ABSTRACT
Although it has been well established that GABA(A) receptors are molecular targets of a variety of allosteric modulators, such as benzodiazepines, the pharmacological properties of presynaptic GABA(A) receptors are poorly understood. In this study, the effects of diazepam and Zn(2+) on presynaptic GABA(A) receptors have been investigated by measuring the GABA(A) receptor-mediated facilitation of spontaneous glutamate release in mechanically dissociated rat CA3 pyramidal neurons. Diazepam significantly enhanced the muscimol-induced facilitation (particularly at submicromolar concentrations) of spontaneous glutamate release and shifted the concentration-response relationship for muscimol toward the left, whereas Zn(2+) (Subject(s)
Dentate Gyrus/cytology
, Dentate Gyrus/drug effects
, Neurons/drug effects
, Presynaptic Terminals/drug effects
, Receptors, GABA-A/drug effects
, Algorithms
, Animals
, Data Interpretation, Statistical
, Diazepam/pharmacology
, Electrophysiology
, Excitatory Postsynaptic Potentials/drug effects
, GABA Agonists/pharmacology
, GABA Modulators/pharmacology
, Mossy Fibers, Hippocampal/drug effects
, Muscimol/pharmacology
, Patch-Clamp Techniques
, Rats
, Rats, Wistar
, Zinc/pharmacology