Mapping Brain Glutamate in Humans: Sex Differences in Cigarette Smokers

The proposed study evaluated sex differences in glutamate (Glu), with a focus on the dorsal anterior cingulate cortex (dACC), anterior insula, and thalamus, as well as how it is influenced by sex (males vs. females), smoking state (overnight abstinent vs. sated), and circulating ovarian hormones (estrogen and progesterone) in women. Glu was measured in the entire brain with special focus on the dorsal anterior cingulate cortex (dACC), anterior insula, and thalamus, all of which have been implicated in tobacco withdrawal, using an echo-planar spectroscopic imaging (EPSI) variant of magnetic resonance spectroscopy (MRS). Serum ovarian hormones (estrogen and progesterone) were measured for female participants to determine relationships between brain Glu and this hormone. Glu was be measured in smokers after overnight (\~12 h) abstinence and after participants smoked the first cigarette of the day.