Laminar distribution of serotonergic innervation in rat somatosensory cortex, as determined by in vivo electrochemical detection.

In vivo differential pulse voltammetry was used for the detection of indoleamines during vertical electrode penetrations in rat first somatosensory cortex, for studying the laminar distribution of serotonin and/or its metabolites in that part of the cortex. The peak of current corresponding to 5-hydroxyindoles was maximum in the most superficial part of the cortex and diminished gradually in the deeper layers. These results suggest that the cortical serotonergic innervation is predominant in the superficial layers.