Effects of cicletanine on histamine-induced contractions of isolated rabbit mesenteric arteries
(1989) Fundamental and Clinical Pharmacology — Vol. 3, n° 3, p. 223-235 (1989)
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- The antagonism by cicletanine of contractile responses to histamine has been examined in vitro on ring preparations of rabbit mesenteric arteries. Cicletanine (10(-8)-10(-6) M) caused a parallel rightward shift of histamine concentration response curve, with a pA2 value of 7.48 (slope = 0.89 +/- 0.19, not significantly different from unity). Histamine-induced contractions were nifedipine-sensitive and associated with cicletanine-sensitive increased 45Ca uptake. Endothelium removal resulted in enhanced contractile responses to histamine, but did not significantly modify cicletanine-induced antagonism: KB (dissociation constant) values for cicletanine antagonism in the presence or absence of endothelium were: 3.7 (+/- 0.1) X 10(-8) M and 3.6 (+/- 0.3) X 10(-8) M, respectively. Cicletanine (greater than 10(-4) M) also significantly attenuated 10 mM caffeine-induced contractions in rings exposed to Ca-free 100 mM K+ depolarizing medium. The results suggest that cicletanine-induced antagonisms of histamine H1 receptor-mediated contractions of rabbit mesenteric arteries is associated with interference with calcium entry as well as at high concentrations, release from intracellular stores.
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Ebeigbe, A. B., Cabanie, M., & Godfraind, T. (1989). Effects of cicletanine on histamine-induced contractions of isolated rabbit mesenteric arteries. Fundamental and Clinical Pharmacology, 3(3), 223-235. https://doi.org/10.1111/j.1472-8206.1989.tb00453.x (Original work published 1989)