AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 5 788-R798, Copyright © 1984 by American Physiological Society
Renal and iliac vascular responses to left ventricular receptor stimulation in conscious dogs
A. J. Gorman, K. G. Cornish and I. H. Zucker
The purpose of the present study was to investigate the relative responses
of the renal and iliac vascular beds to the selective chemical stimulation
of left ventricular receptors in the conscious dog. Twenty dogs were
chronically instrumented to obtain measurements of arterial blood pressure,
renal blood flow, and iliac blood flow before and after a bolus
intracoronary injection of veratridine (0.4-1.0 micrograms/kg in 0.5-ml
vol) with the heart paced. The responses to intracoronary veratridine were
a significant reduction in arterial blood pressure averaging 25 mmHg
accompanied by a simultaneous reduction in renal blood flow of 25%. Renal
resistance did not change throughout the course of the response analyzed
(50 s). Iliac blood flow, however, increased, reaching a peak of 35% above
control due to a 51% decrease in iliac resistance. After sinoaortic
denervation, renal resistance still failed to show a decrease, although the
recovery of arterial blood pressure and iliac resistance was prolonged.
After a mild hypotensive hemorrhage (20 ml/kg), a greater decrease in iliac
resistance occurred with intracoronary veratridine injections, but renal
resistance still did not change. The reduction in iliac resistance with
intracoronary veratridine was significantly attenuated after phentolamine
administration (2 mg/kg iv) but not after atropine alone (0.2 mg/kg iv). A
significant cholinergic receptor component of iliac vasodilation was
observed only after prior alpha-adrenergic-receptor blockade. The results
of this study are consistent with the conclusion that in the conscious dog,
left ventricular receptors exert a preferential neural control over
skeletal muscle vascular resistance and do not influence renal vascular
resistance.
