A comparison of the effects of midazolam and pentobarbital on the dose-response of GABA-gated Cl- influx in rat brain microsacs.
gamma-Aminobutyric acid (GABA)-gated Cl- influx was studied in a rat brain 'microsac' preparation. Midazolam (a benzodiazepine), at 0.1-10 microM, increased GABA potency (maximum 2-fold) without affecting its efficacy or exerting GABA-mimetic effect. Pentobarbital (10-500 microM) increased GABA potency (maximum 12-fold) and efficacy (maximum 40%). Pentobarbital exhibited GABA-mimetic effect at concentrations above 200 microM. The differential effects of midazolam and pentobarbital in modulating GABA-mediated responses may account for some of the differences between these two classes of drugs.
Yu
O F
OF
Department of Pharmacology, Medical College Ohio, Toledo 43699.
Chiu
T H
TH
Rosenberg
H C
HC
D000818:Animals; D002712:Chlorides / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007477:Ions; D008297:Male; D008874:Midazolam / Q000494:pharmacology*; D010424:Pentobarbital / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D002712:Chlorides; D007477:Ions; D005680:gamma-Aminobutyric Acid; D010424:Pentobarbital; D008874:Midazolam