Abstract
GABAAreceptor mediated two inhibition models, phasic and tonic. Midazolam, benzodiazepine, and a widely used anesthetic, propofol potentiate GABAA receptor function. Bai et al. reported propofol, compared with midazolam, had a lower potency but higher efficacy for increasing the amplitude of the tonic current in the hippocampal CA1 pyramidal neurons. We compared the effect of midazolam and propofol on the tonic current in neocortex layer V pyramidal neuronsusing whole-cell patch clam techniques from 2- to 3- week old rats. Propofol and midazolam cause a concentration-dependent increase in the amplitude of the tonic current. In the neocortex, midazolam increased tonic current more than propofol. Picrotoxin blocked both midazolam and propofol effect on the tonic current. In contrast, bicuculline blocked tonic current induced by midazolam but not proporol. These suggest that these two drugs mediate tonic current via different subtypes of GABAA receptors Referance (1)Molecular Pharmacology 2001;59:814-824 [J Physiol Sci. 2006;56 Suppl:S164]
