Human striosomes are enriched in 5-HT2A receptors: autoradiographical visualization with [3H]MDL100,907, [125I](±)DOI and [3H]ketanserin

Authors

  • Juan F. López-Giménez,

    1. Department of Neurochemistry, Instituto de Investigaciones Biomédicas de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), IDIBAPS. Rosselló 161, E-08036 Barcelona, Spain.
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  • Guadalupe Mengod,

    1. Department of Neurochemistry, Instituto de Investigaciones Biomédicas de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), IDIBAPS. Rosselló 161, E-08036 Barcelona, Spain.
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  • José M. Palacios,

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    • *

      *Permanent address: Research Center, Almirall Prodesfarma S.A., Cardener 68-74, E-08024, Barcelona, Spain.

  • M. Teresa Vilaró

    1. Department of Neurochemistry, Instituto de Investigaciones Biomédicas de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), IDIBAPS. Rosselló 161, E-08036 Barcelona, Spain.
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Dr Guadalupe Mengod, as above.
E-mail: gmlnqr@iibb.csic.es

Abstract

5-HT2A receptors have been visualized with [3H]MDL100,907 in selected human brain areas by autoradiography. These areas included caudate and putamen, nucleus dentatus of the cerebellum, substantia nigra, nucleus raphe dorsalis, locus coeruleus and inferior olive. In the striatum [3H]MDL100,907 labelling was compared with the pattern obtained with [125I](±)DOI and [3H]ketanserin. [3H]MDL100,907 and [125I](±)DOI showed an identical patchy distribution which was hardly observed with [3H]ketanserin. In the remaining regions, [3H]MDL100,907 and [3H]ketanserin autoradiographical signals and percentage of specific binding were compared. Whereas the pattern of distribution was identical for both radioligands, [3H]MDL100,907 presented a much lower percentage of nonspecific binding compared with [3H]ketanserin. These results confirm the presence of 5-HT2A receptors in human striosomes and in those areas where [3H]ketanserin presented a high nonspecific binding, and they highlight the advantage of using [3H]MDL100,907 to visualize these receptors.

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