1. Experiments were carried out to investigate whether the activation of renal chemoceptive receptors by natural stimuli might induce reflex alterations of efferent postganglionic activity to the ipsilateral kidney and preganglionic activity to the ipsilateral adrenal.
2. In anaesthetized rats with intact nervous system back-flow of urine and occlusion of the renal artery were accompanied by increments in efferent sympathetic activity both to the kidney and adrenal without concomitant changes in heart rate and blood pressure.
3. Greater excitatory responses in nerve activity to the same test stimuli were observed in rats with the spinal cord cut at C1.
4. These results indicate that the natural activation of renal chemoceptive receptors might induce reno-renal and reno-adrenal excitatory reflexes which are likely to be integrated at spinal and supraspinal levels.