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Titolo:
The effects of gonadal hormones on the development and expression of the stimulant effects of morphine in male and female rats
Autore:
Stewart, J; Rodaros, D;
Indirizzi:
Concordia Univ, Dept Psychol, Ctr Studies Behav Neurobiol, Montreal, PQ H3G 1M8, Canada Concordia Univ Montreal PQ Canada H3G 1M8 l, Montreal, PQ H3G 1M8, Canada
Titolo Testata:
BEHAVIOURAL BRAIN RESEARCH
fascicolo: 1-2, volume: 102, anno: 1999,
pagine: 89 - 98
SICI:
0166-4328(199907)102:1-2<89:TEOGHO>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
INDUCED LOCOMOTOR-ACTIVITY; STRIATAL DOPAMINE RELEASE; VENTRAL TEGMENTAL AREA; NUCLEUS-ACCUMBENS; SEX-DIFFERENCES; BEHAVIORAL SENSITIZATION; INVIVO MICRODIALYSIS; ROTATIONAL BEHAVIOR; MESOLIMBIC DOPAMINE; AMPHETAMINE;
Keywords:
morphine; locomotor activity; female rats; estradiol; male rats; testosterone;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
38
Recensione:
Indirizzi per estratti:
Indirizzo: Stewart, J Concordia Univ, Dept Psychol, Ctr Studies Behav Neurobiol, 1455Maisonneuve Blvd W, Montreal, PQ H3G 1M8, Canada Concordia Univ 1455 Maisonneuve Blvd W Montreal PQ Canada H3G 1M8
Citazione:
J. Stewart e D. Rodaros, "The effects of gonadal hormones on the development and expression of the stimulant effects of morphine in male and female rats", BEH BRA RES, 102(1-2), 1999, pp. 89-98

Abstract

Previous studies have shown that the behavioral activating effects of the stimulant drug amphetamine are augmented in female rats by estradiol. Here we studied the effects of gonadectomy and gonadal hormone replacement on the stimulant effects of morphine in both females and males. Groups of intact, ovariectomized (Ovex), and Over females given estradiol benzoate (EB) (5 mu g), and groups of intact, castrated, and castrated males given testosterone propionate (30 mu g) were administered five injections of morphine sulphate (10 mg/kg, i.p.) or saline at 3-day intervals. Activity was monitored on each occasion for 2 h. Among females treated with morphine, intact and Ovex-EB animals showed progressive enhancement of activity over sessions, whereas Over animals showed no change. Three days after the last pre-exposuresession, all animals received 5 mg/kg morphine in a test for sensitization. In spite of the lower levels of activity in Over animals, animals from all groups previously exposed to morphine showed a sensitized response to morphine compared with those receiving morphine for the first time. These findings are virtually identical to our previous findings in female rats treated with amphetamine. Among males, only intact animals showed a progressive increase in morphine-induced activity and only in the second hour of testing, but, overall, there was no significant effect of either group or drug during the pre-exposure phase. On the test for sensitization, as seen in females, those males that had been exposed to morphine previously showed a sensitized response to morphine. There were, however, no differences in activitylevels between the groups of males. We conclude that although gonadal hormones, and in particular estradiol, may modify the magnitude of the responseto amphetamine and morphine, they appear not to be involved in those neurochemical and neuronal changes that occur during and following repeated drugexposures, and that underlie the enhanced sensitivity to the stimulant effects of a drug seen when such animals are compared with animals receiving the drug for the first time. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/01/20 alle ore 00:22:31