Increased density of alpha-adrenoceptors in vas-deferens of spontaneously hypertensive rats (SHR), indicated by functional and receptor-binding studies

Increased density of alpha-adrenoceptors in vas-deferens of spontaneously hypertensive rats (SHR), indicated by functional and receptor-binding studies

Author Caricati-Neto, Afonso Autor UNIFESP Google Scholar
Sette, M. Google Scholar
Jurkiewicz, A. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract Pharmacological parameters were determined from contractile responses mediated by alpha-adrenoceptors in vas deferens from spontaneously hypertensive rats (SHR) and corresponding normotensive controls, Wistar Kyoto rats (WKY), and compared with data obtained from radioligand binding assays. Contractile responses induced in longitudinal and circular muscle layers by the alpha-adrenoceptor agonist noradrenaline (NA) and by barium chloride were recorded as described previously. in both muscle layers the maximal effects induced by NA, but not by BaCl2, were significantly greater in SHR. As a consequence, the relative responsiveness ratio (rho) for the alpha-adrenoceptor was also larger for SHR than for WKY. NA-induced contractions of both muscle layers were competitively antagonized by indoramine. the pA2 values for indoramine and pD2 values for NA were the same in SHR and WKY, indicating that alpha-adrenoceptor affinity was not changed in SHR. Additionally, binding studies with thc alpha-adrenoceptor ligand [H-3]WB4101 revealed that B(max) values were greater in the vas deferens of SHR, whereas K(d) values were not significantly different from those of WKY controls. in summary, although differences could not be detected for affinity-related parameters, a greater density of alpha-adrenoceptors was shown for SHR in receptor binding studies and this was corroborated by functional studies.
Keywords VAS DEFERENS
SMOOTH MUSCLE
ALPHA-ADRENOCEPTORS
SPONTANEOUSLY HYPERTENSIVE RATS (SHR)
Language English
Date 1992-07-21
Published in European Journal of Pharmacology. Amsterdam: Elsevier B.V., v. 218, n. 1, p. 51-58, 1992.
ISSN 0014-2999 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 51-58
Origin http://dx.doi.org/10.1016/0014-2999(92)90146-U
Access rights Closed access
Type Article
Web of Science ID WOS:A1992JG59000007
URI http://repositorio.unifesp.br/handle/11600/25266

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