Calcitonin gene-related peptide immunoreactivity selectively labels accessory optic nuclei and pathways of the rat visual system.

C E Ribak,Roland A Giolli,Xiao-Xin Yan

doi:10.1007/s002210050212

Abstract

The present study shows the distribution of calcitonin gene-related peptide (CGRP)-immunolabeled neuronal somata and fibers in the accessory optic system of adult rats. CGRP-immunoreactive cell bodies were small to medium-sized and mostly fusiform or oval-shaped. Both immunolabeled somata and fibers were found in the dorsal and lateral terminal nuclei as well as in the interstitial nucleus of the superior fasciculus (posterior fibers); whereas only immunoreactive fibers were found in the ventral division of the medial terminal nucleus, particularly its rostral portion. These results indicate that CGRP-containing neurons are present in all nuclear components of the accessory optic system and suggest that this neuropeptide may play a neuromodulative role in eye movements.

Highlights

Previous studies have analyzed the distribution of calcitonin gene-related peptide (CGRP) in the mammalian central nervous system with immunocytochemical methods
The present findings show the presence of CGRP-immunostained somata and fibers in the DTN, LTN and inSFp, and CGRP-immunostained fibers in the rostral portion of the ventral division of the MTN
Labeled neurons were mapped in the vicinity of the medial geniculate nucleus by Kawai et al (1985), the present description is the first to identify these CGRP-containing profiles as neurons of the accessory optic system (AOS) nuclei

Summary

Introduction

Previous studies have analyzed the distribution of calcitonin gene-related peptide (CGRP) in the mammalian central nervous system with immunocytochemical methods. These studies showed that CGRP neurons and fibers are present in many brain regions (Rosenfeld et al 1983; Kawai et al 1985; Skofitsch and Jacobowitz 1985a; Kruger et al 1988a). They stressed the importance of finding CGRP-immunolabeled axons in specific parts of the somatosensory pathway and in portions of the gustatory and olfactory systems.

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Results

Conclusion