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Cannabinoid CB1 receptor and serotonin 3 receptor subunit A (5‐HT 3A ) are co‐expressed in GABA neurons in the rat telencephalon
Author(s) -
Morales Marisela,
Wang ShwunDe,
DiazRuiz Oscar,
HyunJin Jho Diana
Publication year - 2003
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.10968
Subject(s) - subiculum , biology , cannabinoid receptor , entorhinal cortex , cerebrum , neuroscience , cannabinoid , serotonin , 5 ht receptor , hippocampal formation , serotonergic , neurotransmitter , hippocampus , dentate gyrus , receptor , central nervous system , biochemistry , agonist
Among all described serotonin (5‐HT) receptors in mammals, the type three (5‐HT 3 ) is the only ligand‐gated ion channel receptor for serotonin. By using double in situ hybridization histochemistry, we found co‐expression of the functional 5‐HT 3A subunit of the 5‐HT 3 receptor and the central CB1 cannabinoid receptor in neurons of the rat telencephalon. Double‐labeled 5‐HT 3A /CB1 neurons were found in the anterior olfactory nucleus, superficial and deep layers of the cortex, hippocampal formation (hippocampus, dentate gyrus, subiculum, and entorhinal cortex) and amygdala. Analysis of the proportion of neurons co‐expressing 5‐HT 3A and CB1 receptors in the cortex and amygdala showed that, depending on the brain region, 37–53% of all neurons expressing the 5‐HT 3A subunit also expressed CB1 transcripts; 16–72% of the total population of neurons expressing CB1 mRNA co‐expressed the 5‐HT 3A subunit. By using a combination of double in situ hybridization and immunohistochemistry, we demonstrated that 5‐HT 3A /CB1‐expressing neurons contained the inhibitory neurotransmitter γ‐aminobutyric acid (GABA). These results imply that in distinct regions of the telencephalon, GABA neurons that react to cannabinoids may also be responsive to serotonin through 5‐HT 3 receptors. Cellular coexistence of 5‐HT 3A and CB1 transcripts in interneurons of the cortex, hippocampal formation, and amygdala suggest possible interactions between the cannabinoid and serotonergic systems at the level of GABA neurotransmission in brain areas involved in cognition, memory, and emotion. J. Comp. Neurol. 468:205–216, 2004. Published 2003 Wiley‐Liss, Inc.