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Regional distribution and cellular localization of 5‐HT 2C receptor mRNA in monkey brain: Comparison with [ 3 H]mesulergine binding sites and choline acetyltransferase mRNA
Author(s) -
LópezGiménez Juan F.,
Mengod Guadalupe,
Palacios José M.,
Vilaró M. Teresa
Publication year - 2001
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.1095
Subject(s) - colocalization , biology , in situ hybridization , striatum , basal forebrain , choline acetyltransferase , nucleus accumbens , basal ganglia , cerebrum , microbiology and biotechnology , messenger rna , receptor , endocrinology , cholinergic , dopamine , central nervous system , biochemistry , gene
The distribution of serotonin 5‐HT 2C receptor mRNA in monkey brain was studied by in situ hybridization and compared with the distribution of [ 3 H]mesulergine binding sites as visualized by receptor autoradiography. 5‐HT 2C receptor transcripts showed a widespread and heterogeneous distribution. The strongest hybridization signal was detected in choroid plexus. In neocortex, 5‐HT 2C mRNA was detected in layer V of all cortical regions examined except in the calcarine sulcus, which was devoid of signal. Several structures within the striatum and basal forebrain were strongly labeled: nucleus accumbens, ventral aspects of anterior caudate and putamen, septal nuclei, diagonal band, ventral striatum, and extended amygdala. Several thalamic, midbrain, and brainstem nuclei also contained 5‐HT 2C mRNA. Comparison of the distributions of 5‐HT 2C mRNA and specific [ 3 H]mesulergine binding sites showed a good agreement in the majority of brain regions, suggesting a predominant somatodendritic localization of 5‐HT 2C receptors. A possible localization to axon terminals of 5‐HT 2C receptors is suggested by the disagreement observed in some regions such as septal nuclei and horizontal limb of the diagonal band (presence of mRNA with apparent absence of binding sites) and interpeduncular nucleus (presence of binding sites with apparent absence of mRNA). Comparison of 5‐HT 2C receptor and choline acetyltransferase mRNA distributions indicate that some regions where cholinergic cells are located are also enriched in cells containing 5‐HT 2C mRNA. Although the present methodology does not allow strict colocalization of both mRNA species to the same cells, the codistribution observed in several regions provides a possible anatomical substrate for the described modulation of acetylcholine release by 5‐HT 2C receptors. Synapse 42:12–26, 2001. © 2001 Wiley‐Liss, Inc.