Septal co-infusions of glucose with a GABAB agonist impair memory

Septal infusions of glucose exacerbate memory deficits produced by co-infusions of drugs that increase γ-aminobutyric acid (GABA)A receptor activity. To further understand the interaction between glucose and GABA, this experiment tested whether glucose would also potentiate spatial working memory deficits produced by septal infusions of the GABAB receptor agonist baclofen. Fifteen minutes prior to assessing spontaneous alternation (SA), male Sprague–Dawley derived rats were given septal infusions of vehicle, glucose (33 nmol), baclofen (0.1 nmol), or glucose combined with baclofen in one solution. Septal co-infusions of glucose with baclofen, at doses that individually had no effect, significantly impaired SA. Thus, the memory-impairing effects of glucose are observed with either GABAA or GABAB receptor ligands. This raises the possibility that glucose may impair memory by increasing synaptic levels of GABA and subsequent activation of these different receptor subtypes. These effects of glucose could contribute to the memory-impairing effects of hyperglycemia.