Effects of substance P on spontaneous contraction in the flexure region of the guinea pig colon.
Effects of Substance P on spontaneous contractions of the circular muscle of the flexure region of guinea pig colon were studied by mechanical tension recording. Substance P (3 nM-10 nM) produced tonic contraction associated with phasic activities but the contraction was found stronger at higher concentration. Verapamil (3 microM), a voltage dependent L-type Ca(2+) channel blocker completely blocked the spontaneous activities and also Substance P induced contraction. These results suggest that Substance P produce contraction by Ca(2+) influx and the Ca(2+) influx occurs by activating verapamil sensitive Ca(2+) channel.
Chowdhury
J U
JU
Department of Physiology, Dhaka National Medical College, Dhaka.
Nahar
N S
NS
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003106:Colon / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006168:Guinea Pigs; D007552:Isotonic Solutions; D008297:Male; D023421:Models, Animal; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D018039:Receptors, Tachykinin / Q000187:drug effects*; D013373:Substance P / Q000494:pharmacology*; D013997:Time Factors; D014700:Verapamil / Q000494:pharmacology*
D002121:Calcium Channel Blockers; D007552:Isotonic Solutions; C051865:Krebs-Ringer solution; D018039:Receptors, Tachykinin; D013373:Substance P; D014700:Verapamil