Figure 2.

Influences of ovariectomy and oestrus cycle on endothelium-dependent relaxation induced by ACh in rat mesenteric arteries. (a) Typical traces illustrating the relaxant responses to ACh during 10 μM Phe-induced contraction in mesenteric arteries from sham-operated and ovariectomized rats. (b) Concentration-response curves for ACh-induced relaxation in mesenteric arteries from rats that were sham-operated, ovariectomized, and ovariectomized and 17β-oestradiol-treated. (c) Concentration-response curves for ACh-induced relaxation in mesenteric arteries from oestrus and diestrus rats. ACh was added to the bath cumulatively. The points are means of 6–8 experiments; vertical lines show s.e.mean. Responses are expressed as per cent relaxation of Phe-induced contraction.