Secretagogue action of adenosine in the in vivo canine tracheal mucus model.

Adenosine injected via the cranial thyroid artery route into canine tracheas was a very potent and quick acting secretagogue in a unique model of mucus production. It is not known if adenylate cyclase activation was involved, but adenosine caused a statistically significant, dose related enhancement over baseline secretion rates in seventeen mongrel dogs (0.01 mg 18.4 +/- 5.04% increase N.S.; 0.1 mg 62.5 +/- 9.00% P less than 0.001; and 1.0 mg 91.2 +/- 14.1% P less than 0.001). The response was complete in less than two minutes and muscle relaxation usually accompanied the response. Adenosine activation of submucosal glands, mast cells or airway tissue may mean that adenosine is an agonist in pathophysiological abnormalities of the airways.