title: Influence of early beta-endorphin treatment on the behavior and reaction to beta-endorphin in the adult male rat.
abstract: A study was made of the influence of early exposure to beta-endorphin (beta-END) on the adult behavior and response to beta-END in male rats. beta-END was given during a neonatal period, at 1-5 days of age (1 microgram/animal/day s.c.). Recordings of the development of home-nest-orientation ability, body weights, and sex-specific approach behavior showed that the early beta-END treatment did not have debilitating or other non-specific effects. The early beta-END treatment did cause significant changes in the establishment of the adult pattern of sex-specific approach behavior. Copulatory behavior was not apparently influenced. Intracerebroventricular injection of beta-END (1 microgram) at an adult age induced changes in exploratory and copulatory behaviors and in the pattern of sex-specific approach behavior. The reaction to this treatment with respect to components of socio-sexual behavior differed significantly between males treated early with beta-END and their corresponding controls. No differences were observed in behaviors in the exploratory test situation. It is concluded that early beta-END treatment in rats influences components of socio-sexual behavior and the response to exogenous beta-END in adulthood.
authors.forename: B J
authors.initials: BJ
authors.lastname: Meyerson
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects; D003307:Copulation; D004723:Endorphins / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D005260:Female; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009425:Nesting Behavior / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012726:Sexual Behavior, Animal / Q000187:drug effects; D012919:Social Behavior; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D001615:beta-Endorphin