Continuous measurement of renal cortical blood flow and renal arterial blood flow during stimulation of the renal nerve

Abstract

Stimulation of the renal sympathetic nerve in young pigs with biphasic pulses of current (3 mA, 800 microseconds per phase, 5, 10 and 50 Hz) produced decreases in arterial and cortical blood flow in the kidney, with the greatest decreases occurring at the highest stimulus frequencies. The decrease in cortical flow lagged that in arterial flow by 1.53-1.99 s; the delay increased with decreasing frequency but was unaffected by captopril, an angiotensin-converting enzyme-blocking agent. This result was consistent with the hypothesis that stimulation of the sympathetic nerve causes constriction first in the afferent arteriole and then in the efferent arteriole. Systemic arterial pressure increased during stimulation of the nerve; the increase was greater in intact nerves than in nerves that had been crushed proximal to the point of the stimulus, indicating that pigs do have renal afferent nerves. Pressure increased after the stimulus ended, but the increase abated or changed to a decrease after administration of captopril. The changes in flow were unaffected by administration of captopril, but were markedly reduced by the blocking agent labetalol (renal arterial flow, 77 +/- 14 per cent; cortical flow, 70 +/- 12 per cent). Thus, the observed changes in flow resulted from direct stimulation of the sympathetic nerves and not from stimulation of the renin-angiotensin system, which affects the pressure response after the stimulus.

Renal Denervation Improves Exaggerated Sympathoexcitation in Rats With Heart Failure

“…20, 69, 70 It is possible that a pathological signal, which remains to be identified, from the kidney may initiate an increase in ARN activity, whereby causing an increase in overall sympathetic tone which in turn exuberates the pathological signal (positive feedback loop). In the present study stimulation of the ARN produced an increase in LSNA and these responses were exaggerated in rats with HF, suggesting that the renal mediated activation of the sympathoexcitation is more potent in rats with HF, possibly contributing to the enhanced sympathoexcitation commonly observed in the HF condition.…”

The Development History and Research Tendency of Medical Informatics: Topic Evolution Analysis

“…In the first stage (1964-1991), researchers focused on medical data analysis, including the analysis of patients’ physiological data, such as pulmonary data [ 18 ], cerebrum data [ 19 ], and renal data [ 20 ], as well as the analysis of medical images, such as electroencephalogram [ 21 ] and electromyography [ 22 ]. Medical data analysis studies in this period served a primary role in in the field of medicine, such as providing therapy for patients or assisting physicians with disease diagnosis.…”

The Development History and Research Tendency of Medical Informatics: Topic Evolution Analysis (Preprint)

“…In the first stage , researchers focused on medical data analysis, including the analysis of patients' physiological data, such as pulmonary data [18], cerebrum data [19], and renal data [20], as well as the analysis of medical images, such as electroencephalogram [21] and electromyography [22]. Medical data analysis studies in this period served a primary role in in the field of medicine, such as providing therapy for patients or assisting physicians with disease diagnosis.…”