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Sex-selective effects of neonatal isolation on fear conditioning and foot shock sensitivity.
Behav Brain Res. 2005 Feb 28; 157(2):235-44.BB

Abstract

Our previous work demonstrates enduring effects of the early life stress of neonatal isolation (ISO). ISO facilitates appetitive response learning in adult female, but not male rats, and enhances corticosterone levels and stress responsivity in infant and juvenile rats of both sexes. Corticosterone acts at brain areas such as hippocampus that are rich in glucocorticoid receptors, differentiate postnatally, are sexually dimorphic, and involved in learning. Thus, ISO is hypothesized to alter aversive learning in adult rats in a sex-specific manner. This study tests this hypothesis using context and cue fear conditioning. Pups were isolated for 1h a day on postnatal (PN) days 2-9 or were non-handled and were then tested in adulthood (PN70-90). In Experiment 1, context- and cue-elicited freezing and ultrasonic vocalizations (USVs; 22 kHz range) were measured. Experiments 2-4, respectively, examined three unconditioned foot shock responses (flinch, jump, vocalization), unconditioned fear (time in center of an open, novel arena), and appetitive (stroking-induced; 50 kHz range) USVs. ISO had a sex-selective effect on context-induced USVs that may reflect changes in foot shock sensitivity. ISO increases foot shock sensitivity and tends to enhance context-induced fear in female rats, whereas ISO tends to impair context-induced fear in male rats. Overall, male rats show greater conditioned fear, and female rats show greater unconditioned fear as well as enhanced responses to the aversive and appetitive stimuli. The sex-specific effect of ISO on context fear may reflect neuronal reorganization in stress responsive areas and/or sex differences in some unconditioned responses.

Authors+Show Affiliations

Yale University, New Haven, CT 06516, USA. therese.kosten@yale.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15639174

Citation

Kosten, Therese A., et al. "Sex-selective Effects of Neonatal Isolation On Fear Conditioning and Foot Shock Sensitivity." Behavioural Brain Research, vol. 157, no. 2, 2005, pp. 235-44.
Kosten TA, Miserendino MJ, Bombace JC, et al. Sex-selective effects of neonatal isolation on fear conditioning and foot shock sensitivity. Behav Brain Res. 2005;157(2):235-44.
Kosten, T. A., Miserendino, M. J., Bombace, J. C., Lee, H. J., & Kim, J. J. (2005). Sex-selective effects of neonatal isolation on fear conditioning and foot shock sensitivity. Behavioural Brain Research, 157(2), 235-44.
Kosten TA, et al. Sex-selective Effects of Neonatal Isolation On Fear Conditioning and Foot Shock Sensitivity. Behav Brain Res. 2005 Feb 28;157(2):235-44. PubMed PMID: 15639174.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Sex-selective effects of neonatal isolation on fear conditioning and foot shock sensitivity. AU - Kosten,Therese A, AU - Miserendino,Mindy J D, AU - Bombace,Joan C, AU - Lee,Hongjoo J, AU - Kim,Jeansok J, PY - 2004/02/21/received PY - 2004/06/23/revised PY - 2004/07/05/accepted PY - 2005/1/11/pubmed PY - 2005/8/5/medline PY - 2005/1/11/entrez SP - 235 EP - 44 JF - Behavioural brain research JO - Behav Brain Res VL - 157 IS - 2 N2 - Our previous work demonstrates enduring effects of the early life stress of neonatal isolation (ISO). ISO facilitates appetitive response learning in adult female, but not male rats, and enhances corticosterone levels and stress responsivity in infant and juvenile rats of both sexes. Corticosterone acts at brain areas such as hippocampus that are rich in glucocorticoid receptors, differentiate postnatally, are sexually dimorphic, and involved in learning. Thus, ISO is hypothesized to alter aversive learning in adult rats in a sex-specific manner. This study tests this hypothesis using context and cue fear conditioning. Pups were isolated for 1h a day on postnatal (PN) days 2-9 or were non-handled and were then tested in adulthood (PN70-90). In Experiment 1, context- and cue-elicited freezing and ultrasonic vocalizations (USVs; 22 kHz range) were measured. Experiments 2-4, respectively, examined three unconditioned foot shock responses (flinch, jump, vocalization), unconditioned fear (time in center of an open, novel arena), and appetitive (stroking-induced; 50 kHz range) USVs. ISO had a sex-selective effect on context-induced USVs that may reflect changes in foot shock sensitivity. ISO increases foot shock sensitivity and tends to enhance context-induced fear in female rats, whereas ISO tends to impair context-induced fear in male rats. Overall, male rats show greater conditioned fear, and female rats show greater unconditioned fear as well as enhanced responses to the aversive and appetitive stimuli. The sex-specific effect of ISO on context fear may reflect neuronal reorganization in stress responsive areas and/or sex differences in some unconditioned responses. SN - 0166-4328 UR - https://www.unboundmedicine.com/medline/citation/15639174/Sex_selective_effects_of_neonatal_isolation_on_fear_conditioning_and_foot_shock_sensitivity_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0166-4328(04)00257-8 DB - PRIME DP - Unbound Medicine ER -