title: Evidence for differential storage of calcitonin gene-related peptide, substance P and serotonin in synaptosomal vesicles of rat spinal cord.
abstract: Homogenates of rat ventral and dorsal spinal cords were subjected to differential and gradient centrifugation on linear sucrose gradients following lysis of a synaptosomal fraction. The distribution of calcitonin gene-related peptide (CGRP) and substance P (SP) in dorsal spinal cord as well as the distribution of serotonin (5-HT) and SP in ventral spinal cord was determined, using radioimmunoassay (RIA) for CGRP and SP and high-performance liquid chromatography for 5-HT. In dorsal spinal cord. CGRP and SP had an almost identical distribution, with one peak in an intermediate density fraction which according to electron microscopy contained i.a. large dense-cored vesicles, and a second peak in a heavy fraction enriched in synaptosome-like structures. In ventral spinal cord, 5-HT and SP had different distribution patterns; 5-HT peaked in a light fraction containing many small synaptic vesicles, whereas SP peaked in an intermediate density fraction similar to the one in dorsal spinal cord. Both 5-HT and SP had second peaks in high density fractions containing synaptosome-like structures. The study demonstrates that the peptides CGRP and SP, partly coexisting in dorsal spinal cord, both seem to be stored in large vesicles inside synaptosomes, whereas the amine 5-HT and the peptide SP, coexisting in ventral spinal cord, appear to have a differential storage with 5-HT mainly in small vesicles and SP in large vesicles, both inside synaptosomes.
authors: Department of Physiology, Karolinska Institutet, Stockholm, Sweden.
authors: G
authors: G
authors: Fried
authors: J
authors: J
authors: Franck
authors: E
authors: E
authors: Brodin
authors: W
authors: W
authors: Born
authors: J A
authors: JA
authors: Fischer
authors: W
authors: W
authors: Hiort
authors: T
authors: T
authors: Hökfelt
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism* / Q000648:ultrastructure; D013373:Substance P / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*
chemical_list: D012701:Serotonin; D013373:Substance P; D015740:Calcitonin Gene-Related Peptide