GABA action

Yamada, J., Okabe, A., Toyoda, H., Kilb, W., Luhmann, H. J. and Fukuda, A. CT uptake promoting depolarizing GABA actions in immature rat neocortical neurones is mediated by NKCC1. J. Physiol. 557 829-841, 2004. 

The answer is c. (Hardman, p 481. Katzung, pp 404-405.) Vigabatrin is useful in partial seizures. It is an irreversible inhibitor of GABA aminotransferase, an enzyme responsible for the termination of GABA action. This results in accumulation of GABA at synaptic sites, thereby enhancing its effect. 

Guerciohni R, Szumlanski C, Weinshilboum RM Human liver xanthine oxidase nature and extent of individual variation. Chn Pharmacol Ther 50 663-672, 1991 Guisti P, Ducic I, Puia G, et al Imidazenil a new partial positive allosteric modulator of gamma-amniobutyiic acid (GABA) action of GABAa receptors. J Pharmacol Exp Ther 266 1018-1028, 1993... 

Barbiturates are thought to interfere with sodium and potassium transport across cell membranes. This leads to inhibition of the mesencephalic reticular activating system. Polysynaptic transmission is inhibited in all areas of the CNS. Barbiturates also potentiate GABA action on chloride entry into the neuron, although they do not bind at the benzodiazepine receptor. 

Valproic acid [val PROE ic] reduces the propagation of abnormal electrical discharge in the brain. It may enhance GABA action at inhibitory synapses. Valproic acid is the most effective agent avail-... 

Fig. 19.4 Schematic representation of the GABA, -benzodiazepine (B2D) receptor complex. Note that drugs that bind to the benzodiazepine (B2D) receptor site do not open the chloride channel directly but rather augment the capacity of GABA to do so. Conversely agents such as the barbiturates at lov er doses enhance GABA action but at higher doses act directly to open the chloride channel.

Benzodiazepines facilitate GABA actions at GABAa receptors. 

Baclofen facilitates GABA actions by acting as a direct agonist at GABAfi receptors in the spinal cord. The drug is as effective as diazepam in musde spasticity but causes much less sedation. 

Baclofen facilitates GABA actions by acting as a direct agonist at GABAg receptors in the spinal cord. 

Facilitation of GABA actions on chloride ion cheinnels Glutamate receptor antagonism Inhibition of GABA transaminase... 

Which of the following drugs enhances GABA actions on the neuromuscular junctions of nematodes and arthropods ... 

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