Direct inhibitory effect of neurotensin on isolated gastric smooth muscle cells of guinea pig via the cyclic GMP system.
Smooth muscle cells isolated from the gastric muscle layers of the guinea pig were used to determine whether neurotensin can inhibit the contractile response produced by 10(-6) M carbachol by exerting a direct action on muscle cells. In addition, the inhibitory effect of 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, and methylene blue, an inhibitor of guanylate cyclase, on the neurotensin-induced relaxation of gastric smooth muscle cells were examined. Neurotensin inhibited the contractile response produced by carbachol in a dose-dependent manner, with an IC50 value of 5 nM. 2',5'-Dideoxyadenosine did not have any significant effect on the neurotensin-induced relaxation. On the other hand, methylene blue significantly inhibited the relaxation produced by neurotensin. These results strongly suggest that the action of neurotensin is mediated by cyclic GMP.
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Y
Y
Chijiiwa
O
O
Kawakami
T
T
Misawa
T
T
Kabemura
H
H
Nawata
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000502:physiology*; D016048:Dideoxyadenosine / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects*; D009496:Neurotensin / Q000494:pharmacology*; D013270:Stomach / Q000166:cytology*
D009496:Neurotensin; D016048:Dideoxyadenosine; D002217:Carbachol; D006152:Cyclic GMP; D008751:Methylene Blue