KCl-induced changes in arterial diameters and [Ca2+]i were measured simultaneously at intraluminal pressure of 20 mmHg in coronary arteries from 3 month old male and female offspring that had been exposed in utero to saline control or cocaine. A, Typical recordings of KCl-induced increase of [Ca2+]i and decrease of the arterial diameter in the same tissue. B, KCl-induced increases of [Ca2+]i (Δ [Ca2+]i, Rf340/380). C, KCl-induced decreases of the arterial diameter (Δ diameter, µm). Data are means ± SEM. * P < 0.05, female versus male. n=5–7 rats.