title: Morphological changes of sensory CGRP-immunoreactive and sympathetic nerves in peripheral tissues following chronic denervation.
abstract: The morphological relationship between sensory and sympathetic nerves was studied in tissues of the eye and the oral cavity following chronic sympathetic or sensory denervation. Immunoreactivities for calcitonin gene-related peptide (CGRP) and tyrosine hydroxylase (TH) were used as indexes to assess the changes of the two nerve populations after denervation. Following surgical sympathectomy, a marked increase of CGRP-containing fibres was seen in all tissues studied, while TH-imunoreactive fibres were totally depleated. Conversely, after capsaicin treatment, an increase of TH-immunoreactive nerves was found in the same tissues, concomitant with a sharp decrease of CGRP-immunoreactive nerves. These changes were particularly evident in iridial stroma and around blood vessels in all tissue, where sensory and sympathetic nerves have a closely overlapping distribution pattern. The altered proportion of sensory peptide- and catecholamine-containing nerves following sympathetic and sensory denervation suggest that there is a reciprocal trophic influence between the two nerve subsets, possibly with the intervention of neurotrophic substances such as nerve growth factor. These results indicate a close interaction between sensory peptidergic and sympathetic nervous systems in peripheral organs.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015740:Calcitonin Gene-Related Peptide; D003315:Cornea / Q000294:innervation*; D003714:Denervation; D006168:Guinea Pigs; D006651:Histocytochemistry; D007124:Immunoenzyme Techniques; D007498:Iris / Q000294:innervation*; D009479:Neuropeptides / Q000032:analysis*; D051381:Rats; D013562:Sympathectomy; D014059:Tongue / Q000294:innervation*; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis*
chemical_list: D009479:Neuropeptides; D014446:Tyrosine 3-Monooxygenase; D015740:Calcitonin Gene-Related Peptide