OBJECTIVE To determine whether oscillations in the cerebrovascular circulation undergo autonomic modulation in the same way as cardiovascular oscillations. DESIGN Cardiovascular and cerebrovascular oscillations were monitored at rest and during sympathetic stimulation (head up tilt). The association with and transmission of the oscillations in the sympathetic (low frequency, LF) and respirato...

The correlation between the increase in velocity of blood flow in both the internal carotid and vertebral arteries during a carotid compression and the cerebrovascular resistance (CVR) was investigated in 11 patients with chronic ischemic cerebrovascular disease and 4 without organic brain lesions. The velocity of blood flow was measured by an ultrasonic Doppler flowmeter. CVR was calculated fr...

Cerebral blood flow (CBF) has been measured using a non-invasive Xenon133 clearance technique in six normal subjects after 2 days pretreatment with oral indomethacin at a dose of 100 mg/day. The results were compared with placebo given in a double blind balanced cross-over design. Indomethacin was found to result in a reduction in resting CBF of about 25% but the reactivity of the cerebrovascul...

Blood and plasma viscosity are the major factors affecting blood flow and normal circulation. Whole blood viscosity is mainly affected by plasma viscosity, red blood cell deformability/aggregation and hematocrit, and other physiological factors. Thirty patients (twenty males + ten females) with age range 50-65 years, normotensive with history of cerebrovascular disorders, were selected accordin...

The systemic administration of norepinephrine has minimal effects on the cerebral circulation, perhaps due to blood-brain barrier mechanisms. To test hypothesis, the cerebrovascular effects of norepinephrine beyond the blood-brain barrier were studied in anesthetized baboons, Intraventricular norepinephrine (40 mug/kg) resulted in significant increases in cerebral blood flow (40%), cerebral oxy...

NEMOTO, E. M., AND H. M. FRANKEL. Cerebrovascular response during progressive hyperthermia in dogs. Am. J. Physiol. 218(4) : 10601064. 1970.-Cerebral blood flow (CBF) was measured using a technique of continuous infusion of 4-radio-iodoantipyrine with external scintillation counting. Rectal temperature (T,), mean arterial pressure (MAP), heart rate (HR), respiration rate (RR), pa029 p&20,, and ...

Fetal cerebrovascular responses to acute hypoxia are fundamentally different from those observed in the adult cerebral circulation. The magnitude of hypoxic vasodilatation in the fetal brain increases with postnatal age although fetal cerebrovascular responses to acute hypoxia can be complicated by age-dependent depressions of blood pressure and ventilation. Acute hypoxia promotes adenosine rel...

Hypertension (HTN) is a major risk factor for all stroke subtypes, infarction as well as hemorrhage.1,2 Evidence from clinical trials shows that control of blood pressure (BP) leads to a substantially lower risk of stroke.3 HTN exerts detrimental actions on the cerebral circulation that play a critical role in its ability to promote cerebrovascular diseases. Angiotensin II (Ang II) is a key med...