THE ADRENAL-RENAL VASCULAR CONNECTION CONTRIBUTES TO INCREASE IN RENAL VASCULAR-RESISTANCE DURING AN EXPERIMENTAL HYPOTENSION IN THE RAT

The adrenal vascular connection (ARVC) was described for the first tim e in the cat by Cow (1914) and by other authors in the dog, rat, rabbi t and humans. The aim of the present study is to investigate the role of above connection in regulation of renal vascular resistance (RVR), and renal blood flow (RBF) during decrease in blood pressure in the ra t. Animals were divided into three groups. In the first group, mean ar terial pressure (MAP) was unchanged. In the second and the third group MAP was maintained at 50 mmHg. In addition in the third group, an alp ha adrenergic receptor blockade was produced with intravenous infusion of phentolamine. After stabilisation of RBF, in all groups, the tissu e between the adrenal gland and the kidney was cut. RBF and MAP were m easured and recorded. In the first and the third group, the eliminatio n of ARVC neither influenced RBF nor RVR. In the second group the elim ination of ARVC caused increase in RBF and decrease in RVR (p<0.01). R esults of the present study provide the evidence that catecholamines r eaching the kidney, directly from the adrenal gland through ARVC, duri ng the severe hypotension are responsible for reducing of renal blood flow and increase in renal vascular resistance in the rat.