Jpn. J. Pharmacol. 78 (1), 75-77 (1998)

Involvement of N-Type Voltage-Activated Ca2+ Channels in the Release of Endogenous Noradrenaline from the Isolated Vascularly Perfused Rat Stomach

Kunihiko Yokotani, Yasunobu Okuma and Yoshitsugu Osumi

Department of Pharmacology, Kochi Medical School, Nankoku, Kochi 783 -8505, Japan

Abstract: We characterized the voltage-activated Ca2+ channels involved in noradrenaline (NA) release from gastric sympathetic neurons using isolated, vascularly perfused rat stomach. The evoked NA release by electrical stimulation of periarterial nerves was abolished by calcium removal from the perfusion medium and by cadmium. omega-Conotoxin GVIA (N-type Ca2+-channel blocker) effectively and omega-conotoxin MVIIC (N/P/Q-type blocker) slightly inhibited the evoked NA, while omega-agatoxin IVA (P-type blocker) had no effect. These results suggest that omega-conotoxin GVIA and omega-conotoxin MVIIC-sensitive N-type Ca2+ channels are involved in NA release from the rat gastric sympathetic nerve terminals.

Keywords: Noradrenaline release, Rat stomach, N-type Ca2+ channel

Copyrightę The Japanese Pharmacological Society 1998

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