Dual effect of agmatine in the bisected rat vas deferens

Dual effect of agmatine in the bisected rat vas deferens

Author Santos, W. C. Google Scholar
Smaili, Soraya Soubhi Autor UNIFESP Google Scholar
Jurkiewicz, Aron Autor UNIFESP Google Scholar
Piçarro, Ivan da Cruz Autor UNIFESP Google Scholar
Garcez-do-Carmo, L. Google Scholar
Institution Universidade Federal Fluminense (UFF)
Universidade Federal de São Paulo (UNIFESP)
Abstract The functional effects of the amine agmatine, the putative endogenous ligand for alpha(2)-adrenoceptors and imidazoline receptors, in rat vas deferens were investigated by using the epididymal and prostatic portions. Tissues were contracted by electrical stimulation or by exogenous drugs. in electrically stimulated portions, agmatine caused a dual effect on contractions. in the epididymal portion an inhibition on twitch contractions was observed, which was partially antagonised by idazoxan and yohimbine, indicating the involvement of at least a presynaptic alpha(2)-adrenoceptor-mediated mechanism, without the interference of imidazoline receptors. in the prostatic portion, agmatine enhanced the amplitude of twitches. in contractions induced by exogenous drugs, agmatine potentiated, only in the prostatic segment, the effects of noradrenaline (norepinephrine) or ATP; it also enhanced the effect of low concentrations of KCl and blocked the maximum effect of the higher concentrations. Effects induced by agmatine on the exogenous ATP in the prostatic portion were blocked by cromakalim, suggesting a blocking action on the postsynaptic K+ channels, which explains, in part, the potentiation of the twitch amplitude. It was concluded that agmatine interferes with sympathetic neurotransmission, but the physiological relevance of this needs to be better understood because of the high doses employed to induce its effects.
Language English
Date 2003-03-01
Published in Journal of Pharmacy and Pharmacology. London: Royal Pharmaceutical Soc Great Britain, v. 55, n. 3, p. 373-380, 2003.
ISSN 0022-3573 (Sherpa/Romeo, impact factor)
Publisher Royal Pharmaceutical Soc Great Britain
Extent 373-380
Origin http://dx.doi.org/10.1211/002235702720
Access rights Closed access
Type Article
Web of Science ID WOS:000182414200013
URI http://repositorio.unifesp.br/handle/11600/27175

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