were independently controlled by two servo-controlled pumps, and changes in the diameter of the segment were registered by an automated video technique. In the absence of flow, these segments maintained their diameter when intraluminal pressure was changed over the range 30-90 mm Hg. When intraluminal pressure was low (30 mm Hg), flow at 20 pl/min caused dilation. This is half the rate of flow ...

Difficulties in achieving focal temporary cerebral ischemia in experimental animals have delayed study of the prevention and treatment of cerebral infarction. We have succeeded in producing focal cerebral infarction by temporary occlusion of brain arteries. Infarction confined to the anterior portion of the thalamus was obtained by simultaneous occlusion of the 4 cerebral arteries: internal car...

The effect of subarachnoid hemorrhage on metabolic rates in rabbit cerebral arteries was investigated by measuring adenosine triphosphate (ATP) content and L-lactate release. The mean +/- SEM ATP content was 0.38 +/- 0.02 mumol/g wet wt in control rabbit basilar arteries (n = 6). The ATP content decreased significantly to 0.17 +/- 0.02 mumol/g wet wt 2 days after experimental subarachnoid hemor...

1 Possible involvement of sympathetic purinergic transmission in the neurogenic response of dog cerebral and basilar arteries was examined with the use of alpha, beta-methylene ATP and adrenoceptor, cholinoceptor blocking agents. 2 In the isolated basilar arteries, electrical transmural stimulation produced a transient contraction which was frequently followed by a relaxation. This transient co...

This study tested the hypothesis that protein kinase C (PKC) has dual regulation on norepinephrine (NE)-mediated inositol 1,4, 5-trisphosphate [Ins (1,4,5)P(3)] pathway and vasoconstriction in cerebral arteries from near-term fetal ( approximately 140 gestational days) and adult sheep. Basal PKC activity values (%membrane bound) in fetal and adult cerebral arteries were 38 +/- 4% and 32 +/- 4%,...

Epidemiological studies demonstrate that in addition to the increased prevalence of hypertension in old patients, the deleterious cerebrovascular effects of hypertension (including atherosclerosis, stroke, and vascular cognitive impairment) are also exacerbated in elderly individuals. The cellular mechanisms by which aging and hypertension interact to promote cerebrovascular pathologies are not...

The initiation of contractile force in arterial smooth muscle (SM) is believed to be regulated by the intracellular Ca2+ concentration and SM myosin type II phosphorylation. We tested the hypothesis that SM myosin type II operates as a molecular motor protein in electromechanical, but not in protein kinase C (PKC)-induced, contraction of small resistance-sized cerebral arteries. We utilized a S...

Cerebral Atherosclerosis in Japanese. I. Age Related to A therosclerosis • During a period of approximately two years (1965 through 1966), 717 intracranial cerebral arteries (males and females) were obtained from the medicolegal autopsy cases. Systematic grading of the macroscopic severity of cerebral atherosclerosis was performed and the results were reported. In general, cerebral atherosclero...

Background and Purpose—Cerebral vasospasm after subarachnoid hemorrhage (SAH) is a major contributor to mortality and morbidity after aneurysm rupture. Recently, R-type voltage-dependent Ca channel (VDCC) expression has been associated with increased cerebral artery constriction in a rabbit model of SAH. The goal of the present study was to examine whether the blood component oxyhemoglobin (oxy...