Elsevier

Neuroscience

Volume 88, Issue 2, January 1999, Pages 437-446
Neuroscience

Syntaxin 1A and 1B display distinct distribution patterns in the rat peripheral nervous system

https://doi.org/10.1016/S0306-4522(98)00247-4Get rights and content

Abstract

Syntaxin 1 has been shown to play an outstanding role in synaptic vesicle exocytosis. Two isoforms of this protein are expressed in neurons, syntaxin 1A and 1B. However, the physiological significance of the occurrence of such closely related isoforms is not still understood. Here, by means of isoform-specific immunocytochemistry, we show that syntaxin 1A and 1B display different patterns of expression in the rat peripheral nervous system. Nerve terminals of sensory neurons reaching the spinal cord were clearly enriched in immunoreactive syntaxin 1A. Both isoforms were detected in cell bodies of sensory neurons at the dorsal root ganglia, although specific immunolabelling displayed very different patterns at the cellular level. Motor endplates and muscle spindles were only immunostained for syntaxin 1B. Syntaxin 1A was mainly associated with nerve fibres reaching small blood vessels. In addition, nerve plexuses of the enteric nervous system showed immunostaining for both syntaxin isoforms.

The different distribution pattern of the two neuronal syntaxin isoforms in the rat peripheral nervous system could be related to isoform-specific biochemical properties involved in the exocytotic process.

Section snippets

Antibodies

Anti-syntaxin 1 antibodies were raised in rabbits against (His)6-fusion proteins that contained the cytosolic domain of either syntaxin 1A and 1B. These antisera were further purified to obtain two antibody preparations that recognized syntaxin 1A and syntaxin 1B in a separate manner (named BR1A and BR1B, respectively). Purification procedures and characteristics of these antibodies have been previously described.[42]Monoclonal antobodies against HPC1/syntaxin[5]and SV2[12]were kindly given by

Antibody specificity against syntaxin 1A and 1B

Equivalent amounts of both recombinant (His)6-syntaxin proteins were resolved by electrophoresis and proteins were stained with Coomassie Blue. (His)6-syntaxin 1A migrated faster than (His)6-syntaxin 1B, 35 and 42 being their apparent mol. wt, respectively (Fig. 1A). Western blots using HPC1/syntaxin, BR1A and BR1B antibodies are shown in Fig. 1B. HPC1/syntaxin monoclonal antibodies recognized both syntaxin 1 isoforms. BR1A and BR1B antibodies recognized the appropiate isoform against which

Discussion

Since their original description, different members of the syntaxin family (syntaxin 1–6) have been described in various rat tissues.7, 8In particular, the syntaxin 1A and 1B isoforms have been identified in neural and neuroendocrine tissues.1, 6, 25, 26A recent immunocytochemical study revealed striking differences between the distribution of the syntaxin 1 isoforms in the rat CNS.[42]Interestingly, CNS areas that are known to be involved in sensory functions contained intense labelling for

Conclusions

The distinct expression pattern of syntaxin 1A and 1B in the rat peripheral nervous system is shown by the use of specific syntaxin 1 isoform antibodies. The different distribution of the two neuronal syntaxin isoforms could be related to isoform-specific biochemical properties involved in the exocytotic process.

Acknowledgements

The authors wish to thank Drs C. J. Barnstable, K. Buckley and R. Jahn for their generous gift of antibodies and J. Ballabriga for his expert advice. We are grateful to I. Gómez de Aranda for excellent technical assistance. G.M. is in receipt of a fellowship from the Generalitat de Catalunya. This study was supported by a grant from DGICYT and from E.U. project BMH4-CT96-15864.

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