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Endogenous opioids and the first suckling episode in the rat.
- Source :
-
Developmental psychobiology [Dev Psychobiol] 1998 Sep; Vol. 33 (2), pp. 175-83. - Publication Year :
- 1998
-
Abstract
- Endogenous activity at opioid receptors affects the appetitive behavior of Caesarean-delivered rat pups during presentation of a surrogate nipple that provides milk. Blockade of opioid receptors by peripheral injection of naloxone has no effect on responses evoked by the surrogate nipple. Similarly, blockade of caudal brain opioid receptors by injection of naloxone into the cisterna magna has no effect on the pup's behavior in response to the surrogate nipple. However, blockade of rostral opioid receptors by injection of naloxone into the cerebral ventricles increases the latency to the first oral grasp response, decreases total time on the nipple, and virtually eliminates ingestion of milk from the surrogate nipple (Experiment 1). Blockade of endogenous opioid activity does not affect responses to a nipple that provides distilled water (Experiment 2) or to an empty surrogate nipple (Experiment 3). These data indicate that during the initial suckling episode endogenous opioids in rostral brain regions affect the pup's behavioral responses to the nipple. The results are consistent with the hypothesis that milk engages opioid systems during the first suckling and that endogenous opioids play a role in early suckling.
- Subjects :
- Analysis of Variance
Animals
Animals, Newborn physiology
Animals, Newborn psychology
Cerebral Cortex drug effects
Drug Administration Routes
Feeding Behavior physiology
Female
Injections, Intraventricular
Male
Naloxone pharmacology
Narcotic Antagonists pharmacology
Nipples
Opioid Peptides physiology
Rats
Reaction Time physiology
Receptors, Opioid classification
Receptors, Opioid drug effects
Reward
Sucking Behavior drug effects
Cerebral Cortex physiology
Milk physiology
Rats, Sprague-Dawley physiology
Rats, Sprague-Dawley psychology
Receptors, Opioid physiology
Sucking Behavior physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0012-1630
- Volume :
- 33
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Developmental psychobiology
- Publication Type :
- Academic Journal
- Accession number :
- 9742412