Article date: 1992/3/13
PubMed ID: 1387031
Journal name: Brain research (ISSN: 0006-8993)
Relative to dopaminergic innervation of cortex, dopamine D1 and D2 receptors may be located on presynaptic terminals and/or postsynaptically on cortical neurons. To assess the relative distribution of these sites, quantitative in vitro receptor autoradiography was performed following injection of 6-hydroxydopamine (6-OHDA) into the median forebrain bundle (MFB; which lesions presynaptic DA terminals) and ibotenic acid into the prefrontal and anterior cingulate cortices (which lesions neurons whose cell bodies are intrinsic to cortex). Receptor autoradiography was performed ten days after injection of neurotoxins with [3H]SCH 23390 (a D1 probe) and [125I]epidepride (a D2 probe). Both DA receptor subtypes were found in all layers of anterior cingulate and prefrontal cortices but were concentrated in deeper layers V and VI. Ibotenic acid lesion of cortex reduced D1 and D2 receptors by 55-80%, although the concentrations of DA and its major metabolite dihydroxyphenylacetic acid (DOPAC) were unchanged. Lesion of MFB produced no significant change in D1 and D2 receptors, but was associated with a 49-52% decrease in DA and DOPAC levels relative to the contralateral side. These results suggest that the majority of D1 and D2 receptors in prefrontal and anterior cingulate cortices are located postsynaptically on neurons intrinsic to the cortex.
Author List: al-Tikriti M S, Roth R H, Kessler R M, Innis R B
Publication Types: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Receptors, Dopamine; Receptors, Dopamine D1; Receptors, Dopamine D2; 3,4-Dihydroxyphenylacetic Acid; Ibotenic Acid; Oxidopamine; Dopamine;
Mesh terms: 3,4-Dihydroxyphenylacetic Acid/metabolism; Animals; Autoradiography; Binding Sites/physiology; Cerebral Cortex/chemistry; Dopamine/metabolism; Ibotenic Acid; Male; Oxidopamine; Radioligand Assay; Rats; Rats, Inbred Strains; Receptors, Dopamine/analysis; Receptors, Dopamine D1; Receptors, Dopamine D2; Synaptosomes/drug effects;