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Coexistence of serotonin 3 (5‐HT 3 ) and CB1 cannabinoid receptors in interneurons of hippocampus and dentate gyrus
Author(s) -
Morales Marisela,
Bäckman Cristina
Publication year - 2002
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.10025
Subject(s) - cannabinoid receptor , cannabinoid , neuroscience , serotonergic , dentate gyrus , chemistry , neurotransmission , neurotransmitter , serotonin , 5 ht receptor , depolarization induced suppression of inhibition , hippocampus , receptor , biology , central nervous system , biochemistry , agonist
Using in situ hybridization histochemistry, a high degree of coexpression of the functional 5‐HT 3A subunit of the 5‐HT 3 receptor and the central CB1 cannabinoid receptor was detected in all subfields of the hippocampus and subgranular layer of the dentate gyrus (DG). Semiquantitative analysis demonstrated that, depending on the hippocampal layer, 72–88% of CB1‐expressing interneurons coexpress the 5‐HT 3A subunit. Within the DG, 5‐HT 3A /CB1 double‐labeled neurons were confined to the subgranular layer, where close to 80% of all CB1‐expressing basket neurons were found to contain 5‐HT 3A subunit transcripts. These results provide the first evidence indicating that the only ion channel receptor for serotonin and central CB1 cannabinoid receptor coexist in neurons containing the inhibitory neurotransmitter γ‐aminobutyric acid (GABA). These findings suggest possible interactions between the cannabinoid and serotonergic systems at the level of GABA neurotransmission. However, activation of 5‐HT 3 ‐ or CB1‐receptors are likely to have opposing regulatory effects on GABA neurotransmission, as 5‐HT 3 receptor activation by serotonin results in the release of GABA, while CB1 activation by cannabinoids results in inhibition of GABA release. Hippocampus 2002;12:756–764. © 2002 Wiley‐Liss, Inc.