LAMINAR DISTRIBUTION OF THE MULTIPLE OPIOID RECEPTORS IN THE HUMAN CEREBRAL-CORTEX

Quantitative autoradiographic assessment of cerebral cortical laminar distribution of mu, delta and kappa opioid receptors was carried out i n coronal sections of five post-mortem human brains obtained at autops y. The cortical areas studied were: cingulate, frontal, insular, parie tal, parahippocampal, temporal occipitotemporal, occipital and striate area. In general, the laminar patterns of distribution for the three types of receptors are distinctive. Peak levels of delta opioid bindin g are in laminae I, II, and IIIa. mu-Receptors are located in lamina I II followed by I and II in cingulate, frontal, insular and parietal co rtices and lamina IV in temporal and occiptotemporal cortices. kappa-R eceptors are found concentrated in laminae V and VI. The patterns of o pioid binding in cortical laminae showed remarkable consistency in all five brains examined. In contrast to other cortical areas, the parahi ppocampal gyrus, at the level of the amygdaloid formation, demonstrate d peak kappa receptor density in laminae I, II and III. mu-Opioid bind ing was undetectable in the lateral occipital cortex and in the striat e area.