Substance P-containing nerves mediate nicotine-induced contractions of rabbit bronchial smooth muscle.
1. A possible role of substance P-containing nerves in the contractile response to nicotine was investigated in isolated rabbit bronchial smooth muscle preparation. 2. Nicotine caused a contraction which was attributed to the release of acetylcholine in the rabbit bronchus. The response was reduced by capsaicin (10(-5) M) and a substance P antagonist, [D-Arg1, D-Pro2, D-Trp7.9, Leu11] substance P (10(-5) M). 3. Substance P (10(-7) M)-induced contraction was reduced by atropine (10(-6) M) and potentiated by physostigmine (10(-6) M). Furthermore, substance P (10-7 M) enhanced the release of tritium or acetylcholine from the [3H]choline labelled bronchi. 4. Results suggest that substance P-like tachykinin accelerates the nicotine-evoked prejunctional endogenous neural release of acetylcholine on the nervous cells in the rabbit bronchial preparation.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects; D002211:Capsaicin / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009474:Neurons / Q000502:physiology*; D009538:Nicotine / Q000494:pharmacology*; D010830:Physostigmine / Q000494:pharmacology; D011817:Rabbits; D013373:Substance P / Q000502:physiology*
D013373:Substance P; D009538:Nicotine; D001285:Atropine; D006632:Histamine; D010830:Physostigmine; D000109:Acetylcholine; D002211:Capsaicin