Myogenic receptivity for Met-enkephalin in the rat duodenum: comparison with the guinea-pig duodenum.
Met-enkephalin (ENK) induced a dose-dependent transient relaxation in vitro in the rat duodenum while morphine neither induced a response nor affected the response to ENK. The response was not blocked by tetrodotoxin but was abolished by naloxone. The response of guinea-pig duodenum to ENK was either relaxation or pulsatile contractions depending on the dose and was abolished by tetrodotoxin.
D000818:Animals; D004347:Drug Interactions; D004386:Duodenum / Q000187:drug effects; D004723:Endorphins / Q000494:pharmacology*; D004744:Enkephalin, Methionine; D004745:Enkephalins / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D051381:Rats; D013045:Species Specificity; D013779:Tetrodotoxin / Q000494:pharmacology
D004723:Endorphins; D004745:Enkephalins; D013779:Tetrodotoxin; D004744:Enkephalin, Methionine; D009020:Morphine