The role of the sympathetic nervous system in the regulation of ultradian rhythms in urine excretions

The effects of alpha and beta adrenoreceptors blockade and surgical kidney denervation on ultradian rhythmicity in urine excretion were investigated in four dogs. Pharmacological treatments and surgical denervation of the kidneys suppressed the ultradian rhythmicity in urine flow but did not completely eliminate the ultradian rhythms in urinary osmolality and in electrolyte concentrations. These findings suggest that the autonomic nervous system plays a major role in the regulation of the ultradian rhythms in water excretion in dogs. The partial persistence of ultradian rhythms in urine osmolality and electrolyte concentrations after autonomic denervation supports the assertion that the ultradian rhythms in solute concentrations are regulated by different mechanisms to those of water excretion, suggesting the possible involvement of a multioscillatory system.