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Generalization of a positive-feature interoceptive morphine occasion setter across the rat estrous cycle.
- Source :
-
Hormones and behavior [Horm Behav] 2024 Jun; Vol. 162, pp. 105541. Date of Electronic Publication: 2024 Apr 06. - Publication Year :
- 2024
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Abstract
- Introduction: Interoceptive stimuli elicited by drug administration acquire conditioned modulatory properties of the induction of conditioned appetitive behaviours by exteroceptive cues. This effect may be modeled using a drug discrimination task in which the drug stimulus is trained as a positive-feature (FP) occasion setter (OS) that disambiguates the relation between an exteroceptive light conditioned stimulus (CS) and a sucrose unconditioned stimulus (US). We previously reported that females are less sensitive to generalization of a FP morphine OS than males, so we investigated the role of endogenous ovarian hormones in this difference.<br />Methods: Male and female rats received intermixed injections of 3.2 mg/kg morphine or saline before each daily training session. Training consisted of 8 presentations of the CS, each followed by access to sucrose on morphine, but not saline sessions. Following acquisiton, rats were tested for generalization of the morphine stimulus to 0, 1.0, 3.2, and 5.4 mg/kg morphine. Female rats were monitored for estrous cyclicity using vaginal cytology throughout the study.<br />Results: Both sexes acquired stable drug discrimination. A gradient of generalization was measured across morphine doses and this behaviour did not differ by sex, nor did it differ across the estrous cycle in females.<br />Conclusions: Morphine generalization is independent of fluctuations in levels of sex and endogenous gonadal hormones in females under these experimental conditions.<br />Competing Interests: Declaration of competing interest None.<br /> (Copyright © 2024 Elsevier Inc. All rights reserved.)
- Subjects :
- Animals
Female
Male
Rats
Generalization, Psychological drug effects
Generalization, Psychological physiology
Conditioning, Classical drug effects
Conditioning, Classical physiology
Rats, Sprague-Dawley
Interoception physiology
Interoception drug effects
Discrimination Learning drug effects
Discrimination Learning physiology
Estrous Cycle physiology
Estrous Cycle drug effects
Morphine pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1095-6867
- Volume :
- 162
- Database :
- MEDLINE
- Journal :
- Hormones and behavior
- Publication Type :
- Academic Journal
- Accession number :
- 38583235
- Full Text :
- https://doi.org/10.1016/j.yhbeh.2024.105541