Effects of Ca concentration and Ca channel blockers on noradrenaline release and purinergic neuroeffector transmission in rat tail artery

Abstract

1 The effects of Ca2+ concentration and Ca2+ channel blockers on noradrenaline (NA) and adenosine 5'-triphosphate (ATP) release from postganglionic sympathetic nerves have been investigated in rat tail arteries in vitro. Intracellularly recorded excitatory junction potentials (e.j.ps) were used as a measure of ATP release and continuous amperometry was used to measure NA release. 2 Varying the extracellular Ca21 concentration similarly affected the amplitudes of e.j.ps and NAinduced oxidation currents evoked by trains of ten stimuli at 1 Hz. 3 The N-type Ca2+ blocker, w-conotoxin GVIA (w-CTX GVIA, 0.1 /iM) reduced the amplitudes of both e.j.ps (evoked by trains of ten stimuli at 1 Hz) and NA..