Effects of selective histamine H3-receptor ligands on prolactin and growth hormone secretion in the rat
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The effects of intracarotid (i.a.) administration of the histamine (HA) H3-receptor agonist (R)-α-methyl-histamine (αMeHA) and of the H3-antagonist thioperamide, (THIO) on basal or morphine (M)-induced prolactin (PRL) and growth hormone (GH) secretion were studied in male rats. M was administered 3 h after the H3-drugs. Neither THIO (2.5 mg/kg) nor αMeHA (10 mg/kg) changed basal PRL levels and only THIO enhanced the PRL-releasing effect of M (6 mg/kg). Basal GH secretion was not modified by THIO. αMeHA slightly increased GH secretion. THIO significantly decreased M-stimulated GH secretion (1 mg/kg, i.a.) and αMeHA slightly increased it. These results, in agreement with previous evidence obtained after central HA administration, indicate that endogenous brain HA facilitates PRL and inhibits GH secretion.
KeywordsGrowth Hormone Morphine Histamine Prolactin Thio
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- T. Watanabe, Y. Taguchi, S. Shiosaka, J. Tanaka, H. Kubota, Y. Terano, M. Tohyama and H. Wada,Distribution of the histaminergic neuron system in the central nervous system of rats: a fluorescent immunohistochemical analysis with histidine decarboxylase as a marker. Brain Res.295, 13–25 (1984).PubMedGoogle Scholar
- M. Garbarg, M. D. Trung Tuong, C. Gros and J. C. Schwartz,Effects of histamine H 3-receptor ligands on various biochemical indices of histaminergic neuron activity in rat brain. Eur. J. Pharmac.164, 1–11 (1989).Google Scholar