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Pertussis toxin abolishes the effect of neuropeptide Y on rat resistance arteriole contraction
R Andriantsitohaina1, P Andre, J C Stoclet
1Laboratoire de Pharmacologie, Cellulaire et Moléculaire, Unité de Recherche Associée Centre National de la Recherche Scientifique D0600, Université Louis Pasteur de Strasbourg, Faculté de Pharmacie, Illkirch, France.
Abstract:
Pertussis toxin (PTX) was used to investigate the possible involvement of a G protein in the mechanism of action of neuropeptide Y (NPY) on rat mesenteric arterioles. ADP ribosylation of membrane protein was assessed by gel electrophoresis followed by autoradiography. The effect of NPY was studied on contractions elicited either by addition of calcium to depolarized vessels or by the calcium agonist BAY K 8644. Under conditions in which PTX ADP-ribosylated a 40-41 kDa protein, the potentiation of contractions induced by NPY in both protocols was abolished. In contrast, the contraction induced by norepinephrine was unaffected by PTX. It is concluded that a G protein mediates the potentiating effect of NPY on external calcium-dependent contractions in rat mesenteric arterioles.