Jpn. J. Pharmacol. 81 (3), 286 - 291 (1999)

The Effect of Nipradilol on the Isoproterenol-Induced Depression
of Contractions in the Cat Soleus Muscle

Toshihiko Tanaka1, Nozomu Murata1 and Yoichi Yamauchi2

1Gifu Research Laboratory, JBC Inc., 52 Fukue, Kaizu-cho, Kaizu-gun, Gifu 503 - 0628, Japan
2Tokyo Research Laboratories, Pharmaceutical Division, Kowa Company, Ltd.,
2 - 17 - 43 Noguchi-cho, Higashimurayama, Tokyo 189 - 0022, Japan

Abstract: The effect of nipradilol on the isoproterelol-induced depression of contractions of the soleus muscle of the anesthetized cats was studied. Isoproterenol (0.3 g/kg) injected intravenously decreased the tension and degree of fusion of incomplete tetanic contractions of the soleus muscle of the anesthetized cats. The effect of isoproterenol was blocked by nipradilol (3 g/kg), desnitro-nipradilol (10 g/kg) and propranolol (10 g/kg), but not by nitroglycerin (10 - 100 g/kg). Nipradilol (30 g/kg) and desnitro-nipradilol (300 g/kg) almost completely antagonized the depressor effects of isoproterenol. These results coupled with evidence that nipradilol does not penetrate the blood-brain barrier indicate that nipradilol exerts an anti-tremor action by blocking peripheral 2-adrenoceptors.

Keywords: Nipradilol, -Blocker, Cat soleus muscle, 2-Adrenoceptor, Isoproterenol

Copyright The Japanese Pharmacological Society 1999

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