Effect of substance P and met-enkephalin on cat colonic smooth muscle activity.
1. The effects of substance P (2.5 x 10(-8)M) (SP) and met-enkephalin (10(-7)M) (ME), when administered alone or in combination (SP + ME), on the contractile activity of cat colonic muscle strips were compared. 2. SP evoked powerful contractions of the circular muscle strips (2.30 +/- 0.36 g) (background 0.65 +/- 0.10 g). 3. In the majority of cases, ME significantly increased the background activity (1.88 +/- 0.34 g and 0.70 +/- 0.10 g, respectively). 4. The two substances administered together produced the most pronounced contractile activity (3.86 +/- 0.44 g). 5. The longitudinal muscle strips showed higher spontaneous and evoked contractions. 6. Thus ME contributes to the increase in the effect of SP on colonic contractile activity.
Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
E
E
Atanassova
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M
Papasova
D000818:Animals; D002415:Cats; D003106:Colon / Q000187:drug effects* / Q000502:physiology; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology*
D013373:Substance P; D009270:Naloxone; D004744:Enkephalin, Methionine