Effects of perineural capsaicin treatment on compound action potentials ofsuperior laryngeal nerve afferents in sevoflurane-anesthetized dogs

Effects of perineural capsaicin (CAPS) treatment on compound action potenti als of the superior laryngeal nerve (SLN) afferents were studied in 6 sevof lurane-anesthetized dogs. Perineural CAPS (100 mu g/ml) to the bilateral SL Ns reduced (P<0.01) the peak and integral amplitudes of the C-wave of the c ompound action potential. By contrast, the perineural CAPS had no effect on the A-wave component (P>0.05). Removal of the perineural CAPS recovered th e C-wave to pretreatment level. The perineural CAPS treatment selectively b locks C-wave compound action potentials of the SLN afferents, providing a u seful tool for studies of laryngeal C-fibers in respiratory physiology.