NITRIC-OXIDE

Physiological effects of nitric oxide: The generation of nitric oxide by the vascular endothelium maintains a vasodilator tone that is essen tial for the regulation of blood flow and pressure. In the brain, nitr ic oxide acts as a mediator of cell-cell signalling. In the peripheral nervous system nitric oxide is also released from many nerves previou sly classified as non-adrenergic and non-cholinergic. Thus this simple gaseous molecule performs a wide variety of physiological functions. Potential for therapeutic manipulation: Impaired production of nitric oxide can be countered by the administration of nitric oxide donors (i n hypertension, atherosclerosis, gastrointestinal and genitourinary di sorders) or by inhalation of nitric oxide gas (in chronic pulmonary hy pertension or adult respiratory distress syndrome). The biggest challe nge is to develop strategies that target the cytotoxic and damaging ac tions of nitric oxide without interfering with its essential protectiv e functions.