Effects of indoramin in rat vas deferens and aorta: concomitant alpha(1)-adrenoceptor and neuronal uptake blockade

Effects of indoramin in rat vas deferens and aorta: concomitant alpha(1)-adrenoceptor and neuronal uptake blockade

Author Pupo, André S. Google Scholar
Cavenaghi, Daniela LC Google Scholar
Campos, Marcelo Google Scholar
Morais, Paola D. Google Scholar
Jurkiewicz, Neide Hyppolito Autor UNIFESP Google Scholar
Jurkiewicz, Aron Autor UNIFESP Google Scholar
Institution Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Abstract 1 the actions of the alpha(1)-adrenoceptor antagonist indoramin have been examined against the contractions induced by noradrenaline in the rat vas deferens and aorta taking into account a putative neuronal uptake blocking activity of this antagonist which could. result in self-cancelling actions.2 Indoramin behaved as a simple competitive antagonist of the contractions induced by noradrenaline in the vas deferens and aorta yielding pA(2) values of 7.38 +/- 0.05 (slope = 0.98 +/- 0.03) and 6.78 +/- 0.14 (slope = 1.08 +/- 0.06), respectively.3 When the experiments were repeated in the presence of cocaine (6 mu M) the potency (pA(2)) of indoramin in antagonizing the contractions of the vas deferens to noradrenaline was increased to 8.72 +/- 0.07 (slope = 1.10 +/- 0.05) while its potency remained unchanged in the aorta (pA(2) = 6.69 +/- 0.12; slope = 1.04 +/- 0.05).4 in denervated vas deferens, indoramin antagonized the contractions to noradrenaline with a potency similar to that found in the presence of cocaine (8.79 +/- 0.07; slope = 1.09 +/- 0.06).5 It is suggested that indoramin blocks alpha(1)-adrenoceptors and neuronal uptake in rat vas deferens resulting in Schild plots with slopes not different from unity even in the absence of selective inhibition of neuronal uptake. As a major consequence of this double mechanism of action, the pA(2) values for this antagonist are underestimated when calculated in situations where the neuronal uptake is active, yielding spurious pK(B) values.
Keywords indoramin
alpha(1)-adrenoceptors
vas deferens
aorta
Language English
Date 1999-08-01
Published in British Journal of Pharmacology. Basingstoke: Stockton Press, v. 127, n. 8, p. 1832-1836, 1999.
ISSN 0007-1188 (Sherpa/Romeo, impact factor)
Publisher Stockton Press
Extent 1832-1836
Origin http://dx.doi.org/10.1038/sj.bjp.0702735
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000082312500010
URI http://repositorio.unifesp.br/handle/11600/26118

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