Blood pressure - renal blood flow relationships in conscious angiotensin II- and phenylephrine-infused rats.

Blood pressure - renal blood flow relationships in conscious angiotensin II- and phenylephrine-infused rats. Am J Physiol Renal Physiol. 2013 Jul 3; Authors: Polichnowski AJ, Griffin KA, Long J, Williamson GA, Bidani AK Abstract Chronic Ang II infusion in rodents is widely used as an experimental model of hypertension, yet very limited data are available describing the resulting BP - RBF relationships in conscious rats. Accordingly, male Sprague-Dawley rats (n=19) were instrumented for chronic measurements of BP (radiotelemetry) and RBF (Transonic). One week later, 2-3 separate 2 hr recordings of BP and RBF were obtained in conscious rats at 24 hr intervals in addition to separate 24 hr BP recordings. Rats were then administered either Ang II (n=11, 125 ng/kg/min) or phenylephrine (PE, n=8, 50 mg/kg/day) as a control, Ang II-independent, pressor agent. Three days later the BP-RBF and 24 hr BP recordings were repeated over several days. Despite similar increases in BP, PE led to significantly greater BP lability at the heart beat and very low frequency bandwidths. Conversely, Ang II, but not PE, caused significant renal vasoconstriction (a 62% increase in renal vascular resistance and a 21% decrease in RBF) and increased variability in BP-RBF relationships. Transfer function analysis of BP (input) and RBF (output) were consistent with a significant potentiation of the renal myogenic mechanism during Ang II administration, likely contributing, i...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research