Studies on the muscarinic and antimuscarinic activity of benzyltrimethylammonium bromide (btm)

Abstract

Superfusion of an isolated segment of guinea pig ileum with BTM effectively blocks the contractions induced by histamine, potassium chloride, acetylcholine, and BTM itself for a period of 60–90min. Spontaneous contractions are also eliminated during this period. Incorporation of atropine in the superfusate removes the blocking activity of BTM, while hexamethonium has no effect on BTM blockade under similar experimental conditions. Perfusion of isolated gut loops of dogs by BTM causes blockade of contractions induced by histamine and acetylcholine. Epinephrine responses were unaffected. However, BTM caused a reduction in the perfusion pressure response to acetylcholine and histamine while the epinephrine response was increased. The pressor response of epinephrine and the depressor response of acetylcholine were significantly reduced in both the systemic and perfused limb blood pressures of the dog following i.m. administration of 1 mg./kg. of BTM.