[Influences of acetylcholine, glutamic acid and GABA on the neuronal firings in ventromedial thalamic nucleus].

In this study, it was shown that the neuronal spontaneous firings of ventromedial thalamic nucleus (VM) in rats were increased by acetylcholine (ACH) and glutamic acid (GLU) applied microiontophoretically with an intensity-dependent manner. Both gamma-animobutyric acid (GABA) and baclofen inhibited the spontaneous firings in majority of VM neurons, but the effect of GABA was rapid and short-lasting, while that of baclofen was slow and long-lasting. GABA could reverse the effects of ACH and GLU. The majority of VM neuronal firing rates could be enhanced by bicuculine, while atropine and MK801 had little effect. The results indicate an important convergence of GLUergic, GABAergic and cholinergic activities in the same VM neurons and GABAergic activities tonically inhibit the VM neurons.