Distribution of dopamine in the rat cerebral cortex.

The rat cerebral neocortex was sectioned by 3 transverse cuts and analyzed for dopamine and noradrenaline. Dopamine concentration decreased gradually from the rostral (97 +/- 4 ng/g) to the caudal (59 +/- 2 ng/g) end of the neocortex. Also, the noradrenaline concentration was highest in the rostral part (269 +/- 6 ng/g) and decreased gradually reaching a concentration of 238 +/- 3 ng/g in the caudal part. Since the quotient dopamine/noradrenaline showed similar changes in the neocortex parts investigated the data support the view that dopamine serves as a transmitter in cortical neurons apart from being a precursor for noradrenaline.