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GABA B receptors in 5‐HT transporter‐ and 5‐HT 1A receptor‐knock‐out mice: further evidence of a transduction pathway shared with 5‐HT 1A receptors
Author(s) -
La Cour Clotilde Mannoury,
Hanoun Naïma,
Melfort Maxette,
Hen René,
Lesch KlausPeter,
Hamon Michel,
Lanfumey Laurence
Publication year - 2004
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2004.02367.x
Subject(s) - dorsal raphe nucleus , receptor , gabab receptor , 5 ht receptor , autoreceptor , chemistry , agonist , serotonergic , raphe nuclei , stimulation , metabotropic receptor , medicine , endocrinology , serotonin , biology , neuroscience , biochemistry
The functional properties of GABA B receptors were examined in the dorsal raphe nucleus (DRN) and the hippocampus of knock‐out mice devoid of the 5‐HT transporter (5‐HTT–/–) or the 5‐HT 1A receptor (5‐HT 1A –/–). Electrophysiological recordings in brain slices showed that the GABA B receptor agonist baclofen caused a lower hyperpolarization and neuronal firing inhibition of DRN 5‐HT cells in 5‐HTT–/– versus 5‐HTT+/+ mice. In addition, [ 35 S]GTP‐γ‐S binding induced by GABA B receptor stimulation in the DRN was approximately 40% less in these mutants compared with wild‐type mice. In contrast, GABA B receptors appeared functionally intact in the hippocampus of 5‐HTT–/–, and in both this area and the DRN of 5‐HT 1A ‐knock‐out mice. The unique functional changes of DRN GABA B receptors closely resembled those of 5‐HT 1A autoreceptors in 5‐HTT–/– mice, further supporting the idea that both receptor types are coupled to a common pool of G‐proteins in serotoninergic neurons.