Role of cyclic AMP protein kinase in decreased arterial cyclic AMP responsiveness in hypertension.

A decreased relaxation responsiveness to isoproterenol and forskolin is manifest in aortic smooth muscle isolated from spontaneously hypertensive rats (SHR) when compared with normotensive Wistar Kyoto (WKY) rats. Inasmuch as the effector of cyclic AMP (cAMP) is cAMP-dependent protein kinase, we sought to determine if alterations in this enzyme might be responsible for this decreased responsiveness to cAMP-increasing vasodilators. The concentration of cAMP protein kinase activity in aortic, carotid and caudal arteries (approximately 300 pmol/mg of protein per min) was similar in both WKY and SHR.

Relationship of guanabenz concentrations in brain and plasma to antihypertensive effect in the spontaneously hypertensive rat.

The antihypertensive agent guanabenz (E-2,6-dichlorobenzylidene aminoguanidine acetate. Wy-8678) was administered i.v.