ABSTRACT
The identification of endogenous benzodiazepines (BZDs) within the synaptic vesicles located within the human brain was reported in 1986. Subsequently, several such substances (termed “endozepines”) were reported, including peptides, ß-carbolines, and small non-BZDs. Immunocytochemical localization studies point to levels in neurons of the cortex (mainly in limbic structures) and the cerebellum, but also in the periphery (e.g., kidney, liver, and spleen). The concentrations are high enough to suggest a role in the modulation of GABAergic neurotransmission. There is still some debate over their source, however; whether from endogenous synthesis or from exogenous origin (e.g., the diet or environment). Whatever the actual origin, their presence could ostensibly modify an individual’s response (in magnitude or duration) to BZDs (the therapeutic or adverse effects), either during therapy or during withdrawal from them.
