Effects of zolpidem on local cerebral glucose metabolism during non-REM sleep in normal volunteers: A positron emission tomography study

Using positron emission tomography with fluorodeoxyglucose (¹⁸FDG or FDG), we compared the effects of zolpidem (10 mg), an imidazopyridine hypnotic, which is relatively selective for the BZ₁ or omega receptor and placebo on cerebral glucose metabolism during the first non-REM sleep period of 12 young normal volunteers, Plasma zolpidem pharmacokinetics varied considerably among subjects, and plasma concentrations were lower than usually reported. In general, the effects of zolpidem on local cerebral glucose metabolism varied directly with plasma concentrations of zolpidem. Zolpidem induced changes in local cerebral glucose metabolism were unevenly distributed throughout the brain and were greater in subcorticnl areas than lateral cortical areas. Significnnt negative correlations were found between change in local absolute glucose metabolic rate (calculated by subtracting individual data on placebo nights from that on zolpidem nights) and plasma concentration of zolpidem for the following areas: medial frontal cortex, cingulate gyrus, putamen, thalamus, and hippocampus. The effects of zolpidem on local cerebral glucose metabolism were partially but nor closely related to the reported density of BZ₁ receptors.