The role of sympathetic reflex control of cerebral blood flow and microcirculation during normoxia and hypoxia

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5671552

Kissen, I

The purpose of this study was to investigate the hypothesis that there is sympathetic reflex regulation of the cerebral blood flow (CBF) and the utilization of microvessels during normoxia and hypoxia. Regional CBF was determined in conscious Long Evans rats with 4-iodo(N-methyl-{sup 14}C)antipyrine. The percentage of the microvessels perfused as determined by comparing perfused microvessels (FITC-dextran), with the total microvasculature (alkaline phosphatase stain). To test this hypothesis, arcs of the proposed reflex were eliminated. The first experiment examined the effect of bilateral superior cervical ganglionectomy on CBF and microcirulation during normoxia and hypoxia. CBF increased during hypoxia from 67 {plus minus} 2 to 115 {plus minus} 3 ml/min/100 g in control, and from 77 {plus minus} 2 to 155 {plus minus} 6 ml/min/100 g in ganglionectomized animals. In control, hypoxic flow to caudal areas was higher than to rostral areas and that difference was prevented by ganglionectomy. Utilization of arterioles during hypoxia increased from 51 {plus minus} 2% to 63 {plus minus} 2% in control, and from 52 {plus minus} 1% to 77 {plus minus} 2% in ganglionectomized group. The percent perfused capillaries during normoxia was 49 {plus minus} 2% in control, and 52 {plus minus} 1% in ganglionectomized group, and during hypoxia it was 73 {plus minus} 2% in both groups. In the second study, cerebral vascular responses to hypoxia were determined after administration of alpha-adrenoceptor antagonists N-methyl chlorpromazine (does not cross the blood-brain barrier), and phenoxybenzamine (crosses the blood-brain barrier). Neither phenoxybenzamine nor N-methyl chlorpromazine affected CBF and microcirculation during normoxia. During hypoxia, they similarly reversed the rostral to caudal gradient of flow, increased utilization of arterioles in rostral brain areas, and did not affect capillaries.

• Research Organization: Rutgers--the State Univ., New Brunswick, NJ (United States)
• OSTI ID: 5671552
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
ANOXIA
ANTIPYRETICS
ANTIPYRINE
AUTONOMIC NERVOUS SYSTEM AGENTS
AZOLES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BLOOD FLOW
BLOOD VESSELS
BLOOD-BRAIN BARRIER
BODY
BRAIN
CAPILLARIES
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARDIOVASCULAR SYSTEM
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
CEREBRAL CORTEX
CEREBRUM
DRUGS
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PERFUSED TISSUES
PYRAZOLES
PYRAZOLINES
RATS
REACTION KINETICS
RODENTS
SYMPATHOLYTICS
TISSUES
TRACER TECHNIQUES
VERTEBRATES