SELECTIVE STIMULATION OF JUGULAR GANGLION AFFERENT NEURONS IN GUINEA-PIG AIRWAYS BY HYPERTONIC SALINE

We evaluated the ability of hyperosmolar stimuli to activate afferent nerves in the guinea pig trachea and main bronchi and investigated the neural pathways involved. By using electrophysiological techniques, s tudies in vitro examined the effect of hyperosmolar solutions of sodiu m chloride (hypertonic saline) on guinea pig airway afferent nerve end ings arising from either vagal nodose or jugular ganglia. The data rev eal a differential sensitivity of airway afferent neurons to activatio n with hypertonic saline. Afferent fibers (both A delta and C fibers) with cell bodies located in jugular ganglia were much more sensitive t o stimulation with hypertonic saline, compared with afferent neurons w ith cell bodies located in nodose ganglia. Additional studies in vivo demonstrated that inhalation of aerosols of hypertonic saline induced plasma extravasation in guinea pig trachea that was mediated via tachy kinin NK1 receptors. Identification of a differential sensitivity of g uinea pig airway afferent nerves to hypertonic saline leads to the spe culation that airway responses to hyperosmolar stimuli may result from activation of afferent neurons originating predominantly from the jug ular ganglion.