Evidence against substance P as a neurotransmitter at the neuroepithelial junction in rat colonic mucosa.
Substance P (SP) caused a concentration-dependent increase in short-circuit current of rat isolated colonic mucosal preparations (ED50 10 nM). The SP antagonist [D-Arg1,D-Pro2,D-Trp7,9, Leu11]SP (50 microM) did not increase short-circuit current. Tetrodotoxin (3.1 microM) reduced the effect of a maximum concentration of SP (300 nM). This reduction was increased when tetrodotoxin was given with [D-Arg1,D-Pro2,D-Trp7,9,Leu11]SP. Increases in short-circuit current produced by electrical field stimulation were not reduced by [D-Arg1,D-Pro2,D-Trp7,9,Leu11]SP. It is concluded that SP is not a transmitter at the neuroepithelial junction in rat colonic mucosa.
Burleigh
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Department of Pharmacology, Queen Mary and Westfield College, London, UK.
Yull
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D000818:Animals; D003106:Colon / Q000294:innervation / Q000502:physiology; D004558:Electric Stimulation; D004847:Epithelial Cells; D004848:Epithelium / Q000502:physiology; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000294:innervation* / Q000502:physiology; D008297:Male; D009469:Neuromuscular Junction / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
D018377:Neurotransmitter Agents; D013373:Substance P; D013779:Tetrodotoxin; C038073:substance P, Arg(1)-Pro(2)-Trp(7),(9)-LeuNH(2)(11)-