RAPID COMMUNICATION: Electrophysiological properties of cultured neonatal rat dorsal horn neurons containing GABA and met-Enkephalin like immunoreactivity. Y. H. JO, M.E. STOECKEL AND R. SCHLICHTER. Laboratoire Neurophysiologie Cellulaire et Int‚gr‚e, UMR 7519 CNRS, Universit‚ Louis Pasteur, 21 rue Ren‚ Descartes, 67084 Strasbourg cedex, France..
APStracts 4:358N, 1997.
ABSTRACT
We have developed a culture of neurons dissociated from the most superficial laminae of the neonatal rat spinal cord dorsal horn (DH). Using the perforated-patch clamp technique, we distinguished four types of neurons based on their firing properties in response to intracellular injection of 900 ms lasting current pulses. Type 1 neurons were characterized by a tonic firing. Type 2 neurons displayed marked spike accommodation and fired brief (<500 ms) bursts of action potentials whereas type 3 neurons fired a single spike. Type 4 neurons exhibited different types of firing patterns but all of them possessed a time-dependent inwardly rectifying current activated by membrane hyperpolarization. Met-enkephalin-like immunoreactivity (met-ENK-LI) and glutamic acid decarboxylase-like immunoreactivity (GAD-LI) were co-localized in 42% of the neurons (n=59) which were previously identified electrophysiologically. Type 1, 2, 3 and 4 neurons represented respectively 4%, 64%, 20% and 12% of the population of neurons co-localizing met-ENK-LI and GAD-LI. We conclude that the electrophysiological properties of DH neurons present in our cultures are similar to those described in acute slice or hemisected spinal cord preparations and that met-ENK-LI and GABA-LI are preferentially co-localized in type 2 neurons. 

Received 20 August 1997; accepted in final form 3 December 1997.
APS Manuscript Number J693-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 12 December 1997