ACTIONS OF PRAZIQUANTEL AND 1-METHYLADENINE IN GUINEA-PIG ILEAL LONGITUDINAL MUSCLE

Praziquantel (10-4 M) and 1-methyladenine (5 x 10-4 M) produced mechanical responses in guinea pig ileal longitudinal smooth muscle that were approximately 20% of those produced by muscarinic receptor stimulation. These responses were insensitive to tetrodotoxin and atropine but were dependent upon the extracellular concentration of Ca2+ and were abolished by D 600 at a concentration (10-6 M) which abolished the Ca2+-dependent muscarinic responses. Thus, praziquantel and 1-methyladenine may act as modulators of Ca2+ channel function in guinea pig ileal muscle.