Activation of gamma-aminobutyric acid(B) receptors by baclofen improves visual temporal property of relay cells in the cat lateral geniculate nucleus.

The role of gamma-aminobutyric acid(B) (GABA(B)) receptors in spatial and temporal properties of the neurons was investigated in the cat dorsal lateral geniculate nucleus (dLGN) using flashing spot and drifting grating stimuli. Iontophoresis of baclofen, the selective GABA(B) receptor agonist significantly decreased the spontaneous and visual evoked responses (decreased to 38+/-7%), in which only the sustained component was suppressed sharply. Baclofen affected neither the center-surround antagonism of receptive fields nor the optimal spatial frequency of stimulating gratings. However, baclofen shortened cells' response duration and elevated their temporal frequencies that evoked the maximum and the half maximum response. In contrast, 2-OH-sacrofen, a GABA(B) antagonist showed no significant effect on dLGN cells' spatio-temporal properties. In conclusion, the activation of GABA(B) receptors may improve the temporal response properties of dLGN cells' via the sustained pathway, rather than change the spatial properties.