Muchun Wang, Shoshiro Okada, Yoshinori Murakami and Kunihiko Yokotani*
Department of Pharmacology, Kochi Medical School, Nankoku, Kochi 783-8505,
Japan
*ÊTo whom all correspondence should be addressed.
Abstract: We examined the effect of nicotine on the release of
endogenous noradrenaline (NA) from the isolated, vascularly perfused rat
stomach. The stomach was perfused via the coeliac artery with Krebs-Ringer
solution containing 10ÊmM pargyline at a constant
flow rate of 4Êml per minute. Nicotine was once applied in the perfusion
medium for 2Êmin. Nicotine (10-6-10-4ÊM) evoked NA
release in a concentration-dependent manner. The nicotine (3Ê«Ê10-5ÊM)-evoked
NA release was abolished by hexamethonium and tetrodotoxin. Diltiazem and
isradipine [blockers of L-type voltage-activated calcium channel (VACC)]
and w-conotoxin GVIA (a blocker of N-type VACC)
also abolished this nicotine-evoked NA release. Previously we reported that
N-type, but not L-type, VACCs are located on the gastric postganglionic
sympathetic nerve terminals, since the NA release evoked by electrical stimulation
of periarterial nerves around the left gastric artery (postganglionic sympathetic
nerves) was abolished by w-conotoxin GVIA, but
not by diltiazem (Yokotani et al.,
Keywords: Nicotine, Release of noradrenaline, Rat stomach, L-type voltage-activated
calcium channel,
N-type voltage-activated calcium channel
Copyright© The Japanese Pharmacological Society 2000
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