Amongthevarious biologicalandpsychosocialfactors,stressduringchildhoodhistory, suchassexualabuse,physicalneglectandfamilyviolencewere

cor-∗ Correspondingauthorat:LaboratoryofNeurosciences,UniversityofSouthern SantaCatarinaCriciuma,SC,88806-000,Brazil.

E-mailaddress:gislainezilli@hotmail.com(G.Z.Réus).

relatedwithahighervulnerabilitytoMDDandanxietyinadulthood

[14,65].In addition,childhood traumahasalsobeenassociated

withpoorresponsetotreatment,similarlytotreatment-resistant depression(TRD)[41].Stressinchildhoodinduceschangesinthe hypothalamicpituitaryadrenal(HPA)axisactivity[6,22],aclassic physiologicalphenomenonassociatedtostress[63].Studieshave shownthatchangesinHPAaxisfunctionarefoundinMDD indi-vidualswhohaveexperiencedearlylifestress[1,54].

Despite the changes in theHPA axis functions,which seem inherentorinterrelatedtootherphysiologicalchanges,researches haveaddedanintensefocusonepigeneticphenomenaintricate in the processes that occuralong or much later in individuals exposed tostressat thebeginning oflife.Amongother mecha-nisms,epigeneticincludesprocesses,whicharebetterknownand

(2)

sistsof acetylation oflysine residues. Thisprocess reducesthe affinitybetweenproteinsandDNA,promotingarelaxationofthe chromatinstructureandalsoincreasingtherecruitment, activa-tionandstabilizationofthetranscriptionalmachinery[37].The acetylationlevelsalong ofthechromatinaredeterminedbythe balancebetweenHAT,whichaddsacetylgroups,andHDAC,which removesacetylgroupsfromlysineresiduesinhistone[30].The his-toneacetylationlevelisdeterminedbythebalancebetweenHAT andHDACenzymeactivity,andthusdeterminesthelevelof tran-scriptionofassociatedgene[29].Theresilience,aphenomenonof resistanceandabilitytocopewithadversitythroughoutlifecan beseriouslyimpairedwhenindividualsaresubjectedtotraumatic eventsduringcriticalperiodsforbraindevelopmental program-ming and can result in long-lasting detrimental consequences throughoutlifeandadulthood[34].Infact,recentliteraturehas pointedoutthatepigeneticchangesresultingfromstressin child-hoodareinherentinarepertoireofbiologicalprocessesinvolved indepression[12,34,58].Inhippocampusofsuicidevictims,who sufferedvariousformsof abuseandneglectinchildhood, stud-iesshowed increasedmethylation of gene promoter region for glucocorticoidreceptor(GR)in parallel witha reduction inthe GRmRNAlevelsandGRexpression[31,38].Thesefindings trans-lateresultsobtainedfromthe hippocampusofrat subjectedto maternaldeprivation,inwhichtheauthorsalsoobservedincreased depressive-likebehavior[67].OtherresearchersusingMD proto-cols,alsoobservedincreaseddepressive-likebehaviorsinparallel withincreaseofHDACactivityintheratNAc[48].Itisimportant tonotethattheincreaseinDNAmethylationanddepressive-like behaviorswerereversed withHDACinhibitors[67].Indeed,the inactivechromatinisassociatedwithmethylatedDNA[59],which supportsthefindingsaboutcorrelationbetweeninhibitionofHDAC andreversingofDNAmethylationanddepressivebehavior.Some studieshaveshownthatclassicalantidepressants,aswellas fast-actingdrugsseemtoreversetheepigeneticalterationsinvolvedin previousstressinchildhood,inanimalssubjectedtoMD[48].

Atypicalantipsychotic, also has epigenetic effects by reduc-ing the methylation of genes in the central nervous system

[19,20], and peripherally [23]. The Food and Drug

Administra-tion (FDA) approved quetiapine in 1997 for the treatment of schizophrenia [9]. Several studies have demonstrated the effi-cacy, safety, and tolerability of quetiapine in the treatment of MDD and bipolardisorders [3,56]. Noteworthy is thefact that TRDpatientsshowedantidepressantresponseswhentreatedwith quetiapine[13].Moreover,inanimalssubjectedtochronicstress, quetiapine,unlikefluoxetineaclassicalantidepressant,reversed depressive-likebehaviorandimprovedhippocampal neurogene-sis[66].Quetiapinehasserotonergicpropertiesasa5-HT1Apartial

agonist,potent ␣1 and ␣2-adrenoceptorsantagonist, as also is

an inhibitor of the norepinephrine transporter, through its N-desalkylquetiapinemetabolite[50,60].Theseaminergicactionsare believedtoplaya roleinitsantidepressantproperties[27] and increasethe therapeuticeffectof classical antidepressants[10]. Therefore,thestudyof drugstargeting neuroepigenetic mecha-nismscouldnotonlyprovideinsightsintotheunderstandingof themechanismsunderlyingneurobiologicalcausesoftheMDD, butshouldalsoacceleratethedevelopmentofnovel pharmacolog-icalagentswhichcanbemosteffectiveinthetreatmentofMDD.

Pregnant female Wistar rats (age of 3 months, weight of 250–280g)wereobtainedfromthebreedingcolonyof Universi-dadedoExtremoSulCatarinense(UNESC,Criciúma,SC,Brazil)and werehousedforoneweekinthepresenceofmalesforsexual expe-rience.Attheendof 7days,pregnantrats(n=10)werehoused individuallywithadlibitumaccesstofoodandwater.All moth-ersandpupswerekeptona12hlight/darkcycle(06:00a.m.to 06:00p.m.)atatemperatureof23±1◦_C,_including_the_pups

sub-jectedtoMD.Maleandfemalepupswereusedduringthematernal deprivationperiod,butonlyhalfofmaleweresubjectedto depri-vation,accordingtotheprotocolbelow andschematic drawing (Fig.1).We takecaretoselectfemales withapproximatelythe samenumberofanimals,sothatthenumberofanimalsinthe sep-arationofthelitterwasnotmuch differentbetweenthem.The wholelitter,andthemotherratwerehousedinacleanbox,only afterthelastdayoftheMDprotocol.Afterthis,theanimalswere weanedinthe21thpostnataldayandhousedwithfiveanimalsper cage.FemalesweredonatedtotheUNESCvivariumforother stud-ies.Onlymaleratswereusedinthisresearchandwereprimarily dividedintotwoexperimentalgroups:(1)control,non-deprived (n=23),which receivednotreatmentwhatsoever; (2)deprived (n=21),whichweresubmittedtoMDasdescribed.All experimen-talproceduresinvolvinganimalswereperformedinaccordance withtheNIHGuidefortheCareandUseofLaboratoryAnimalsand theBrazilianSocietyforNeuroscienceandBehavior(SBNeC) rec-ommendationsforanimalcareandwithapprovalbylocalEthics Committeeunderprotocolnumber82/2012.

2.2. Maternaldeprivation(MD)protocol

Thepupsweredeprivedofthemotherfor3hperdayduringthe first10postnataldays(seeFig.1).Inthefirstpostnatalday,theMD protocolwasappliedto50%ofthemalepupsduring1–10postnatal days;othermaleswereusedascontrol.Themalepupswere ran-domlyselectedandafterthefirstwithdrawalprotocol,deprived pupsweremarkedforthedeprivationprotocolsinthefollowing days.Thematernaldeprivationprotocolconsistedofremovingthe pupsfromthenextbox.Non-deprivedanimalsremainundisturbed inahomecagewiththeirmother.

2.3. Drugsandexperimentaldesign

(3)

Fig.1.SchematicdrawingoftheMDprotocolandchronictreatmentwithquetiapine(14days;20mg/kg).MDprocedureswereperformedfor10daysafterthefirstpostnatal day.Thebehavioraltests(open-fieldandforcedswimming)wereperformedat62ndand63rdpostnataldays.Afterthebehavioraltestbrainsampleswereassessedtothe biochemicalanalysis.

reached 50th postnatal day, the drug treatment was initiated (seeFig.1).Theanimalsweredividedintofourgroups:(1) non-deprived+saline(n=11); (2) non-deprived+quetiapine (n=12); (3)deprived+saline(n=10);and(4)deprived+quetiapine(n=11).

2.4. Behavioraltests

All behavioral tests were conducted in the morning (8:00 a.m.–12:00p.m.),60minafterdrugtreatment,accordingtothe pro-tocolsdescribedinthemethodssection.Allbehavioraltestswere performedbyanobserverblindtotheexperimentalgroups.

2.4.1. Openfieldtest

Onthe62ndpostnatalday(Fig.1),and60minafter adminis-trationofquetiapineorsaline,theanimalsweresubjectedtothe open-fieldapparatus,in ordertoassesspossibleeffects ofdrug treatmentonspontaneouslocomotoractivity.Analysisoftherat’s spontaneousactivitywascarriedoutinanopenfieldapparatus, whichisanarena45×60cmsurroundedby50cmhighwallsmade ofbrownplywoodwithafront-facingglasswall.Thefloorofthe openfieldwasdividedinto9rectangles(15×20cmeach)byblack lines.Animalsweregentlyplacedontheleftrearrectangleandleft toexplorethearenafor5min.Thenumbersofhorizontal (cross-ing)andvertical(rearing)activitiesperformedbyeachratduring the 5min observationperiod were counted by an experienced observer.

2.4.2. Forcedswimmingtest

Theforcedswimmingtestwasconductedaccordingtothe previ-ousreports[42,45].Thetestinvolvestwoindividualexposurestoa cylindricaltankfilledwithwaterinwhichtheratscannottouchthe bottomofthetankorescape.Thetankismadeoftransparent Plexi-glas,80cmtall,30cmindiameter,andfilledwithwater(22–23◦_C)

toa depthof 40cm. On the62thpostnatalday(Fig.1), 60min afterthequetiapineorsalinetreatment,andafterthelocomotor activitytestintheopenfield,theratswereindividuallyplacedin thecylindercontainingwaterfor15min(pre-testsession).Onthe 63rdpostnatalday(Fig.1),theratsreceivedtheirtreatment,and after60minwereagainsubjectedtotheforcedswimmingtestfor asessionof5min(testsession).Theimmobilitytimeoftherats wasrecordedinsecondsbyanexpertobserver(theresearcherwas blindtotheexperimentalgroups).Afterthebehavioraltests,all ratswerekilledbydecapitationandthebrainswereimmediately removed.ThePFC,hippocampusandNAcwerequicklyand man-uallyisolatedbyaskilledresearcher,usingamagnifyingglass,a spatulaandathinbrush.Thedissectionwasbasedonthe histo-logicaldistinctionsdescribedbyPaxinosandWatson[43].After theremovalofthestructures,theywereplacedinEppendorftube andstoredinafreezerat−80◦_C_for_posterior_biochemical

analy-sis.Thebraintissueswereusedforanalysisofhistoneacetylation

andDNAmethylationlevelsbyobservingtheenzymaticactivityof HAT,HDACDNMT.

2.5. Histoneacetylatase,histonedesacetylaseandDNA methyltransferaseactivities

2.5.1. Nuclearextractionandcytosolicfractionseparation

ThePFC,hippocampusandNAcwererapidlyfrozenandstored at−80◦Cuntilnuclearproteinswereextracted.Thetissue sam-ples,PFC,hippocampusandNAc,frozenat−80◦_C,_were_subjected

to a nuclear extraction protocol from a Nuclear Extraction kit (Sigma,StLouis,USA).Briefly,sampleswerehomogenizedin cyto-plasmiclysisbuffercontainingdithiothreitol(DTT)andprotease inhibitors.Thesuspensionwaskeptonicefor15minandthen cen-trifugedat250xgfor5minat4◦_C._The_supernatant_containing_the

cytosolicfractionwasdiscarded,andthepelletwasresuspendedin twovolumesofcoldcytoplasmiclysisbuffer.Thesuspensionwas homogenizedusingasyringewithasmallgaugeneedleand cen-trifugedat8000xgfor20minat4◦_C._The_pellet_was_resuspended

inanextractionbuffercontainingDTTandproteaseinhibitors.The resultingsamplewaskeptinslowagitationfor30–60mininan orbitalshakerat4◦_C._After,_the_nuclear_suspension_was_centrifuged

at16,000xgfor5minat4◦_C_and_the_supernatant_containing_the

nuclearextractwastransferredtoanothertubeandstoredat−80◦_C

untilfurtheranalysis.

NuclearextractsfromthePFC,hippocampusandNAcwere sub-jectedtotheHDAC,HATandDNMTenzymaticactivityassay(n=5 foreachbrainregionandenzyme)withtheuseofHDAC,HATand DNMTAssaykits(ColorimetricDetection)accordingtothe manu-facturer’sinstructions.Briefly,nuclearextractsamplesweremixed withHDAC(EPIGENTEK;Basecatalog#P-4034),HAT(EPIGENTEK; Base catalog #P-4003)or DNMT (EPIGENTEK;Base catalog #P-3009)assaybuffer,moreassaysubstrateofthesameenzymes,in a96wellplateandincubatedat30◦_C_for₄₅_min._{Concomitantly,}_a

standardcurvewasperformedwithserialdilutionsofHDAC,HAT orDNMTsubstrates,asalsopositiveandnegativecontrolswere addedtotheplate.Afterwards,thedevelopersolutionwasadded tothewells,andtheplatewasincubatedatroomtemperaturefor 15min.Acolorimetricreadingwasperformedonafluorescence platereaderwith450nmforHDAC,HATandDNMTactivities.

2.6. Statisticalanalysis

(4)

quetiapine,asmeasuredbyimmobilitytime(Fig.2a;F(1–41)=9.047,

p<0.001).Fig.2bshowstheeffectsofMDandquetiapineonthe locomotor activity evaluated in the open-field test. Locomotor activitywasnotdifferentbetweenMDandcontrolanimals (non-MD),asmeasuredbynumberofcrossingsandrearings.However, quetiapinereducedlocomotoractivityinMDandcontrolanimals (non-MD),butonlywhencomparedtosaline-treatedMDanimals, asmeasuredbycrossings(Fig.2b;F(3–40)=3.72;p<0.05)and

rear-ings(Fig.2b;F(3–40)=5.89;p<0.01).

3.2. Measurementofepigeneticparameters

3.2.1. Histonedeacetylases(HDAC)activity

Fig.3aillustratestheinfluenceofMDandchronicquetiapine treatmentontheHDACactivity.Thestatisticalanalysisrevealed thatadulthoodMDratsdisplayedanincreaseintheHDAC activ-ityinthehippocampus(Fig.3a;F(3–16)=11.11;p<0.001)andNAc

(Fig. 3a;F(3–16)=13.81;p<0.001), but it didnot changein PFC

(Fig.3a;F(3–16)=1.61;p=0.227).However,chronictreatmentwith

quetiapinedidnotreducesignificantlytheincreaseofHDAC activ-ityinMDanimals.

3.2.2. Histoneacetyltransferases(HAT)activity

AsdepictedinFig.3b,thestresscausedbyMDdidnotinduce alterationofHATactivityinadultanimals.Similarly,chronic treat-mentwithquetiapinedidnotcauseanychangeintheHATactivity, whetherin relationtoMD animalstreated withsaline or con-trolanimals(non-MD).Statisticalanalysisrevealednosignificant changesinanyofbrainareas:Hippocampus(Fig.3b;F(3–16)=0.22;

p=0.88),NAc (Fig.3b;F(3–16)=2.05;p=0.15), and PFC(Fig.3b;

F(3–16)=0.58;p=0.63).

3.2.3. DNAmethyltransferases(DNMT)activity

Fig.3cshowstheinfluenceofMDandchronicquetiapine treat-mentontheDNMTactivity.Thestatisticalanalysisrevealedthat adulthoodMDratsdisplayedanincreaseofDNMTactivityinthe hippocampus.MDanimalstreatedwithquetiapinealsoshowedan increaseinthehippocampalDNMTactivity,whencomparedto ani-malswithoutstress(non-MD).Thequetiapinesignificantlyreduced DNMTactivitywhencomparedtoMDanimalstreatedwithsaline, indicatingthatquetiapinehasapharmacologicalprofileinorder toreversethehippocampalDNAmethylationinstressedanimals (Fig.3c;F(3–16)=36.56;p<0.001).IntheNAc,theDNMTactivity

increasedsignificantlyinMDanimals,bothtreatedwithsalineand quetiapine(Fig.3c;F(3–16)=13.92;p<0.001).Thechronictreatment

withquetiapinedidnotreducesignificantlytheincreaseofDNMT activityintheNAcofMDanimals.InthePFC,onlyMDanimals treatedwithquetiapinehadanincreaseintheDNMTactivity com-paredtoanimalsnotstressed(non-MD)andtreatedwithsaline (Fig.3c;F(3–16)=3.62;p<0.05).Theothergroupsshowedno

signif-icantchangesinenzymeactivityinthePFC.

changesinducedbystressinearlylife.Similartootherstudies,the MDincreasedimmobilitytimeintheforcedswimmingtest, indi-catingadepressive-likebehaviorinanimals,andconfirmingthat thetraumaticexperiencesinearlylifecanculminateindepression inadulthood[49].Chronictreatmentwithquetiapinesignificantly reduceddepressive-likebehavior.Theantidepressant-likeeffects ofquetiapinewerealsodemonstratedinotherstudiesinwhich adultanimalsweresubjectedtochronicstress[66,17].Additionally, quetiapinereversedthereductionofGABAlevelsinthe hippocam-pusaswellasitreducedtheconcentrationsofcorticosteronein theserumofanimalssubjectedtostress[17].In thestudiesby Wangetal.[66],theauthorsobservedthatquetiapineexercised antidepressant-likeactioninrodentresistanttotreatmentwith flu-oxetine.Inthepresentstudy,quetiapineinducedasignificanteffect inanimalssubjectedtostressinearlylife,aconditionthathasbeen highlightedasapivotofthepoorresponsetoclassical antidepres-santtreatmentsinMDDpatients[41,68],andinanimalsdisplaying depressive-likebehaviors[70].Itwasobservedthatanimals sub-jectedtoMDexhibiteddepressive-likebehaviorinadulthood,and escitalopram,aselectiveserotoninreuptakeinhibitor(SSRI),was lesseffectiveinreversingthedepressive-likebehavior[70].These andotherstudy[17]revealedthatquetiapine,asmonotherapyand chronicallyadministered exerted significantantidepressant-like effect.InMDDpatients,someauthorsalsoshowedthatquetiapine, aloneandchronicallyadministered,exercisedsignificant antide-pressanteffects[35,5],aswellasitreducedanxietyinMDDpatients withcomorbidanxiety[18].Thus,quetiapine,inadditionto func-tionasadjunctivetherapywithotherantidepressantdrugs,also exertsantidepressanteffectwhenadministeredasmonotherapy.

In locomotor activitytest, quetiapine reduced crossings and rearing activities, when compared with deprived animals and saline-treated,a resultthat suggest a sedativefunctionof dose administered60minbeforetesting.Indeed,quetiapinehasquick sedativeeffectafteritsadministrationinMDDpatients[61],being oneofitslimitationsastherapyforMDD[8].However,theeffecton locomotoractivityshouldbeinterpretedwithsomecaution,given thatinourpilotstudy,onlytheconcentrationof80mg/kgexerted sedativeeffect,oneofthereasonsthatpromptedustochoosethe lowestconcentrationforthisstudy.Somestudieshaveobserved thatmaternallydeprivedrats,inthe9thand10thpostnataldays, presentedanincreaseinthelocomotoractivityinadolescence[36]

(5)

(a)

(b)

*

*/#

0 20 40 60 80 100 120 140 160 180

Immobility

Immobility time (s)

Control+Saline Control+Quetiapine Maternal Deprivation+Saline Maternal Deprivation+Quetiapine

#

0 10 20 30 40 50 60 70

Crossing

Rearing

Number of crossings and rearings

Fig.2.MDandquetiapine(20mg/kg,during14days)effectsontheimmobilitytimeintheforcedswimmingtest(2a)andlocomotoractivity(crossingsandrearingsnumbers) intheopenfield(2b).Valuesexpressedasthemeanandstandarderrorofthemean(M±SEM).*Differentfromcontrol+saline,p<0.05.#DifferentfromMD+saline,p<0,05.

byquetiapinetowardtheantidepressanttherapeutic,whenadded toclassicalantidepressantsorasmonotherapy[61].Other stud-ieshavefoundthatimipramine,aclassicantidepressant,reduced immobilityintheforcedswimmingtestindiabeticrats,whilealso reducedlocomotoractivityintheopenfield[7,40].Still, regard-ingtheeffects of locomotor activity,somestudiessuggest that reduction ofmotor activityin theopenfield is correlated with increasedimmobility,whereasotherauthorshaveshownthat loco-motor activityisnot underlyingtheperformance of animalsin theforced swimtest[11].Someauthorssuggestthatother fac-tors may be involved in motor behavior assessed in the open field.For example,in mice,themotoractivitywassignificantly decreasedbyimipraminechronicallyadministered,afterchronic stressfor27days,whiletheimmobilitytimealsowasreducedin theforcedswimtest.Ontheotherhand,after21daysofchronic stress,imipramine didnotchangelocomotoractivity,compared withthecontrolsorstressedanimals[71].

Althoughquetiapineactsthroughwidevarietyofmechanisms, anditisdifficulttoidentifythemechanismsmorecloselyrelated totheantidepressanteffect[51],itisimportanttonotethatthe drug increases the release of dopamine in brain regions such asPFC[46].Thisquetiapine effectissuggested asimportantto improveaffectiveandcognitiveeffectsunderlyingdepression[46]. Besidesdopamine,quetiapinemayalsohasatherapeuticbenefitto increaseextracellularlevelsofnorepinephrinethroughblockadeof 5-HT2Creceptors[2],whichexertatonic,inhibitoryinfluenceupon

dopaminergicandadrenergicpathwaysinthePFC[39].Blierand Blondeau[2]alsopostulatedthatMDD patientsnon-responsive toselectiveserotoninreuptakeinhibitors(SSRIs) mightbewith reduced noradrenergic activity, given that SSRIs reduces firing

of noradrenergic neurons in the locus coeruleus, by activating receptors 5-HT2A oninhibitory GABAergic neurons that

modu-latenoradrenergicneurons.Regardingthenoradrenergicactivity isimportanttonotethatquetiapinealsohasstrongblockingaction onthenorepinephrinetransporterandisapotent␣₂-adrenoceptor

antagonist[50,10],whosemechanismsincreasethesynaptic avail-abilityofnoradrenaline.Inadditiontothenoradrenergicactivity,it isalsoimportanttoconsiderthatincreasingdopaminergicactivity maybeamechanismrelatedtotherapeuticeffectonindividuals whohavepoorresponsetoothertreatments,assuggestedby[24].

4.2. EffectofMDandtreatmentwithquetiapineontheenzymatic activityofHDAC,HATandDNMT

Inthiswork,adultanimals,whichwerematernallydeprived, showedanincreaseinHDACandDNMTactivityinthe hippocam-pusandNAc,confirmingotherfindingsdescribed[67,48].Increased activityoftheseenzymesisassociatedwithlowergene

transcrip-tion [28,29]. Noteworthy is thefact that increasingfunction of

HDACsisassociatedwithdepressioninanimalmodelsandreduced therapeuticresponsetoantidepressants[15,62].Also,itis impor-tanttonotethatchronictreatmentwithantidepressantscanalter theepigeneticchanges[48,57],andtomitigatethelossesof hip-pocampalneurogenesispossiblyunderlyingtoepigeneticchanges resultingfromstressinearlylife[57].

(6)

(b)

(c)

0 0.01 0.02 0.03

PFC HIP NAc

HDAC activity μM/

0 0.02 0.04 0.06 0.08 0.1

PFC HIP NAc

HAT activity

mM/mg protein

HAT

*

*/#

_*

0 0.02 0.04 0.06 0.08 0.1

PFC HIP NAc

DNMT activity mM/mg protein

DNMT

Fig.3. MDandquetiapine(20mg/kg,during14days)effectsontheenzymeactivities:histonedeacetylase(HDAC)(3a),histoneacetyltransferase(HAT)(3b)andDNA methyltransferase(DNMT)(3c).Valuesexpressedasthemeanandstandarderrorofthemean(M±SEM).*Differentfromcontrol+saline,p<0.05.#DifferentfromMD+saline, p<0,05.

inthehippocampusandpromotedaslightreductioninenzymatic activityintheNAc.Somestudieshaveshownthatquetiapine,as wellasotherdibenzepinederivativessuchasclozapineand olan-zapinealsohasepigeneticeffect,reducingthemethylationofgenes inthecentralnervoussystem,unlikebutyrophenonederivative haloperidolandthepiperidyl-benzisoxazolederivativerisperidone

[19,20].Anotherimportantstudyfromhumanneuroblastomacell

cultureshowedthatquetiapinepromoteshypomethylationinwide varietyof genes,withthe mosthypomethylatedgenes belongs to promoter regions located within CpG island [55]. Another importantfindingof theselaststudieswasone decreased DNA methylationin thespecificCpG site onthepromoter regionof theserotonintransportergene(5-HTT).Geneticpolymorphismsin theseregions areassociatedwithincreasedmethylationof pro-moterregionsofthe5-HTTgeneinlymphoblasticcelllinesand withreduced transcriptionalactivityforthemRNAofserotonin transporter[44].Moreover,literaturereportsthatthepolymorphic variantassociatedwithlowertranscriptionalactivity,alsopresents greaterinteractionbetweengenexstressinearlylife,resulting

inlifelongdepression[25].Importantlyisthefactthatgenotype thatpresentreducedtranscriptionalactivityalsoisassociatedwith poorresponseofpatientstotreatmentwithclassical antidepres-sants[53].Anotherimportantevidenceis thatthepolymorphic variant,whichshowedahigherlevelofmethylationandlower tran-scriptionalactivity,wasalsoassociatedwithsmallerhippocampal volumeinMDDpatients[16].

(7)

leastinpart,berelatedtoitsabilitytoreducetheactivityofDNMT enzymes.

TheDNMTactivityincreasedinthePFCofMDanimalstreated withquetiapine.Thisresultseemsparadoxicalwhencomparedto theresultsobservedinthehippocampus,inthisstudyorresults fromstudies, which observed other brainregions. However, in studieswhich observed a reduction inDNA methylation inthe PFC, theresearch was directed tospecific promoter regions of genesassociatedwithotherdisorders,wherethemethylationand demethylationprocessesappeartorequireintermediationofother molecularmarkers[20].Asdiscussedbytheauthors,inneuronsthe promotermethylationisadynamicprocess,involvingmany fac-tors,amongwhichmaybethepsychopathologyandbrainregions involvedwithfunctionsrelevanttorespectivedisorder.In addi-tiontolackingdataaboutthefunctionofquetiapineonepigenetic parameters,thescientificliteraturealsolacksdatainvolvingthe profileof quetiapine and otheratypical antipsychotics onDNA methylationmechanismsinthePFC.Onestudyshowedthat cloza-pineandrisperidoneincreasedmethylationofsomegenes,while inothergenes,itappearstoshowreducedmethylationinthePFC, possiblyasapositiveantipsychoticeffectonbehaviorsrelatedto schizophrenia,orotherpsychiatricdisorders[52].Therefore, fur-therstudiesareneededinordertouncoverapossibleprotective orharmfulroleofquetiapineandotheratypicalantipsychoticsin epigeneticparametersinthePFC.

Inconclusion, theresultsofthis studyshowedthat quetiap-ineexertedantidepressant-likeeffectsinanimalssubjectedtoMD stress,aneventunderlyingtoMDD.Additionally,ratifyingresults ofthescientificliterature,thisworkdataalsoindicatethat previ-ouslifestressinducesalterationsinepigeneticpatterns,whichcan culminateinareductioningenetranscriptionprocess.Amost sig-nificantfindingwasthefactthatquetiapineinducedasignificant decreaseinDNMTactivityinthehippocampus,DNAmethylation mechanisms,possiblyreversinga hypermethylationinducedby stressinchildhood.

Acknowledgements

TheTranslationalPsychiatryProgram(USA)isfundedbythe DepartmentofPsychiatryandBehavioralSciences,McGovern Med-ical School, The University of Texas Health Science Center at Houston(UTHealth).LaboratoryofNeurosciences(Brazil)isone of thecenters of theNational Institutefor MolecularMedicine (INCT-MM)andoneofthemembersoftheCenterofExcellence inAppliedNeurosciencesofSantaCatarina(NENASC).Itsresearch issupportedbygrantsfromCNPq(JQ)FAPESC(JQ);Instituto Cére-broeMente(JQ)andUNESC(JQandGZR).JQandAFCare1ACNPq ResearchFellow.

References

[1]C.V.Baes,C.M.Martins,S.M.Tofoli,M.F.Juruena,Earlylifestressindepressive patients:HPAaxisresponsetoGRandMRagonist,Front.Psychiatry5(2014) 2.

[2]P.Blier,C.Blondeau,Neurobiologicalbasesandclinicalaspectsoftheuseof aripiprazoleintreatment-resistantmajordepressivedisorder,J.Affect. Disord.128(Suppl.1)(2011)S3–S10.

[3]B.T.Baune,Newdevelopmentsinthemanagementofmajordepressive disorderandgeneralizedanxietydisorder:roleofquetiapine,Neuropsychiatr. Dis.Treat.4(6)(2008)1181–1191.

[4]S.Boku,H.Toda,S.Nakagawa,A.Kato,T.Inoue,T.Koyama,N.Hiroi,I.Kusumi, Neonatalmaternalseparationaltersthecapacityofadultneuralprecursor cellstodifferentiateintoneuronsviamethylationofretinoicacidreceptor genepromoter,Biol.Psychiatry77(4)(2015)335–344.

[5]B.Bortnick,N.El-Khalili,M.Banov,D.Adson,C.Datto,S.Raines,W.Earley,H. Eriksson,Efficacyandtolerabilityofextendedreleasequetiapinefumarate (quetiapineXR)monotherapyinmajordepressivedisorder:a

placebo-controlled,randomizedstudy,J.Affect.Disord.128(1–2)(2011) 83–94.

[6]L.L.Carpenter,J.P.Carvalho,A.R.Tyrka,L.M.Wier,A.F.Mello,M.F.Mello,G.M. Anderson,C.W.Wilkinson,L.H.Price,Decreasedadrenocorticotropichormone andcortisolresponsestostressinhealthyadultsreportingsignificant childhoodmaltreatment,Biol.Psychiatry62(10)(2007)1080–1087. [7]L.B.Ceretta,G.Z.Réus,R.B.Stringari,K.F.Ribeiro,G.Zappellini,B.W.Aguiar,B.

Pfaffenseller,C.Lersh,F.Kapczinski,J.Quevedo,Imipraminetreatment reversesdepressive-likebehaviorinalloxan-diabeticrats,DiabetesMetab. Res.Rev.28(2)(2012)139–144.

[8]D.S.Cha,R.S.McIntyre,Treatment-emergentadverseeventsassociatedwith atypicalantipsychotics,Expert.Opin.Pharmacother.13(11)(2010) 1587–1598.

[9]S.M.Cheer,A.J.Wagstaff,Quetiapine−Areviewofitsuseinthemanagement ofschizophrenia,CNSDrugs18(3)(2004)173–199.

[10]O.Chernoloz,M.ElMansari,P.Blier,Effectsofsustainedadministrationof quetiapinealoneandincombinationwithaserotoninreuptakeinhibitoron norepinephrineandserotonintransmission,Neuropsychopharmacology37 (7)(2012)1717–1728.

[11]J.N.Crawley,J.K.Belknap,A.Collins,J.C.Crabbe,W.Frankel,N.Henderson,R.J. Hitzemann,S.C.Maxson,L.L.Miner,A.J.Silva,J.M.Wehner,A.Wynshaw-Boris, R.Paylor,Behavioralphenotypesofinbredmousestrains:implicationsand recommendationsformolecularstudies,Psychopharmacology(Berl.)132(2) (1997)107–124.

[12]V.S.Dalton,E.Kolshus,D.M.Mcloughlin,Epigeneticsanddepression:return oftherepressed,J.Affect.Disord.155(2014)1–12.

[13]E.J.Daly,M.H.Trivedi,Areviewofquetiapineincombinationwith antidepressanttherapyinpatientswithdepression,Neuropsychiatr.Dis. Treat.3(6)(2007)855–867.

[14]N.P.Daskalakis,R.C.Bagot,K.J.Parker,C.H.Vinkers,E.R.deKloet,Thethree-hit conceptofvulnerabilityandresilience:towardunderstandingadaptationto early-lifeadversityoutcome,Psychoneuroendocrinology38(9)(2013) 1858–1873.

[15]M.Dyrvig,H.H.Hansen,S.H.Christiansen,D.P.Woldbye,J.D.Mikkelsen,J. Lichota,EpigeneticregulationofArcandc-Fosinthehippocampusafteracute electroconvulsivestimulationintherat,BrainRes.Bull.88(5)(2012) 507–513.

[16]M.C.Eker,O.Kitis,H.Okur,O.D.Eker,E.Ozan,S.Isikli,N.Akarsu,A.S.Gonul, Smallerhippocampusvolumeisassociatedwithshortvariantof5-HTTLPR polymorphisminmedication-freemajordepressivedisorderpatients, Neuropsychobiology63(1)(2011)22–28.

[17]S.M.K.S.ElDine,AnincreaseinGABAcontentinHippocampusofAlbinorats exposedtochronicrestraintmodelandtreatedbyQuetiapinefor3weeks,J. Pharm.Innov.3(12)(2015)89–93.

[18]I.Galynker,A.Khan,Y.Grebchenko,A.Ten,L.Malaya,P.Yanowitch,L.J.Cohen, Low-doserisperidoneandquetiapineasmonotherapyforcomorbidanxiety anddepression,J.Clin.Psychiatry66(4)(2005)544.

[19]A.Guidotti,J.Auta,Y.Chen,J.M.Davis,E.Dong,D.P.Gavin,D.R.Grayson,F. Matrisciano,G.Pinna,R.Satta,R.P.Sharma,L.Tremolizzo,P.Tueting, EpigeneticGABAergictargetsinschizophreniaandbipolardisorder, Neuropharmacology60(7–8)(2011)1007–1016.

[20]A.Guidotti,D.R.Grayson,DNAmethylationanddemethylationastargetsfor antipsychotictherapy,DialoguesClin.Neurosci.16(3)(2014)419–429. [21]G.Hasler,Pathophysiologyofdepression:dowehaveanysolidevidenceof

interesttoclinicians?WorldPsychiatry9(3)(2010)155–161.

[22]C.Heim,D.J.Newport,S.Heit,Y.P.Graham,M.Wilcox,R.Bonsall,A.H.Miller, C.B.Nemeroff,Pituitary-adrenalandautonomicresponsestostressinwomen aftersexualandphysicalabuseinchildhood,JAMA284(5)(2000)592–597. [23]L.C.Houtepen,A.H.vanBergen,C.H.Vinkers,M.P.Boks,DNAmethylation

signaturesofmoodstabilizersandantipsychoticsinbipolardisorder, Epigenomics8(2)(2016)197–208.

[24]M.C.Hsiao,K.J.Lin,C.Y.Liu,D.B.Schatz,Theinteractionbetweendopamine transporterfunction,genderdifferences,andpossiblelateralityindepression, PsychiatryRes.211(1)(2013)72–77.

[25]Z.M.Ignácio,G.Z.Réus,H.M.Abelaira,J.Quevedo,Epigeneticandepistatic interactionsbetweenserotonintransporterandbrain-derivedneurotrophic factorgeneticpolymorphism:insightsindepression,Neuroscience275 (2014)455–468.

[26]Z.M.Ignácio,G.Z.Réus,H.M.Abelaira,S.E.Titus,A.S.Carlessi,J.R.daLuz,B.I. Matias,L.Bruchchen,M.Carvalho-Silva,L.M.Gomes,J.Rebelo,E.L.Streck,J. Quevedo,Acuteandchronictreatmentswithquetiapineincrease mitochondrialrespiratorychaincomplexactivityintheratbrain,Curr. Neurovasc.Res.12(3)(2015)283–292.

[27]N.H.Jensen,R.M.Rodriguiz,M.G.Caron,W.C.Wetsel,R.B.Rothman,B.L.Roth, N-desalkylquetiapine,apotentnorepinephrinereuptakeinhibitorandpartial 5-HT1Aagonist,asaputativemediatorofquetiapine’santidepressant activity,Neuropsychopharmacology33(10)(2008)2303–2312. [28]P.Jones,D.Takai,TheroleofDNAmethylationinmammalianepigenetics,

Science293(2001)1068–1070.

[29]T.Kouzarides,Chromatinmodificationsandtheirfunction,Cell128(2007) 693–705.

[30]M.H.Kuo,C.D.Allis,Rolesofhistoneacetyltransferasesanddeacetylasesin generegulation,Bioessays20(8)(1998)615–626.

(8)

monotherapyinacutephaseformajordepressivedisorder:ameta-analysis ofrandomized,placebo-controlledtrials,BMCPsychiatry12(2012)160. [36]E.M.Marco,W.Adriani,R.Canese,F.Podo,M.P.Viveros,G.Laviola,

Enhancementofendocannabinoidsignallingduringadolescence:modulation ofimpulsivityandlong-termconsequencesonmetabolicbrainparametersin earlymaternallydeprivedrats,Pharmacol.Biochem.Behav.86(2007) 334–345.

[37]R.Marmorstein,R.C.Trievel,Histonemodifyingenzymes:structures, mechanisms,andspecificities,Biochim.Biophys.Acta(BBA)GeneRegul. Mech.1789(1)(2009)58–68.

[38]P.O.McGowan,A.Sasaki,A.C.D’Alessio,S.Dymov,B.Labonté,M.Szyf,G. Turecki,M.J.Meaney,Epigeneticregulationoftheglucocorticoidreceptorin humanbrainassociateswithchildhoodabuse,Nat.Neurosci.12(3)(2009) 342–348.

[39]M.J.Millan,A.Gobert,F.Lejeune,A.Dekeyne,A.Newman-Tancredi,V. Pasteau,J.M.Rivet,D.Cussac,Thenovelmelatoninagonistagomelatine (S20098)isanantagonistat5-hydroxytryptamine2Creceptors,blockadeof whichenhancestheactivityoffrontocorticaldopaminergicandadrenergic pathways,J.Pharmacol.Exp.Ther.306(2003)954–964.

[40]R.I.Nadeem,H.I.Ahmed,E.E.El-Denshary,Effectofimipramine,paroxetine, andlithiumcarbonateonneurobehavioralchangesofstreptozotocininrats: impactonglycogensynthasekinase-3andbloodglucoselevel,Neurochem. Res.40(9)(2015)1810–1818.

[41]V.Nanni,R.Uher,A.Danese,Childhoodmaltreatmentpredictsunfavorable courseofillnessandtreatmentoutcomeindepression:ametaanalysis,Am.J. Psychiatry169(2)(2012)141–151.

[42]C.F.Ortmann,G.Z.Réus,Z.M.Ignácio,H.M.Abelaira,S.E.Titus,P.deCarvalho, C.O.Arent,M.A.DosSantos,B.I.Matias,M.M.Martins,A.M.deCampos,F. Petronilho,L.J.Teixeira,M.O.Morais,E.L.Streck,J.Quevedo,F.H.Reginatto, EnrichedflavonoidfractionfromCecropiapachystachyaTréculleavesexerts antidepressant-likebehaviorandprotectsbrainagainstoxidativestressin ratssubjectedtochronicmildstress,Neurotox.Res.29(4)(2016)469–483. [43]G.Paxinos,C.Watson,TheRatBrain:StereotaxicCoordinates,2nded.,

AcademicSanDiego,1986.

[44]R.Philibert,A.Madan,A.Andersen,R.Cadoret,H.Packer,H.Sandhu,Serotonin transportermRNAlevelsareassociatedwiththemethylationofanupstream CpGisland,Am.J.Med.Genet.BNeuropsychiatr.Genet.144B(2007)101–105. [45]R.D.Porsolt,A.Bertin,M.Jalfre,Behaviouraldespairinmice:aprimary

screeningtestforantidepressants,Arch.Int.Pharmacodyn.Ther.229(1977) 327–336.

[46]E.Prieto,J.A.Micó,J.J.Meana,S.Majadas,Neurobiologicalbasesof

quetiapineantidepresanteffectinthebipolardisorder,ActasEsp.Psiquiatr.38 (1)(2010)22–32.

[47]G.Rentesi,K.Antoniou,M.Marselos,M.Syrrou,Z.Papadopoulou-Daifoti,M. Konstandi,Earlymaternaldeprivation-inducedmodificationsinthe neurobiological,neurochemicalandbehavioralprofileofadultrats,Behav. BrainRes.244(2013)29–37.

[48]G.Z.Réus,H.M.Abelaira,M.A.dosSantos,A.S.Carlessi,D.B.Tomaz,M.V. Neotti,J.L.Liranc¸o,C.Gubert,M.Barth,F.Kapczinski,J.Quevedo,Ketamine andimipramineinthenucleusaccumbensregulatehistonedeacetylation inducedbymaternaldeprivationandarecriticalforassociatedbehaviors, Behav.BrainRes.256(2013)451–456.

[49]G.Z.Réus,A.S.Carlessi,S.E.Titus,H.M.Abelaira,Z.M.Ignácio,J.R.daLuz,B.I. Matias,L.Bruchchen,D.Florentino,A.Vieira,F.Petronilho,J.Quevedo,A singledoseofS-ketamineinduceslong-termantidepressanteffectsand decreasesoxidativestressinadulthoodratsfollowingmaternaldeprivation, Dev.Neurobiol.75(11)(2015)1268–1281.

[50]E.Richelson,T.Souder,Bindingofantipsychoticdrugstohumanbrain receptorsfocusonnewergenerationcompounds,LifeSci.68(2000)29–39.

regulationandlatermentaldisorders,Neurosci.Biobehav.Rev.38(2014) 17–37.

[55]H.Sugawara,M.Bundo,T.Asai,F.Sunaga,J.Ueda,J.Ishigooka,K.Kasai,T. Kato,K.Iwamoto,EffectsofquetiapineonDNAmethylationinneuroblastoma cellsProg,Neuropsychopharmacol.Biol.Psychiatry56(2015)117–122. [56]T.Suppes,E.Vieta,S.Liu,M.Brecher,B.Paulsson,Trial127Investigators.,.

MaintenancetreatmentforpatientswithbipolarIdisorder:resultsfroma northamericanstudyofquetiapineincombinationwithlithiumor divalproex(trial127),Am.J.Psychiatry166(4)(2009)476–488.

[57]D.Suri,V.Veenit,A.Sarkar,D.Thiagarajan,A.Kumar,E.J.Nestler,S.Galande, V.A.Vaidya,Earlystressevokesage-dependentbiphasicchangesin hippocampalneurogenesis,BDNFexpression,andcognition,Biol.Psychiatry 73(7)(2013)658–666.

[58]M.Szyf,Theearly-lifesocialenvironmentandDNAmethylation,Clin.Genet. 81(2012)341–349.

[59]M.Tachibana,Y.Matsumura,M.Fukuda,H.Kimura,Y.Shinkai,G9a/GLP complexesindependentlymediateH3K9andDNAmethylationtosilence transcription,EMBOJ.27(20)(2008)2681–2690.

[60]Y.Tanibuchi,Y.Fujita,M.Kohno,T.Ishima,Y.Takatsu,M.Iyo,K.Hashimoto, Effectsofquetiapineonphencyclidine-inducedcognitivedeficitsinmice:a possibleroleofalpha1-adrenoceptors,Eur.Neuropsychopharmacol.19(12) (2009)861–867.

[61]D.Todder,S.Caliskan,B.T.Baune,Nightlocomotoractivityandqualityof sleepinquetiapine-treatedpatientswithdepression,J.Clin.

Psychopharmacol.26(6)(2006)638–642.

[62]N.M.Tsankova,O.Berton,W.Renthal,A.Kumar,R.L.Neve,E.J.Nestler, Sustainedhippocampalchromatinregulationinamousemodelofdepression andantidepressantaction,Nat.Neurosci.9(4)(2006)519–525.

[63]C.Tsigos,G.P.Chrousos,Hypothalamic-pituitary-adrenalaxis,

neuroendocrinefactorsandstress,J.Psychosom.Res.53(4)(2002)865–871. [64]J.Verduijn,Y.Milaneschi,R.A.Schoevers,A.M.vanHemert,A.T.Beekman,

B.W.Penninx,Pathophysiologyofmajordepressivedisorder:mechanisms involvedinetiologyarenotassociatedwithclinicalprogression,Transl. Psychiatry5(2015)e649.

[65]A.M.Vranceanu,S.E.Hobfoll,R.J.Johnson,Childmulti-typemaltreatmentand associateddepressionandPTSDsymptoms:theroleofsocialsupportand stress,Child.AbuseNegl.31(1)(2007)71–84.

[66]Y.Wang,T.Chang,Y.C.Chen,R.G.Zhang,H.N.Wang,W.J.Wu,Z.W.Peng,Q.R. Tan,Quetiapineadd-ontherapyimprovesthedepressivebehaviorsand hippocampalneurogenesisinfluoxetinetreatmentresistantdepressiverats, Behav.BrainRes.253(2013)206–211.

[67]I.C.Weaver,N.Cervoni,F.A.Champagne,A.C.D’Alessio,S.Sharma,J.R.Seckl,S. Dymov,M.Szyf,M.J.Meaney,Epigeneticprogrammingbymaternalbehavior, Nat.Neurosci.7(8)(2004)847–854.

[68]L.M.Williams,C.Debattista,A.M.Duchemin,A.F.Schatzberg,C.B.Nemeroff, Childhoodtraumapredictsantidepressantresponseinadultswithmajor depression:datafromtherandomizedinternationalstudytopredict optimizedtreatmentfordepression,Transl.Psychiatry.6(2016)e799. [69]H.Xu,Z.Chen,J.He,S.Haimanot,X.Li,L.Dyck,X.M.Li,Synergeticeffectsof

quetiapineandvenlafaxineinpreventingthechronicrestraintstress-induced decreaseincellproliferationandBDNFexpressioninrathippocampus, Hippocampus16(6)(2006)551–559.

[70]Y.Zhang,Y.Wang,L.Wang,M.Bai,X.Zhang,X.Zhu,DopaminereceptorD2 andassociatedmicroRNAsareinvolvedinstresssusceptibilityandresistance toescitalopramtreatment,Int.J.Neuropsychopharmacol.18(8)(2015)(pii, pyv025).