[Regulation of arteriolar tonus and EDRF]

The physiological significance of the release of NO by endothelial cells was discussed according to the effects of inhibitors of NO formation and to the observations of Mellander et al. on the reactivity of resistance vessels in cat skeletal muscle. Whole results indicate that NO continually takes patent arteries and decreases systemic resistances. However, NO has minimal effects on the arteriolar side of the vascular tree.