Volume 99, Issue 4 p. 629-630
Free Access

Voltage-dependent modulation of rat sensory neurone calcium channel currents by G protein activation: effect of a dihydropyridine antagonist

R.H. Scott

R.H. Scott

Department of Pharmacology, St George's Hospital Medical School, London SW17 0RE

Dept of Physiology, St George's Hospital Medical School, London SW17 0RE.

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A.C. Dolphin

Corresponding Author

A.C. Dolphin

Department of Pharmacology, St George's Hospital Medical School, London SW17 0RE

Department of Pharmacology, St George's Hospital Medical School, London SW17 0RESearch for more papers by this author
First published: April 1990
Citations: 34

Abstract

The ability of a depolarizing prepulse to increase the rate of activation of IBa has been examined in cultured sensory neurones of the rat. Both in control neurones and in the presence internally of the guanine nucleotide analogue, guanosine 5′-O-3-thiotriphosphate (GTPγS) which markedly slows the rate of activation of IBa and reduces its amplitude, a depolarizing prepulse increased the rate of activation of IBa, but did not increase its amplitude measured at the end of the 100 ms voltage step. The calcium channel antagonist (−)-202–791, which we have previously shown to increase the amplitude of IBa in the presence of GTPγS, did not occlude the response to a depolarizing prepulse, suggesting that the mechanism of action of (−)-202–791 is not to disrupt the interaction of the channels with activated G proteins.