Synaptotagmin I is present mainly in autonomic and sensory neurons of the rat peripheral nervous system

Neuroscience. 1994 Dec;63(3):837-50. doi: 10.1016/0306-4522(94)90528-2.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autonomic Nervous System / cytology
  • Autonomic Nervous System / metabolism*
  • Axons / metabolism
  • Calcium-Binding Proteins*
  • Fluorescent Antibody Technique
  • Immunohistochemistry
  • Male
  • Membrane Glycoproteins / metabolism*
  • Microscopy, Confocal
  • Nerve Crush
  • Nerve Tissue Proteins / metabolism*
  • Neurons, Afferent / metabolism*
  • Peripheral Nervous System / cytology
  • Peripheral Nervous System / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Substance P / metabolism
  • Sympathectomy
  • Synapsins / metabolism
  • Synaptophysin / metabolism
  • Synaptotagmin I
  • Synaptotagmins
  • Tyrosine 3-Monooxygenase / metabolism


  • Calcium-Binding Proteins
  • Membrane Glycoproteins
  • Nerve Tissue Proteins
  • Synapsins
  • Synaptophysin
  • Synaptotagmin I
  • Syt1 protein, rat
  • Synaptotagmins
  • Substance P
  • Tyrosine 3-Monooxygenase