VESICAL-RENAL REFLEX: DIURESIS AND NATRIURESIS ACTIVATED BY INTRAVESICAL CAPSAICIN

In the last years the role of capsaicin sensitive innervation, in the activation of the micturition reflex, has been reported in many papers. In our experience, upon the intravesical administration of capsaicin in humans, we noticed an increase of diuresis. No interaction is known about the sensory innervation of the bladder and renal function, so we studied the possibility of the existence of a vesical-renal reflex arc. Twenty-one patients (9 men and 12 women) were randomised to receive intravesical infusion of saline solution containing 10 μM capsaicin. Urine output, glomerular renal filtrate (GRF) and effective plasma renal flow (EPRF), measured by Technetium-99m diethylenetetramine-pentaacetic acid (DTPA) renal scintigraphy, were recorded over twenty minutes before and after the intravesical administration of capsaicin. Urine density, [Na+] and [K+] concentration, and prostaglandin E2 excretion were also determined before and after intravesical administration of capsaicin or vehicle. Instillation of s...