Corelease of GABA/glycine in lamina-X of the spinal cord of neonatal rats.

Spinal-cord slices from neonatal rats were used to record lamina-X neurons using the patch-clamp technique under whole cell recording configuration. Lamina-X surrounds the central canal of the spinal cord and contains sympathetic preganglionic neurons of the central autonomic nucleus. Miniature inhibitory postsynaptic currents were recorded in the presence of tetrodotoxin and kynurenic acid to block action potential-dependent transmitter release and glutamatergic transmissions, respectively. We recorded mixed gamma-amino-n-butyric acid/glycine miniature synaptic currents suggesting that gamma-amino-n-butyric acid and glycine can be coreleased from the same single synaptic vesicles, and that this corelease can be detected by the postsynaptic cell. In addition, acetylcholine can induce the release of gamma-amino-n-butyric acid/glycine by acting presynaptically at nicotinic receptors located on the gamma-amino-n-butyric acid ergic/glycinergic terminals.