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