Effects of intravesical capsaicin on the substance P- and CGRP-immunoreactive terminals of the rat spinal dorsal horn / 대한해부학회지

Visceral afferent nerve fibers containing substance P or calcitonin gene-related peptide (CGRP) are distributed in the bladder wall, and are known to be stimulated by and then desensitized by capsaicin. Recently, there have been some reports on the effectiveness of intravesical capsaicin administration for the treatment of hypersensitive lower urinary tract disorder or neurogenic bladder. In this study, the effects of intravesical capsaicin on the substance P or CGRP immunoreactivities in the spinal dorsal horn were investigated and the mechanism of capsaicin treatment for bladder disorders was revealed. After intravesical administration of capsaicin, the substance P and CGRP immunoreactive areas were measured at the dorsal horn of L4 and S1 spinal cord. Before capsaicin treatment, the substance P immuno- reactive area was 2.61+/-0.78 x 105 mm2 in L4 and 1.66+/-0.49 x 105 mm2 in S1. The substance P immunoreactivity was markedly reduced 1~2 weeks after capsaicin treatment in both L4 and S1 spinal cord. The CGRP immunoreactive area was 1.74+/-0.52 x 105 mm2 in L4 and 1.14+/-0.69 x 105 mm2 in S1, but was not reduced after capsaicin treatment. Therefore, capsaicin administered intravesically desensitizes nerve fibers containing substance P and consequently suppresses pain and voiding reflex.

Immunohistochemical Localization of Choline Acetyltransferase in External Branch of Superior Laryngeal Nerve in Cat / 대한이비인후과학회지

Existence of the external branch of the superior laryngeal nerve containing afferent fibers is much of concern. In this study, it is the aim to identify the component of fibers by immunohistochemistry using choline acetyltransferase, the specific marker of the cholinergic motor neuron. Both side of external branch of superior laryngeal nerve were excised from 4 adult cats, and also obtained the great auricular nerve and the hypoglossal nerve for sensory control and motor control specimen, respectively. There were no fibers with immune reaction in the great auricular nerve while all of the fibers in the hypoglossal nerve were strongly stained with rabbit anti-choline acetyltransferase antibody. In the external branch of the superior laryngeal nerve, 12.7% of the fibers were not stained with immune reaction product. They are smaller than stained nerve fibers in cross sectioned diameter and peripherally located in the same fascicle. The identification of unstained fiber group in the external branch of the superior laryngeal nerve suggest that it is a mixed nerve and not purely motor, possibly containing the sensory nerve fiber.