Figure 7. Effect of pressure on [Ca²⁺]_i in endothelium-intact arteries from fetal and adult sheep during inhibition of endothelium-derived substances.

Intracellular Ca²⁺ concentration of endothelium-intact arteries in physiological salt solution (PSS; □) compared to responses in N^G.-nitro-l-arginine-methyl ester (l-NAME, •), indomethacin (Indo, ○), and l-NAME + Indo (▴) from 95 days gestation fetal (A and D, n = 14), 140 days gestation fetal (B and E; n = 12), and non-pregnant adult (C and F; n = 12) sheep. In all experiments, arteries were exposed to drug solutions for 20 min before determining responses to pressure. Values are means ± s.e.m. *P < 0.05 compared to PSS response, †P < 0.05 compared to Indo response, by ANOVA.