NONSPECIFIC SUPERSENSITIVITY OF THE GUINEA-PIG ILEUM PRODUCED BY CHRONIC GANGLION BLOCKADE

¹ Department of Pharmacology, West Virginia University Medical Center, Morgantown, West Virginia

Chronic treatment with chlorisondamine (1.0 mg/kg) three times per day for 5 to 7 days has been demonstrated to produce supersensitivity of the isolated ileum to acetylcholine, histamine, potassium and 5-UT. One day of treatment with chlorisondamine did not alter the sensitivity. Simultaneous pretreatment with carbachol inhibited the development of supersensitivity by chronic ganglion blockade. The supersensitivity could not be demonstrated if the control and pretreated preparations were both in depolarzing K₂SO₄-Ringer's solution. It is concluded that a nonspecific supersensitivity develops in the guinea-pig ileum as a result of chronically reduced activity in the smooth muscle. The results further strengthen the hypothesis that nonspecific supersensitivity is caused by a physiologic change in the smooth muscle beyond the receptors, perhaps in the cell membrane.