Chronic effects of imipramine and lithium on 5-HT receptor subtypes in rat frontal cortex, hippocampus and choroid plexus: quantitative receptor autoradiographic analysis.
The effects of chronic treatment with imipramine or lithium on serotonin (5-HT) receptor subtypes were analyzed in the frontal cortex, hippocampus and choroid plexus of rat brain by quantitative receptor autoradiographic procedures, using radioligands [3H]-5-HT, [3H]-8-hydroxy-2-(di-n-propylamino)tetralin ([3H]-8-OH-DPAT), [125I]-iodocyanopindolol ([125I]-CYP), [3H]-mesulergine and [125I]-7-amino-8-iodo-ketanserin ([125I]-ketanserin) or [3H]-spiperone. Chronic i.p. administration of imipramine (20 mg/kg/day for 21 days) decreased the densities of 5-HT1, 5-HT1A, 5-HT1C and 5-HT2 sites in the frontal cortex, hippocampus and choroid plexus. Lithium (2 mEq/kg/day for 21 days) also decreased the densities of 5-HT1, 5-HT1C and 5-HT2 sites in the frontal cortex, and the densities of those including 5-HT1A sites in the hippocampus and choroid plexus. Imipramine and lithium very markedly decreased the density of 5-HT1C sites in the choroid plexus. We propose that methods employing quantitative receptor autoradiographic analysis can be used to characterize and understand the local effects of these drugs on 5-HT receptor subtypes.
Department of Pharmacology, Institute of Pharmaceutical Sciences, Hiroshima University School of Medicine, Japan.
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Segawa
D000818:Animals; D001345:Autoradiography; D001923:Brain Chemistry / Q000187:drug effects*; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism; D002831:Choroid Plexus / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism; D006624:Hippocampus / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism; D007099:Imipramine / Q000494:pharmacology*; D007457:Iodine Radioisotopes; D007650:Ketanserin / Q000378:metabolism; D008094:Lithium / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D013134:Spiperone / Q000378:metabolism
D007457:Iodine Radioisotopes; D011985:Receptors, Serotonin; D013134:Spiperone; D007650:Ketanserin; D008094:Lithium; D007099:Imipramine