Effect of tetraethylammonium and verapamil on noradrenaline release induced by field electrical stimulation and potassium from cat cerebral and femoral arteries

Tritium release evoked by field electrical stimulation (FES) or high potassium (K+) from cat cerebral and femoral arteries prelabelled with 3H-noradrenaline was investigated. The release induced by FES and K+ was reduced by Ca2+ suppression and tetrodotoxin (TTX) but not by verapamil in both vessels. Tetraethylammonium (TEA) increased tritium release evoked by FES and K+, when TTX plus TEA were added together radioactivity secretion induced by FES was practically abolished. These results indicate that FES or K+ induce exocytotic noradrenaline release mainly by propagated action potentials and by similar mechanisms in cerebral and femoral arteries.