Hypertension II: Hypertension and Vascular Control

Arteriolar responsiveness in angiotensin II-induced hypertension

Dr. Imig,
This is a very nice study. It is interesting to me that myogenic responsiveness is unaltered in interlobular and afferent arterioles of the rats made hypertensive by AII infusion. In light of previous reports that sub-pressor concentrations of norepinephrine can enhance arteriolar myogenic responses in rat cremaster muscle, do you think that normal, relatively low circulating levels of AII in vivo could also exert some continuous enhancing effect on myogenic activity? Of course, it may be that any such enhancement would only occur if the vessel were exposed to the AII at the time the myogenic stimulus were applied, which would not be the case if the vessel were being perfused in-vitro. What do you think?

Matt Boegehold

Thu Dec 10