The 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.