Selective blockade of neurotensin-induced coronary vessel constriction in perfused rat hearts by a neurotensin analogue.
[D-Trp11]-NT, an analogue of neurotensin (NT) in which Tyr11 was replaced with D-Trp, was found to antagonize selectively NT-induced coronary vessel constriction in perfused rat hearts, in concentrations varying between 1.3 x 10(-7) and 1.1 x 10(-6) M. Higher concentrations of [D-Trp11]-NT displayed NT-like activity. In rat stomach strips and guinea pig atria, [D-Trp11]-NT exhibits full intrinsic activity, markedly reduced affinity for NT receptors, but no inhibitory effect against NT. These results suggest that the receptors mediating the constrictor action of NT in the coronary vessels of rat hearts are pharmacologically distinct from those subserving the stimulant effects of NT in rat stomach strips and guinea pig atria.
D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects*; D006321:Heart / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D009496:Neurotensin / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D051381:Rats; D014662:Vasoconstrictor Agents
D014662:Vasoconstrictor Agents; D009496:Neurotensin; C024309:neurotensin, Trp(11)-