Involvement of N-type voltage-activated Ca2+ channels in the release of endogenous noradrenaline from the isolated vascularly perfused rat stomach.
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.
Yokotani
K
K
Department of Pharmacology, Kochi Medical School, Nankoku, Japan.
Okuma
Y
Y
Osumi
Y
Y
D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005753:Gastric Mucosa / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D013111:Spider Venoms / Q000494:pharmacology; D013270:Stomach / Q000187:drug effects / Q000294:innervation; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology; D020867:omega-Agatoxin IVA; D020866:omega-Conotoxin GVIA; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010455:Peptides; D013111:Spider Venoms; D020867:omega-Agatoxin IVA; D020960:omega-Conotoxins; D002104:Cadmium; C075851:omega-conotoxin-MVIIC; D020866:omega-Conotoxin GVIA; D009638:Norepinephrine