Regulation of [3H]5-HT release in raphe, frontal cortex and hippocampus of 5-HT1B knock-out mice.
Regulation of the electrically evoked release of [3H]5-HT was examined in midbrain, frontal cortex and hippocampus preloaded slices obtained from wild-type and 5-HT1B knock-out mice. In the absence of any drug [3H]5-HT released was increased in midbrain and hippocampus but not in frontal cortex slices of [3H]5-HT1B knock out mice. The selective 5-HT1B agonist CP 93129 and the 5-HT1B/1D agonist sumatriptan, inhibited [3H]5-HT release in hippocampus and cortical slices obtained from control mice but had no effect in mutants. In the two projection areas studied, the non-selective 5-HT agonist 5-carboxyamidotryptamine (5-CT) inhibited [3H]5-HT release in both groups of mice, indicating that additional 5-HT receptors, other than 5-HT1B, might be involved in the regulation of [3H]5-HT release from 5-HT terminals. In slices containing midbrain raphe nuclei, CP 93129 had no effect in either group. In contrast, sumatriptan inhibited [3H]5-HT release in controls and mutants. The latter effect was blocked by the 5-HT1D antagonist GR 127935, but not the 5-HT1A antagonist (+)WAY 100135, thus suggesting that a 5-HT1D-like receptor, possibly 5-HT1D alpha, negatively regulates 5-HT release in mouse midbrain raphe nuclei.
Piñeyro
G
G
Neurobiological Psychiatry Unit, McGill University, Montreal, Quebec, Canada.
Castanon
N
N
Hen
R
R
Blier
P
P
D000818:Animals; D004558:Electric Stimulation; D005260:Female; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D011903:Raphe Nuclei / Q000187:drug effects / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D014316:Tritium
D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D014316:Tritium; D012701:Serotonin