Response of pial arterioles to alveolar hypercapnia in normotensive and hypertensive rats

In the WKY rats, a large number of vessels were dilated in response to alveolar hypercapnia, the rest of the vessels remaining unchanged, whereas both vasodilation and vasoconstriction occurred under the same conditions in the SHR rats. The difference seems to be due to biophysical and/or biochemical specifics of the SHR vascular walls and to partially depend on specific features of haemodynamics in pial vascular micromodules in both strains of rats.