Sexual arousal modifies brain metabolites

The levels of several metabolites in the female brain are altered during sexual stimulation induced by watching erotic video clips, a functional MRI study has revealed. Gwang-Woo Jeong and colleagues from Chonnam National University Medical School in Gwangju, Republic of Korea, took measurements in the anterior cingulate gyrus region of the brain, which is commonly associated with sexual drive, arousal and romantic love, as they reported in the Journal of Sexual Medicine.

The concentrations of α-glutamine/glutamate, β.γ-glutamine/glutamate, choline and lactate all increased during sexual stimulation and returned to their normal equilibrium levels soon after stimulation ended. The first three metabolites are all associated with neurotransmission and the researchers suggested that the increases are due to enhanced transmission signalling of excitatory neurotransmitters.

The rise in lactate is consistent with the recently reported view that it is a source of fuel in neurons. Indeed, lactate might be used as an index for the energy source of neuronal activation.

Although the data are preliminary and there were some limitations in the study, like the wide age range of the subjects (21-51) and the restriction to one area of the brain, the study shows that fMRI could be a useful means of examining the neural mechanism associated with sexual arousal.