Dopamine autoreceptors modulate the in vivo release of dopamine in the frontal, cingulate and entorhinal cortices

The regulation by autoreceptors of dopamine release in the rat neocortex was inferred from measurements of 3-methoxytyramine after the peripheral injection of a selective (CGS 15855A) or nonselective (apomorphine) dopamine autoreceptor agonist. Basal levels of dopamine release were greatly decreased in the frontal cortex and caudate putamen after the injection of CGS 15855A or apomorphine. The pargyline-induced accumulations of 3-methoxytyramine in the frontal cortex, cingulate cortex and caudate putamen were attenuated by 52 to 82% after the injection of either agonist. 3-Methoxytyramine accumulations in the entorhinal cortex were attenuated by 68% by apomorphine. Thus, as in the caudate putamen, dopamine autoreceptors modulate the in vivo release of dopamine in the frontal cortex and the turnover of the releasable dopamine pool in the frontal, cingulate and entorhinal cortices.