title: Synaptotagmin I is present mainly in autonomic and sensory neurons of the rat peripheral nervous system.
abstract: The distribution of synaptotagmin I in the peripheral nervous system of the rat was investigated by immunofluorescence and confocal laser scanning microscopy. After crushing of the sciatic nerve, synaptotagmin I-like immunoreactivity accumulated proximally as well as distally to the crushes in thin and medium-sized axons. Double labelling studies revealed that synaptotagmin I co-localized with tyrosine hydroxylase, a marker of sympathetic adrenergic neurons, and with substance P, a marker for sensory neurons. No synaptotagmin I-like immunoreactivity was found in large axons, while accumulations of the synaptic vesicle proteins synaptophysin and synapsin I were found in all types of axons. Furthermore, no synaptotagmin I-like immunoreactivity was detected in motor endplates. In contrast, the protein was found in muscle spindles of young rats and in perivascular terminals, where it co-localized with synaptophysin and synapsin I. Lumbar sympathectomy resulted in a marked reduction of the amount and intensity of synaptotagmin I-like immunoreactivity in sciatic nerve. High magnification revealed that synaptotagmin I-like immunoreactivity was mainly distributed in a fine granular pattern, but large, brightly fluorescent granules which were not labelled by anti-synaptophysin or anti-synapsin I were occasionally observed. We conclude that synaptotagmin I is mainly expressed in adrenergic and sensory neurons and is absent from, or below detection levels, in motoneurons.
authors.affiliation: Department of Anatomy and Cell Biology, University of Göteborg, Sweden.
authors.forename: J Y
authors.initials: JY
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Jahn
authors.forename: A
authors.initials: A
authors.lastname: Dahlström
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000166:cytology / Q000378:metabolism*; D001369:Axons / Q000378:metabolism; D002135:Calcium-Binding Proteins; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D009409:Nerve Crush; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009475:Neurons, Afferent / Q000378:metabolism*; D017933:Peripheral Nervous System / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013373:Substance P / Q000378:metabolism; D013562:Sympathectomy; D016704:Synapsins / Q000378:metabolism; D016708:Synaptophysin / Q000378:metabolism; D050863:Synaptotagmin I; D050857:Synaptotagmins; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D016704:Synapsins; D016708:Synaptophysin; D050863:Synaptotagmin I; C494312:Syt1 protein, rat; D050857:Synaptotagmins; D013373:Substance P; D014446:Tyrosine 3-Monooxygenase