A selective tonic activation of gastrointestinal smooth muscle by substance P.
Mechanical and electrical activity of smooth muscle preparations from fundus, corpus, and antrum of guinea-pig stomach and from distal ileum of guinea-pig were recorded, and the effects of Substance P were examined. Substance P activated selectively the tonic activity of corpus, fundus, and ileum of guinea-pig before and after blockade of phasic contractions. The tonic activation of Substance P is accompanied by increasing of number and amplitude of spike discharges and by decreasing of amplitude of slow potentials in corpus. The tonic activation of Substance P is potentiated parallel with reduction of Ca++ up to 0.6 mmol.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009928:Organ Specificity; D013270:Stomach / Q000187:drug effects*; D013373:Substance P / Q000494:pharmacology*
D013373:Substance P; D002118:Calcium