Opiate antagonism reduces placentophagia and pup cleaning by parturient rats

Anne D. Mayer; Patricia L. Faris; Barry R. Komisaruk; J. S. Rosenblatt

doi:10.1016/0091-3057(85)90314-4

Opiate antagonism reduces placentophagia and pup cleaning by parturient rats

Anne D. Mayer, Patricia L. Faris, Barry R. Komisaruk, J. S. Rosenblatt

Psychiatry & Behavioral Sciences

Research output: Contribution to journal › Article › peer-review

43 Scopus citations

Abstract

Since endogenous opiate mechanisms are activated during parturition, the present study examined in rats the effects of opiate antagonism on maternal care during and shortly after parturition. Endogenous opiate mechanisms were blocked in late pregnant rats by (1) naltrexone pellet implants (Experiment 1); (2) acute naloxone injections of 10 mg/kg (Experiment 2) or 0.1 mg/kg (Experiment 7); or (3) induction of opiate tolerance (Experiment 3). All methods resulted in a significant decrease in placentophagia and/or in cleaning pups of umbilical cords and birth fluids (Experiment 6). Other aspects of maternal care appeared relatively unaffected and 24 hr pup survival rates were lowered only by induction of morphine tolerance (probably via its effects on the young). In nonpregnant females, naloxone produced a small but significant decrease in placentophagia (Experiment 4) whereas morphine-tolerant nonpregnant females consumed placentas as readily as controls (Experiment 5). Thus the inhibition of placentophagia produced by opiate antagonism may be specific to conditions associated with parturition. These findings suggest that endogenous opiates support placenta eating and pup cleaning during and immediately after birth. Mediation may be via opiate effects on ingestive behavior, and/or via a reduction in the stress of parturition which otherwise can interfere with the female's ability to perform these tasks.

Original language	English (US)
Pages (from-to)	1035-1044
Number of pages	10
Journal	Pharmacology, Biochemistry and Behavior
Volume	22
Issue number	6
DOIs	https://doi.org/10.1016/0091-3057(85)90314-4
State	Published - Jun 1985

Bibliographical note

Funding Information:
We wish to thank Dr. A. R. Gintzler for providing naltrexone pellets, and Dr. L. C. Peters for his encouragement and help in the early stages of this project. The secretarial assistance of Ms. S. Goodman is greatly appreciated. We thank Ms. C. Banas for preparation of illustrations. This research was supported in part by grant MH08604 to J.S.R. and NSF grant BNS 78-24504 to B.R.K. Contribution number 398 of the Institute of Animal Behavior.

Keywords

Opiate antagonism
Parturition
Placentophagia
Tolerance

Access

10.1016/0091-3057(85)90314-4

OpenUrl availability

Full text

Cite this

@article{2d365d99836b4702b0bf769b5105da16,

title = "Opiate antagonism reduces placentophagia and pup cleaning by parturient rats",

abstract = "Since endogenous opiate mechanisms are activated during parturition, the present study examined in rats the effects of opiate antagonism on maternal care during and shortly after parturition. Endogenous opiate mechanisms were blocked in late pregnant rats by (1) naltrexone pellet implants (Experiment 1); (2) acute naloxone injections of 10 mg/kg (Experiment 2) or 0.1 mg/kg (Experiment 7); or (3) induction of opiate tolerance (Experiment 3). All methods resulted in a significant decrease in placentophagia and/or in cleaning pups of umbilical cords and birth fluids (Experiment 6). Other aspects of maternal care appeared relatively unaffected and 24 hr pup survival rates were lowered only by induction of morphine tolerance (probably via its effects on the young). In nonpregnant females, naloxone produced a small but significant decrease in placentophagia (Experiment 4) whereas morphine-tolerant nonpregnant females consumed placentas as readily as controls (Experiment 5). Thus the inhibition of placentophagia produced by opiate antagonism may be specific to conditions associated with parturition. These findings suggest that endogenous opiates support placenta eating and pup cleaning during and immediately after birth. Mediation may be via opiate effects on ingestive behavior, and/or via a reduction in the stress of parturition which otherwise can interfere with the female's ability to perform these tasks.",

keywords = "Opiate antagonism, Parturition, Placentophagia, Tolerance",

author = "Mayer, {Anne D.} and Faris, {Patricia L.} and Komisaruk, {Barry R.} and Rosenblatt, {J. S.}",

note = "Funding Information: We wish to thank Dr. A. R. Gintzler for providing naltrexone pellets, and Dr. L. C. Peters for his encouragement and help in the early stages of this project. The secretarial assistance of Ms. S. Goodman is greatly appreciated. We thank Ms. C. Banas for preparation of illustrations. This research was supported in part by grant MH08604 to J.S.R. and NSF grant BNS 78-24504 to B.R.K. Contribution number 398 of the Institute of Animal Behavior.",

year = "1985",

month = jun,

doi = "10.1016/0091-3057(85)90314-4",

language = "English (US)",

volume = "22",

pages = "1035--1044",

journal = "Pharmacology, Biochemistry and Behavior",

issn = "0091-3057",

publisher = "Elsevier Inc.",

number = "6",

}

TY - JOUR

T1 - Opiate antagonism reduces placentophagia and pup cleaning by parturient rats

AU - Mayer, Anne D.

AU - Faris, Patricia L.

AU - Komisaruk, Barry R.

AU - Rosenblatt, J. S.

N1 - Funding Information: We wish to thank Dr. A. R. Gintzler for providing naltrexone pellets, and Dr. L. C. Peters for his encouragement and help in the early stages of this project. The secretarial assistance of Ms. S. Goodman is greatly appreciated. We thank Ms. C. Banas for preparation of illustrations. This research was supported in part by grant MH08604 to J.S.R. and NSF grant BNS 78-24504 to B.R.K. Contribution number 398 of the Institute of Animal Behavior.

PY - 1985/6

Y1 - 1985/6

N2 - Since endogenous opiate mechanisms are activated during parturition, the present study examined in rats the effects of opiate antagonism on maternal care during and shortly after parturition. Endogenous opiate mechanisms were blocked in late pregnant rats by (1) naltrexone pellet implants (Experiment 1); (2) acute naloxone injections of 10 mg/kg (Experiment 2) or 0.1 mg/kg (Experiment 7); or (3) induction of opiate tolerance (Experiment 3). All methods resulted in a significant decrease in placentophagia and/or in cleaning pups of umbilical cords and birth fluids (Experiment 6). Other aspects of maternal care appeared relatively unaffected and 24 hr pup survival rates were lowered only by induction of morphine tolerance (probably via its effects on the young). In nonpregnant females, naloxone produced a small but significant decrease in placentophagia (Experiment 4) whereas morphine-tolerant nonpregnant females consumed placentas as readily as controls (Experiment 5). Thus the inhibition of placentophagia produced by opiate antagonism may be specific to conditions associated with parturition. These findings suggest that endogenous opiates support placenta eating and pup cleaning during and immediately after birth. Mediation may be via opiate effects on ingestive behavior, and/or via a reduction in the stress of parturition which otherwise can interfere with the female's ability to perform these tasks.

AB - Since endogenous opiate mechanisms are activated during parturition, the present study examined in rats the effects of opiate antagonism on maternal care during and shortly after parturition. Endogenous opiate mechanisms were blocked in late pregnant rats by (1) naltrexone pellet implants (Experiment 1); (2) acute naloxone injections of 10 mg/kg (Experiment 2) or 0.1 mg/kg (Experiment 7); or (3) induction of opiate tolerance (Experiment 3). All methods resulted in a significant decrease in placentophagia and/or in cleaning pups of umbilical cords and birth fluids (Experiment 6). Other aspects of maternal care appeared relatively unaffected and 24 hr pup survival rates were lowered only by induction of morphine tolerance (probably via its effects on the young). In nonpregnant females, naloxone produced a small but significant decrease in placentophagia (Experiment 4) whereas morphine-tolerant nonpregnant females consumed placentas as readily as controls (Experiment 5). Thus the inhibition of placentophagia produced by opiate antagonism may be specific to conditions associated with parturition. These findings suggest that endogenous opiates support placenta eating and pup cleaning during and immediately after birth. Mediation may be via opiate effects on ingestive behavior, and/or via a reduction in the stress of parturition which otherwise can interfere with the female's ability to perform these tasks.

KW - Opiate antagonism

KW - Parturition

KW - Placentophagia

KW - Tolerance

UR - http://www.scopus.com/inward/record.url?scp=0021805902&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0021805902&partnerID=8YFLogxK

U2 - 10.1016/0091-3057(85)90314-4

DO - 10.1016/0091-3057(85)90314-4

M3 - Article

C2 - 2991949

AN - SCOPUS:0021805902

SN - 0091-3057

VL - 22

SP - 1035

EP - 1044

JO - Pharmacology, Biochemistry and Behavior

JF - Pharmacology, Biochemistry and Behavior

IS - 6

ER -

Opiate antagonism reduces placentophagia and pup cleaning by parturient rats

Abstract

Bibliographical note

Keywords

Access

OpenUrl availability

Other files and links

Fingerprint

Cite this