Reproductive Experience and the Response of Female Sprague–Dawley Rats to Fear and Stress

摘要

Thepresentworkexaminestherelationshipbetweenreproductiveexperience(comprisingbreeding,parturition,andlactation)andthebehavioralandhormonalprocessesoffearandstressinthefemalelaboratoryrat.Previousresearchhasindicatedthatreproductiveexperiencefunctionstodecreasethefemale'sstressresponseinpotentiallyharmfulenvironments,therebyprovidingherwithnumeroussurvivalbenefits,includingdecreasedfearfulness,increasedaggression,andrefinedhuntingskills.Thisstudywasdesignedtodeterminehownulliparous(noreproductiveexperience),primiparous(1reproductiveexperience)andmultiparous(atleast2reproductiveexperiences)ratsrespondtoaPavlovianparadigmoflearnedfear,involvingthepairingofaneutralstimulus(conditionedstimulus)withanaversivestimulus(unconditionedstimulus).Wereportevidencethatreproductiveexperienceislinkedwithfear-responseandanxiety-likebehaviors.Ourfindingsindicatethatreproductiveexperiencehasanadditiveeffect:primiparousmothersshowedadifferentresponsetotheparadigmofconditionedfearnotonlycomparedwiththoseofnulliparousratsaswellasmultiparousmothers.Assessingthecomplexinterconnectionsamongthebehavioralandphysiologicmeasuresrecordedinthisstudy,multidimensionalscalingconfirmedaclearseparationamongthe3groupsofratsintermsofthebehavioralandphysiologicresponsestotheexperimentalparadigm,supportingtheconclusionthatreproductiveexperienceinfluencesthematernalmind.