The nasal vascular and airway responses to intracarotid injection of nicotine in the dog

Abstract

The nasal vascular and airway responses to intracarotid injection of nicotine were studied in dogs. Nasal vascular resistance was measured by a change in the perfusion pressure of the nasal mucosa with blood flow maintained constant. Nasal airway resistance was measured by a rhinomanometric method. Intracarotid injection of nicotine (100 μg) increased nasal vascular resistance but lessened nasal airway resistance. Vagosympathectomy, atropine, or propranolol had no effect on the responses whereas hexamethonium completely abolished them. Guanethidine and phentolamine reversed the vascular resistance response; the former completely abolished the airway resistance response and the latter only greatly alleviated it. Hence, both vascular and airway resistance responses to nicotine are due to direct stimulation of the nasal mucosal sympathetic ganglia which subsequently activate the alpha-adrenoreceptors.