Activation of sympathoadrenomedullary system increases pulmonary nitric oxide production in the rabbit

Nitric oxide (NO) is continuously produced in the lung and can be measured in exhaled gas of different species. To investigate a possible neuro-humora l regulation of pulmonary NO production in vivo we injected veratrine, an a ctivator of Na+ channels known to activate the sympathoadrenal system, in a naesthetized, mechanically ventilated and laparotomized rabbits. Exhaled NO concentration increased by 38 +/- 3% when plasma adrenaline rose from 12.3 +/- 3.1 to 49.5 +/- 10.7 pmol ml(-1) in response to veratrine (500 mug kg( -1) i.v.). Pretreatment with atenolol, a beta (1)-adrenoceptor antagonist ( 1 mg kg(-1)), or bilateral ligation of adrenal blood vessels inhibited the increase in exhaled NO in response to veratrine. Atenolol also decreased ba sal NO, suggesting an endogenous regulation of pulmonary NO by adrenaline. Neither phentolamine(1 mg kg(-1)). atropine(1 mg kg(-1))nor vagotomy inhibi ted the veratrine-induced pulmonary NO production. These results suggest a role of the sympathoadrenal system in the regulation of pulmonary NO produc tion. (C) 2001 Elsevier Science B.V. All rights reserved.