British journal of pharmacology
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1. The effects of N-, P- and Q-type neuronal voltage-operated calcium (Ca2+) channel antagonists on neurotransmission were determined in a range of cardiovascular and urogenital tissues, as well as the diaphragm, isolated from rat or mouse. 2. The pharmacological tools chosen were omega-conotoxin GVIA (CTX GVIA), a selective N-type Ca2+ channel antagonist, the P-type channel blocker (< or = 100 nM) omega-agatoxin IVA (AGA IVA) and omega-conotoxin MVIIC (CTX MVIIC), a non-selective antagonist of N-, P- and Q-type channels. ⋯ These data suggest that N-type Ca2+ channels predominate in the control of sympathetic transmission in the mesenteric artery, vas deferens and right atrium. In the mouse vas deferens (and rat tissue at high stimulus frequency), P- and Q-type channels also mediate Ca2+ influx. P- and Q-type Ca2+ channels control neurosecretion at the motor endplate, with no role for N type channels.