Abstract

Of all body tissues, the brain is the least tolerant of ischemia so much that interruption of cerebral blood flow by 5 sec can cause syncope, with irreversible tissue damage if the ischemia last a few minutes. In this respect, the body has an imperative duty of ensuring constant and adequate blood supply to the brain. It does so through a series of intrinsic and extrinsic control factors of which adrenergic and nitric oxide-releasing nerves are components. My research examined the interaction between these two nerve-types with emphasis on the mechanisms involved as well as on changes in their functions as the animal adapts to stress such as chronic hypoxia.

An overview of endogenous NO which is synthesized by nNOS, reveals that NO exhibits numerous and wide spread interactions in the nervous system with implications in disease conditions such as Multiple Sclerosis, Schizophrenia, Parkinson’s and Alzheimer’s diseases. On the other hand, beneficial effects of NO include a role in synaptic plasticity and modulation of sympathetic nerve activity in cerebral arteries with potential to modulate cerebral circulation.

This thesis provides evidence supporting the hypothesis that adrenergic and nNOS nerves co-exist within cerebral arteries and strongly suggest an interaction between these two neuron types such that NO released from the nNOS nerves serves to facilitate NE released from the adjacent adrenergic nerves. In addition, evidence in this thesis also show that in the course of adapting to stress such as chronic high altitude hypoxia, the ability of nNOS nerves to modulate adrenergic function is lost. This lost of nNOS nerve function is due at least in part to a decline in the expression of nNOS protein.

The mechanism by which NO modulates adrenergic nerve function has been proposed to involve a cascade of reactions leading to the mobilization of intracellular free calcium within adrenergic nerve terminals. Recall that the release of neurotransmitter such as NE from stored vesicles requires an increase in [Ca2+]i. This thesis provides data in support of the hypothesis that the NO/cGMP-dependent protein kinase -1 pathway controls intracellular calcium mobilization which could underlie the mechanism of NO modulation of adrenergic nerve function in cerebral arteries. However, it remains to be ascertained whether the NO/cGMP-dependent protein kinase-induced mobilization of [Ca2+]l is mediated via cADP ribose.

LLU Discipline

Pharmacology

Department

Pharmacology

School

Graduate School

First Advisor

John N. Buchholz

Second Advisor

Sue P. Duckles

Third Advisor

Mailen Kootsey

Fourth Advisor

William J. Pearce

Fifth Advisor

Lubo Zhang

Degree Name

Doctor of Philosophy (Medical Science)

Degree Level

Ph.D.

Year Degree Awarded

2003

Date (Title Page)

6-2003

Language

English

Library of Congress/MESH Subject Headings

Cerebral Arteries; Nitric Oxide -- pharmacology; Cerebrovascular Circulation; Brain Ischemia; Adrenergic Fibers.

Type

Dissertation

Page Count

xv; 165

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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