FIG. 8.

Mechanisms of the control of arterial blood pressure by Cx40. Cx40 seems to play a central role in the control of arterial blood pressure by the parallel coordination of the vasomotor tone of resistance vessels and by renin secretion in the juxtaglomerular apparatus (JGA). Deletion of Cx40 affects the endothelial cell–dependent longitudinal synchronization of the vessel wall function, which results in an impaired conduction of vasodilator responses (36, 57), an irregular vasomotion and segmental constrictions (37). At the same time, the absence of Cx40 in the renin-secreting cells at the JGA disrupts the tonic inhibition of renin system, leading to an increase in renin secretion with the consequent increase in angiotensin II levels (107, 196). The dysregulation in the longitudinal communication of microvessels and renin secretion converges to increase the peripheral vascular resistance and produce the hypertension observed in Cx40-knockout animals (36, 37, 107, 196).