Effect of bombesin and substance P on the smooth muscle of the chicken crop.
The effect of bombesin and of substance P was investigated in smooth muscle strips of the chicken crop. Bombesin in picomolar concentration (0.1 x 10(-12) - 5 X 10(-12) mol/l) caused a concentration-related contraction of the muscle strips. Substance P in nanomolar concentration (0.1 x 10(-9) - 10 x 10(-9) mol/l) was effective in the same manner. Tetrodotoxin (2 x 10(-7) mol/l) did not influence the contraction responses to either bombesin or substance P. The excitatory effect of bombesin and of substance P did not follow activation of cholinergic receptors since their effect on the crop smooth muscle was not antagonized by atropine (10(-4) mol/l) or by hexamethonium (10(-4) mol/l). Strips stored for 24 hours in the Tyrode's solution at 4 degrees C without a supply of oxygen maintained their full sensitivity to bombesin and to substance P. These results are consistent with a direct action of bombesin and substance P on the crop smooth muscle.
Denac
M
M
Institute of Veterinary Physiology, University of Zürich, Switzerland.
Scharrer
E
E
D000818:Animals; D001839:Bombesin / Q000494:pharmacology*; D002645:Chickens / Q000502:physiology*; D003426:Crop, Avian / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D013373:Substance P / Q000494:pharmacology*
D013373:Substance P; D001839:Bombesin