GABA receptors GABAa

GABA receptor, agonists GABAa—muscimol GAB Ag—baclofen... 

The last few years has seen an explosion in AEDs. Some of those mentioned above may fall by the wayside and others appear. At the time of writing, we could include felbamate, zonisamide oxcarbazepine and topiramate. They all appear to have a phenytoin-like action on sodium channels, although topiramate appears to also potentiate the action of GABA on GABAa receptors like the benzodiazepines but through a different site. 

Thomsen, C. and Ebert, B. (2002) Modulators of the GABAA receptor complex novel therapeutic aspects, in Glutamate and GABA Receptors and Transporters (Egebjerg, J., Schous-boe, A., and Krogsgaard-Larsen, P., eds.), Taylor Francis, London, pp. 407 127. 

Ugarte, S. D., Homanics, G. E Firestone, L. L and Hammond, D. L. (2000) Sensory thresholds and the antinociceptive effects of GABA receptor agonists in mice lacking the P3 subunit of the GABAa receptor. Neuroscience 95,795-806. 

Fig. 1. Structures of GABA, some GABAa receptor agonists (upper part) and antagonists (lower part).

GABAa receptors. Furthermore, applied GABA hyperpolarizes the post-synaptic neuron, and this response can be blocked reversibly by bicucul-line, indicating that bicuculline directly blocks the GABA receptors. Such GABAergic synaptic transmission is essential to the enhanced ability of the specialized AL PNs to follow intermittent pheromonal stimuli (77). 

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