Enhancement by endothelin-1 of the release of catecholamines from the canine adrenal gland in response to splanchnic nerve stimulation.

1. The effect of endothelin-1 on the release of adrenal catecholamines was examined in anaesthetized dogs. 2. Splanchnic nerve stimulation (SNS) at 1 and 3 Hz was applied before and after the intravenous injection of endothelin-1. 3. Endothelin-1 (0.1 and 0.3 micrograms/kg) significantly enhanced the release of adrenal catecholamines induced by 3 Hz SNS, but did not affect basal release and the release of adrenal catecholamines induced by 1 Hz SNS. 4. Endothelin-1 produced a slight and short-lasting fall in arterial blood pressure and decreases in adrenal and renal blood flow rates. 5. These results indicate that endothelin-1 enhances the release of adrenal catecholamines from the canine adrenal gland in response to relatively high frequency SNS.