Cigarette smoke-induced airway goblet cell secretion: dose-dependent differential nerve activation

We studied the effect of acute inhalation of middle-tar cigarette smoke on airway goblet cell secretion in anesthetized guinea pigs. Secretion induced by a low dose of smoke (10 breaths diluted 1:10 in air) was blocked by either hexamethonium or by filtering out the particulate phase of the smoke. The response was partially inhibited by atropine but was not inhibited by propranolol, phentolamine, or capsaicin pretreatment. Cutting the nerve supply to the airways did not inhibit the response to low-dose smoke. In contrast, goblet cell secretion induced by a high dose of cigarette smoke (20 breaths undiluted) was inhibited by capsaicin pretreatment but not by autonomic receptor blockade nor by filtering out the particulate phase. Secretion induced by the vapor phase of the high dose of cigarette smoke was blocked by capsaicin pretreatment but was not inhibited by hexamethonium. We conclude that in guinea pig airways the particulate phase of low doses of smoke activates cholinergic nerves via stimulation of parasympathetic ganglia, whereas the vapor phase of high doses of smoke activates capsaicin-sensitive sensory nerves.