Fig. 6.

Inhibition of voltage-activated Ca²⁺currents by somatostatin. A, Ca²⁺ currents were evoked in a mass culture neuron by depolarizations from −80 to 0 mV. Traces were recorded before (control), during, and after (wash) the application of 0.1 and 1 μm somatostatin. The inset shows rising phases of Ca²⁺ currents in the very same neuron under control conditions (a), in the presence of 1 μm somatostatin (b), and in the presence of somatostatin, but subsequent to a 50 msec predepolarization to +100 mV, followed by a 5 msec repolarization to −80 mV (c). Calibration, 50 pA, 10 msec. B, Current–voltage relationship of the Ca²⁺ currents in the same neuron as inA before (open circles) and during (solid circles) the application of 1 μmsomatostatin. C, The effect of somatostatin on the current–voltage relationship in B is shown as percentage of inhibition.