Inhibitory effects of propranolol on the calcium current of Helix neurones.

1 Calcium current (ICa) and potassium current (IK) in isolated nerve cell bodies of Helix aspersa were independently separated after suppression of Na+ and K+ currents, and Na+ and Ca2+ currents, respectively. The suction pipette method was used. Under voltage clamp conditions, the effects of propranolol on both the ICa and IK were examined. 2 Propranolol inhibits the ICa at relatively low concentrations (10(-6)-10(-5) M). The inhibitory action was dose-dependent. 3 The IK was moderately suppressed by the drug at high concentrations (10(-5)-5 X 10(-1) M). 4 Results provide evidence for a new aspect of the pharmacological action of propranolol on the excitable cell membrane.