Afferent discharges from arterial mechanoreceptors in the kidney of the rabbit.

1. Afferent discharges were observed in dissected filaments or single nerve fibres of renal nerves in the rabbit.2. Increasing the arterial perfusion pressure in excised kidney preparations caused an increase in afferent discharge rate. Increasing the venous pressure was without effect. Receptor discharge patterns were compatible with those of the slowly adapting type.3. In vivo, increasing the systemic blood pressure by means of the sinus reflex caused an increase in afferent discharge rate. Afferent discharge patterns showed no synchronicity with heart beat, irrespective of the blood pressure levels.4. It is suggested that mechanoreceptors are present around the arterial walls in the kidney and that they send information about blood pressure levels in the renal artery to the central nervous system.