Renin release from the ischaemic kidney.

1. We have confirmed that spinal section, and also pithing, inhibits the pressor response associated with the release of renin that follows re-establishment of circulation to the ischaemic rat kidney. Brain transections at bulbar and midthalamic levels did not modify the blood pressure elevation.2. Several pharmacological antagonists of the sympathetic nervous system did not modify the blood pressure response. These observations are not consistent with the view that a neural element is necessary for renin release.3. Constant flow perfusion of the ischaemic kidney in the intact and spinal sectioned rat was performed to evaluate haemodynamic factors involved in renin release. The pressor response was present in spinal sectioned animals under these conditions.4. These results suggest that the nervous system is necessary to maintain adequate blood flow for renin ;washout' into the systemic circulation rather than to release renin from juxtaglomerular cells.