RETURNYonago Acta medica 1992;35:91–104
Distribution of Calcitonin Gene-Related Peptide Immunoreactive Nerves and Their Coexistence with Acetylcholinesterase Positive Nerves In the Guinea Pig Cornea
Maresada Norikawa*†, Tatsuo Gonda†, Keiichi Ichihara†, Masao Nagata* and Akihiko Tamai*
*Department of Ophthalmology and †Second Department of Pathology, Faculty of Medicine, Tottori University, Yonago 683, Japan
Guinea pig corneas were double-stained with acetylcholinesterase (AChE) staining and calcitonin gene-related peptide (CGRP) immunostaining to study the coexistence of AChE positive nerves and CGRP, a neuropeptide, immunoreactive nerves. In this study, CGRP-immunoreactive nerves were colored purple by the peroxidase-antiperoxidase complex method using 4-chloro-l-naphthol as a coloring agent to allow easy comparison with the brown color of AChE in the same tissue section. Immunohistochemically, thick AChE positive nerve trunks interposed with a few of the thinner varicose CGRP-immunoreactive nerves, were observed in nerve trunks of the corneal stroma and the corneal subepithelial nerve fiber network. CGRP-immunoreactive, but AChE negative nerve fibers, were noted in the corneal stroma, subepithelial nerve fiber network and epithelial cell space, especially in the corneal subepithelium. These findings suggest that CGRP-immunoreactive nerves and AChE positive nerves coexist in the same nerve trunks, but that the former may also exist alone. In addition, both may function in a complex manner while acting on each other.
Key words: acetylcholinesterase positive nerves; calcitonin gene-related peptide immunoreactive nerves; distribution; coexistence; cornea