A study of the trophic influence of the sympathetic innervation on vascular smooth muscle in normal and disease states

Galway, Gerald James (1984) A study of the trophic influence of the sympathetic innervation on vascular smooth muscle in normal and disease states. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (7MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

While there are probably many factors which influence the structure of blood vessels, recent evidence has suggested that one of the main influences is exerted by the innervation. -- It has been suggested that the innervation of vessels plays a large part not only in vasoconstriction, but also in the growth and maintenance of vessel walls. This trophic influence of nerve on muscle is well documented in skeletal muscle, but less so in the case of vascular smooth muscle. The present study was designed to examine this trophic relationship between the catecholaminergic innervation and the structure of the media of jejunal arteries during normal development and in disease states in which the arterial wall structure is known to change, and in an experimental model in which the innervation has been altered. -- The wall thickness, lumen diameter (and subsequently medial smooth muscle cell mass) and number and disposition of fluorescent sympathetic fibers were determined in varied sets of rats sampled at twelve weeks of age. These sets of rats included normal developing Sprague Dawley rats, spontaneously hypertensive rats (SHR), SHRs treated with capsaicin to lower blood pressure to normotensive levels, Wistar-Kyoto rats (WKY) treated with capsaicin, normal WKY rats, Sprague Dawley rats treated with streptozotocin to induce diabetes, Sprague Dawley rats chemically sympathectomised with 6-hydroxydopamine (6-OHDA), and Sprague Dawley rats with renal artery constrictions to induce hypertension. -- The results of the study indicate that in increase in the medial smooth muscle cell mass observed in the SHR strain of rat is the result of a sympathetic hyper-innervation separate from the influence of an elevated arterial pressure. Furthermore this trophic effect did not extend to the normal state nor to experimentally induced disease states.

Actions (login required)

View Item