SYNTAXIN 1A AND 1B DISPLAY DISTINCT DISTRIBUTION PATTERNS IN THE RAT PERIPHERAL NERVOUS-SYSTEM

Syntaxin 1 has been shown to play an outstanding role in synaptic vesi cle exocytosis. Two isoforms of this protein are expressed in neurons; syntaxin 1A and 1B. However. the physiological significance of the oc currence of such closely related isoforms is not still understood. Her e, by means of isoform-specific immunocytochemistry, we show that synt axin 1A and 1B display different patterns of expression in the rat per ipheral nervous system. Nerve terminals of sensory neurons reaching th e spinal cord were clearly enriched in immunoreactive syntaxin 1A. Bot h isoforms alert detected in cell bodies of sensory neurons at the dor sal root ganglia, although specific immunolabelling displayed very dif ferent patterns at the cellular level. Motor endplates and muscle spin dles were only immunostained for syntaxin 1B. Syntaxin 1A was mainly a ssociated with nerve fibres reaching small blood vessels. In addition, nerve plexuses of the enteric nervous system showed immunostaining fo r both syntaxin isoforms. The different distribution pattern of the tw o neuronal syntaxin isoforms in the rat peripheral nervous system coul d be related to isoform-specific biochemical properties involved in th e exocytotic process. (C) 1998 IBRO. Published by Elsevier Science Ltd .