Figure 6.

Influences of ovariectomy and oestrus cycle on endothelium-dependent hyperpolarization induced by ACh in rat mesenteric arteries. Actual recordings of the hyperpolarizing responses to 1 μM ACh in mesenteric arteries from sham-operated (a), ovariectomized (b), ovariectomized and 17β-oestradiol-treated (c), and diestrus (d) rats are shown. (e) Concentration-response curves for ACh-induced hyperpolarization in mesenteric arteries from rats that were sham-operated, ovariectomized, and ovariectomized and 17β-oestradiol-treated. (f) Concentration-response curves for ACh-induced hyperpolarization in mesenteric arteries from oestrus and diestrus rats. The points are means of 11–14 experiments; vertical lines show s.e.mean.