Memory effects of benzodiazepines: Memory stages and types versus binding-site subtypes

Abstract

Benzodiazepines are well established as inhibitory modulators of memory processing. This effect is especially prominent when applied before the acquisition phase of a memory task. This minireview concentrates on the putative subtype selectivity of the acquisition-impairing action of benzodiazepines. Namely, recent genetic studies. and standard behavioral tests employing subtype-selective ligands pointed to the predominant involvement of two subtypes of benzodiazepine binding sites in memory modulation. Explicit memory learning seems to be affected through the GABA A receptors containing the α 1 and α 5 subunits, whereas the effects on procedural memory can be mainly mediated by the α 1 subunit. The pervading involvement of the α 1 subunit in memory modulation is not at all unexpected because this subunit is the major subtype, present in 60% of all GABA A receptors. On the other hand, the role of α 5 subunits, mainly expressed in the hippocampus, in modulating distinct forms of memory gives promise of selective pharmacological coping with certain memory deficit states. © 2005 Freund Publishing House Ltd.