Autoradiographic distribution of 125I calcitonin gene-related peptide binding sites in the rat central nervous system

Abstract

SKOFITSCH, G. AND D. M. JACOBOWITZ. Autoradiographic distribution of v'-:'l calcitonin gene-related peptide binding sites in the rat central nervous system. PEPTIDES 6(5) [975][976][977][978][979][980][981][982][983][984][985][986] 1985.--Using autoradiographic method and "-':'I-Tyr ° rat CGRP as a ligand, receptor binding sites were demonstrated in the rat central nervous system. Saturation studies and Scatchard analysis of CGRP-binding to slide mounted tissue sections containing primarily cerebellum showed a single class of receptors with a dissociation constant of 0.96 nM and a Bm,~x of 76.4 fmol/mg protein, v-'~I-Tyr ° rat CGRP binding sites were demonstrated throughout the rat central nervous system. Dense binding was observed in the telencephaIon (medial prefrontal, insular and outer layers of the temporal cortex, nucleus accumbens, fundus striatum, central and inferior lateral amygdaloid nuclei, most caudal caudate putamen, organum vasculosum laminae terminalis, subfornical organ), the diencephalon (anterior hypothalamic, suprachiasmatic, arcuate, paraventricular, dorsomedial, periventricular, reuniens, rhomboid, lateral thalamic pretectalis and habenula nuclei, zona incerta), in the mesencephalon (superficial layers of the superior colliculus, central nucleus of the geniculate body, inferior colliculus, nucleus of the fifth nerve, locus coeruleus, nucleus of the mesencephalic tract, the dorsal tegmental nucleus, superior olive), in the molecular layer of the cerebellum, in the medulla oblongata (inferior olive, nucleus tractus solitarii, nucleus commissuralis, nuclei of the tenth and twelfth nerves, the prepositus hypoglossal and the gracilis nuclei, dorsomedial part of the spinal trigeminal tract), in the dorsal gray matter of the spinal cord (laminae I-VI) and the confines of the central canal. Moderate receptor densities were found in the septal area, the "head" of the anterior caudate nucleus, medial amygdaloid and bed nucleus of the stria terminalis, the pyramidal layers of the hippocampus and dentate gyri, medial preoptic area, ventromedial nucleus, lateral hypothalamic and ventrolateral thalamic area, central gray, reticular part of the substantia nigra, parvoceUular reticular nucleus, Purkinje cell layer of the cerebellum, nucleus of the spinal trigeminal tract and gracile fasciculus of the spinal cord. The discrete distribution of CGRP-like binding sites in a variety of sensory systems of the brain and spinal cord as well as in thalamic and hypothalamic areas suggests a widespread involvement of CGRP in a variety of brain functions.Calcitonin gene-related peptide CGRP Autoradiography CNS ALTERNATE processing of the rat and human calcitonin genes resulted in a novel peptide, the calcitonin gene-related peptide (CGRP) [1,26,27,33]. This peptide was recently isolated and characterized [18,19]. The 37 amino acid human CGRP was found to differ from rat CGRP in four amino acids. CGRP-Iike immunoreactivity was shown to be widely distributed in the central and peripheral nervous system of man, rat and o...

Calcitonin gene-related peptide-containing pathways in the rat forebrain

“…The distribution of CGRP terminal fields is in relatively good agreement with the distribution of CGRP binding sites in the rat forebrain (Skofitsch and Jacobowitz, 1985a;Inagaki et al, 1986;Sexton et al, 1986;Kruger et al, 1988a;van Rossum et al, 1997). In the forebrain, discrepancy is found only in the nucleus accumbens and in the basolateral amygdaloid nucleus where CGRP binding sites are abundant, but CGRP terminals are scarce.…”

Phasic and Sustained Fear are Pharmacologically Dissociable in Rats

“…Because peptides often act for long periods of time, as we have found from local BNST infusions of either CRF (Liang et al, 1992) or CGRP (Sink et al, 2011), we believe that accelerated development of small molecule ligands for these receptors, and their evaluation in anxiety models such as the one used here, may be a prudent strategy for the development of new anxiolytic compounds with novel mechanisms of action. We have found, for example, that oral administration of the non-peptide CRF-R1 antagonist GSK876008 disrupts sustained, but not phasic startle increases to conditioned fear stimuli (Walker et al, 2009a, b), and also startle increases evoked directly by calcitonin gene-related peptide (CGRP) infusions into the BNST (Sink et al (2011) and unpublished observations), where receptors for both peptides are abundant (Skofitsch and Jacobowitz, 1985;Kruger et al, 1988;Chalmers et al, 1995;Christopoulos et al, 1995). We have also found that intra-BNST CGRP infusions increase anxiety measures in the plus maze, and that intra-BNST infusions of a CGRP antagonist decrease sustained startle increases produced by the predator odor 2,5-dihydro-2,4,5-trimethylthiazoline (Sink et al, 2011).…”

CGRP antagonist infused into the bed nucleus of the stria terminalis impairs the acquisition and expression of context but not discretely cued fear

“…However, the fact that CGRP receptor populations are highly localized to discrete discontiguous areas very much limits the number of possible alternatives. Based on proximity, the most likely alternative (i.e., to the BNST) would be that CGRP 8 -37 was acting on receptors just ventral and lateral to the BNST as this area also contains significant numbers of CGRP receptors (Skofitsch and Jacobowitz 1985;Kruger et al 1988;Christopoulos et al 1995). This population is continuous with that found in the BNST and, as such, it would be difficult to compare these alternatives by evaluating the effect of infusions into the two areas (i.e., it is likely that we are blocking some of these receptors with intra-BNST infusions, and equally likely that infusions into this alternative area would influence BNST CGRP receptors).…”