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α1-Adrenoceptor subtypes in aorta (α1A) and liver (α1B)

1991; Elsevier BV; Volume: 206; Issue: 3 Linguagem: Inglês

10.1016/s0922-4106(05)80019-7

1872-8251

Ma. Eugenia Torres-Márquez, Rafael Villalobos‐Molina, J. Adolfo García‐Sáinz,

Nitric Oxide and Endothelin Effects

The effect of several alpha 1 adrenoceptor antagonists on the alpha 1-adrenoceptor-mediated stimulation of phosphatidylinositol labeling was studied comparatively in rat hepatocytes and rabbit aorta. It was observed that 5-methyl urapidil and WB 4101 were much more potent in rabbit aorta than in hepatocytes. The orders of potency were prazosin much greater than 5-methyl urapidil greater than or equal to WB 4101 in liver cells and WB 4101 greater than or equal to 5 methyl urapidil = prazosin in aorta. Treatment with chlorethylclonidine inhibited 70-80% of the stimulation of labeling induced by epinephrine in rat liver, but only 30-40% of that in aorta. Our data suggest the existence of two pharmacologically distinct receptors in these tissues i.e.m alpha 1A-adrenoceptors in aorta and alpha 1B in liver cells.