Possible Interaction: Adrenergic Beta-Antagonists and Gamma-Aminobutyric Acid

“Both blockers antagonized the QO2 reducing effect of the combination of per se effective doses of midazolam (1.0 mg/kg) and GABA (5 x 10(-4) mol/l), as well as of GABA (5 x 10(-4) mol/l) itself.”

“These blockers all antagonised the action of GABA at concentrations similar to those required to block synaptic inhibition.”

“These amino acids induced release of GABA was strongly inhibited by the glutamate uptake blocker , pyrrolidine-2,4-dicarboxylate (2,4,PDC) (50 μM), while it was not inhibited by the specific GABA uptake blockers nipecotic acid (0.5 mM) or NO-711 (5μM).”

“Although GYKI appeared to block excitation completely, suggesting an absence of N-methyl-d-aspartate (NMDA)-mediated responses, it was found that in the presence of ionotropic gamma-aminobutyric acid (GABA) blockers , the excitatory postsynaptic potential (EPSP) was prolonged.”

“The beta blockers elevated GABA turnover in the hypothalamus and the pons-medulla.”

“Different uptake blockers inhibited the Ca(2+)-independent translocation of [3H]GABA in both directions with similar specificities.”

“Multiplicity of GABA transporters was indicated in the time-dependent inhibition of [3H]GABA influx by different uptake blockers.”

“After pretreatment with either alpha 1-adrenergic (prazosin) or alpha 2-adrenergic (yohimbine) blocking agents , the inhibitory effect of GABA on ACTH secretion was prevented.”

“Somatic … uptake blockers nipecotic acid or guvacine consistently produced: an … the effectiveness of the inhibition produced by gamma-aminobutyric acid and its analogues: a decrease in the latency to peak of the inhibition and an … the time to recovery; a full blockade of the fade and the "off" response.”

“ Blockers of the catabolism of GABA, such as aminooxyacetic acid and gamma-acetylenic GABA, increase GABA levels and decrease those of GHB.”

“Nipecotic acid, guvacine, and …-diaminopropionic acid, blockers of GABA uptake processes, had essentially no effect by themselves on the SRN membrane input … up to 5 mM, however, they potentiated the effects of sub-maximal concentrations of GABA and decreased the steepness of the … curve, and consequently nH, for GABA.”