Response of lymphocyte guanyl cyclase to propranolol, noradrenaline, thymoxamine, and acetylcholine in extrinsic bronchial asthma.

The lymphocyte guanyl cyclase response to alpha-agonists was studied in 10 normal people and 12 patients with bronchial asthma. In the normal subjects alpha-adrenergic stimulation with noradrenaline plus propranolol and cholinergic stimulation with acetylcholine evoked significant increases in cyclic guanosine monophosphate formation. In addition the alpha-receptor blocking drug thymoxamine produced a significant stimulation of this enzyme system, and the effects of thymoxamine and acetylcholine were additive. This suggests that receptors for cholinergic and alpha-adrenergic agents are independent. In contrast, lymphocyte guanyl cyclase activity did not show a significant response to these agents in patients with acute asthma. In asthmatic patients in remission the responses were partially restored. The significance of these results for control of bronchomotor tone and the relation of guanyl cyclase activity to cyclic adenosine monophosphate in normal subjects and patients with asthma is discussed.