Evidence that a substance P-like peptide mediates the non-cholinergic excitatory response of the carp intestinal bulb (Cyprinus carpio).
The participation of substance P in the noncholinergic contraction induced by transmural stimulation (TMS) of the carp intestinal bulb was examined. In the presence of atropine, substance P caused the contraction of carp intestinal bulb smooth muscle in a concentration dependent manner (1 nmol/l - 1 mumol/l). The EC50 value was 28 +/- 7 nmol/l (n = 6). Substance P-induced desensitization (1 mumol/l for 15 min), decreased the response to substance P and the atropine-resistant contraction induced by TMS (20 Hz) selectively. In contrast, in the absence of atropine, the contraction induced by TMS (20 Hz) was slightly attenuated with the substance P-induced desensitization. The acid extract obtained from the carp intestinal bulb contained a smooth muscle excitatory material whose pharmacological properties were consistent with those of substance P. The present results indicate that a substance P-like peptide is present in the carp intestinal bulb which is involved in the non-cholinergic contraction induced by TMS.
Kitazawa
T
T
Department of Veterinary Pharmacology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Aomori, Japan.
Kudo
K
K
Ishigami
M
M
Furuhashi
H
H
Temma
K
K
Kondo
H
H
D000109:Acetylcholine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002347:Carps / Q000502:physiology*; D003530:Cyprinidae / Q000502:physiology*; D004558:Electric Stimulation; D004744:Enkephalin, Methionine / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007422:Intestines / Q000294:innervation* / Q000502:physiology; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D013373:Substance P / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*; D014020:Tissue Extracts / Q000494:pharmacology
D014020:Tissue Extracts; D013373:Substance P; D004744:Enkephalin, Methionine; D001285:Atropine; D000255:Adenosine Triphosphate; D000109:Acetylcholine