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.
Atanassova
E
E
Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
Papasova
M
M
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