Differences in adrenoreception in the microcirculatory bed of the pia mater in normotensive and spontaneously hypertensive rats.

Adrenoceptors in pial vascular bed of normotensive Wistar-Kyoto rats are distributed unevenly during stimulation of the superior cervical ganglion, their density was maximum in the 5th-generation arteries. In spontaneously hypertensive rats (SHR) the density of adrenoceptor is lower than in normotensive rats and their number is maximum in the 1st-generation arteries.

Neurogenic vasoconstriction of pial arterial vessels of various branching orders in normotensive and spontaneously hypertensive rats.

Intravital television microscopy was employed to study the reaction of pial arteries in normotensive and spontaneously hypertensive rats to stimulation of the superior cervical ganglion. The amplitude of constrictor response was similar in WKY and SHR animals. Under conditions of normal arterial pressure and arterial hypertension, the maximum constrictor effect was attained due to equal involvement of the arteries from all generations in the normotensive rats and predominant constriction of the precortical arterioles in SHR animals.

Effect of alveolar hypoxia on reactivity of pial vessels in normotensive and spontaneously hypertensive rats.

Intravital television microscopy revealed reduced reactivity of pial arterioles in response to alveolar hypoxia in spontaneously hypertensive rats (SHR) compared to normotensive (WKY) rats, which manifested in decreased number of dilatory reactions and in less pronounced vascular dilation.

[Response of pial arterioles to alveolar hypercapnia in normotensive and hypertensive rats]. / Reaktivnost' k al'veoliarnoi giperkapnii pial'nykh arteriol normotenzivnykh i gipertenzivnykh krys.

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.

[Comparative characteristics of myogenic responses in pial arterioles in normotensive and spontaneously hypertensive rats]. / Sravnitel'naia kharakteristika miogennykh realtsii pial'nykh arteriol normotenzivnykh i spontanno gipertenzivnykh krys.

In acute experiments on SHR and WKY rats, the pial arterioles' myogenic responses to a drop in systemic blood pressure (SBP) were studied. The SHR seem to be more capable of keeping the myogenic activity in low SBP. It might depend on structural changes in the vascular wall under these conditions wall in the SHR.