Myers A C, Riccio M M, Undem B J
Johns Hopkins Asthma & Allergy Center, Baltimore, MD 21224, USA.
J Allergy Clin Immunol. 1996 Nov;98(5 Pt 2):S107-11; discussion S116-7.
We have developed a guinea pig model that allows monitoring of single afferent nerve fiber activity after stimulation of tracheal nerve endings with various stimuli. Action potentials from nodose or jugular neurons are recorded extracellularly. Previous experiments have shown that the excitability of the nerve endings to, for example, mechanical stimuli can be increased by antigen challenge of presensitized guinea pigs. Nedocromil sodium 10(-4) mol/L significantly reduced by more than 50% the generation of action potentials in C fibers in response to stimulation by capsaicin. The precise mechanism is not known, although the membrane depolarization induced by capsaicin was reduced in the presence of nedocromil sodium. This agent did not have a generalized inhibitory effect on afferent excitability because it had no effect on sensitivity to electrical or mechanical stimuli. Nedocromil sodium did not affect the generation of action potentials in A delta and C fibers in the presence of hypertonic saline solution.
