Neurotensin: A potent vasoconstrictor in the rat hindquarter

Abstract The vasoconstrictor properties of neurotensin (NT) and angiotensin II (AT) were evaluated in isolated, perfused hindquarter, kidney and mesentery of rats. In rat hindquarters, NT (5.4 − 5400 × 10 −9 M) and AT (10 − 500 × 10 −9 M) elicited dose-dependent vasoconstrictor effects while in the other preparations, only AT was active. Low concentrations of NT produced larger increases of perfusion pressure than AT in the rat hindquarter. Higher concentrations of NT and AT evoked responses of similar magnitude. The vasoconstrictor effects of NT in rat hindquarters were selectively inhibited by [D-Trp 11 ]-NT, a newly developed NT antagonist. The inhibition appeared to be of the competitive type. In conclusion, the results indicate that NT is a potent vasoconstrictor in the rat perfused hindquarter.