Nerve growth factor, vessel innervation and hypertensive progression in the inbred Dahl SS/Jr and SR/Jr rats

Abstract

1. To test whether the inbred Dahl salt-sensitive hypertensive rat strain shares disturbed vessel innervation with the spontaneously hypertensive rat (SHR) model, highly innervated and sparsely innervated tissues from the SR/Jr and SS/Jr strains at several ages were assayed for tissue norepinephrine (NE) content and nerve growth factor (NGF). 2. Only two significant differences were found: (i) 1 week old SS/Jr rat kidneys had more NGF than SR/Jr kidneys; and (ii) six week old mesenteric arteries from SS/Jr contained significantly more NE than those in the SR/Jr animals. 3. The differences are in the expected direction for vessel hyperinnervation as a consequence of high vessel NGF, but the data do not support the hypothesis of a central role for vessel NGF and innervation in the hypertensive progression of the Dahl strain. The vessels of young Dahl inbred rat strains do not display the same degree of vessel hyperinnervation associated with hypertension as found in the young SHR compared to WKY strains. 4. The Dahl strain may lack the disturbed NGF metabolism of the SHR. This might suggest that the Dahl inbred strains and the SHR represent two distinct genetic mechanisms that predispose to hypertension via essentially independent processes and that all forms will evidence at least mildly altered vessel innervation.