I. Martinezmir et al., EFFECT OF HISTAMINE ON THE LONGITUDINAL AND CIRCULAR MUSCLE OF THE ESTROGEN DOMINATED RAT UTERUS, Agents and actions, 39(1-2), 1993, pp. 1-5
The response of the longitudinal and circular myometrial strips to his
tamine was studied in oestrogen-treated rats. Histamine produced a dos
e-related inhibitory response in KCl-contracted longitudinal and circu
lar uterine strips. Histamine was equipotent in producing the relaxant
response but the maximal effect achieved in the longitudinal muscle w
as higher than the circular one. Ranitidine antagonized the histamine-
induced relaxation with a similar dose ratio in both longitudinal and
circular strips. Clemizole and reserpine treatment did not produce any
modification of the dose-response curve to histamine. In the longitud
inal and circular strips which were not preconstricted by KCl, neither
histamine nor 2-pyridylethylamine, even in strips pretreated with ran
itidine, produced any effect when added to the organ bath. Our results
show that the response of histamine in both longitudinal and circular
uterine layers of the oestrogen-treated rats are mediated exclusively
by histamine H-2-receptors.