Chronic studies on the interaction between nitric oxide and endothelin in cardiovascular and renal function

1. Chronic inhibition of nitric oxide synthase (NOS) results in a persisten t hypertension, while chronic blockade of endothelin ETA receptors has litt le effect on arterial pressure, These findings indicate that nitric oxide ( NO) plays a more significant role than ET-1 in the long-term maintenance of arterial pressure, 2. Although endothelin (ET) appears to contribute to the hypertension in th e early stages of NOS inhibition, blockade of either ETA or both ETA and ET B receptors has only a minor effect on the hypertension beyond the initial 2 weeks of NOS inhibition. 3. Endothelin may play a role in vascular lesion development associated wit h NOS inhibition, at least within the kidney, which may be related to angio tensin II activity. 4. The processes involved in the hypertension associated with chronic NOS i nhibition appear to be dynamic and may include an evolution of ET-1 action, Variability in results from different laboratories may be related to genet ic factors and choice of pharmacological agents.