Expression mapping of 5-HT1 serotonin receptor subtypes during fetal and early postnatal mouse forebrain development.
Serotonin (5-HT) is implicated in several aspects of brain development, yet the ontogenetic expression patterns of 5-HT receptors responsible for transducing specific effects have largely not been characterized. Fifteen different 5-HT receptor genes have been cloned; therefore any spatial and/or temporal combination of their developmental expression could mediate a wide array of 5-HT effects. We undertook a detailed analysis of expression mapping of the Gi/o-coupled 5-HT1 (5-HT1A, 1B, 1D and 1F) receptor subtypes in the fetal and early postnatal mouse forebrain. Using receptor subtype-specific riboprobes and in situ hybridization, we observed that all 5-HT1 receptor subtypes are expressed as early as embryonic day (E) 14.5 in the forebrain, typically in gradients within specific structures. Among 5-HT1 receptors, the 5-HT1A receptor transcript is expressed densely in E14.5-16.5 thalamus, in hippocampus, and in a medial to lateral gradient in cortex, whereas the 5-HT1B receptor mRNA is expressed in more lateral parts of the dorsal thalamus and in the striatum at these ages. The 5-HT1D receptor transcript, which also is expressed heavily in E14.5-E16.5 thalamus, appears to be down-regulated at birth. The 5-HT1F receptor transcript is present in proliferative regions such as the cortical ventricular zone, ganglionic eminences, and medial aspects of the thalamus at E14.5-16.5, and otherwise presents similarities to the expression patterns of 5-HT1B and 1D receptor transcripts. Overall, the 5-HT1 subfamily of Gi/o-coupled 5-HT receptors displays specific and dynamic expression patterns during embryonic forebrain development. Moreover, all members of the 5-HT1 receptor class are strongly and transiently expressed in the embryonic dorsal thalamus, which suggests a potential role for serotonin in early thalamic development.
Bonnin
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A
Department of Pharmacology, Vanderbilt University, 8114 MRBIII, 465 21st Avenue South, Nashville, TN 37232-8548, USA; Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Box 40 Peabody, 230 Appleton Place, Nashville, TN 37203, USA.
Peng
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W
Department of Psychiatry, Vanderbilt School of Medicine, 1601 23rd Avenue South, Nashville, TN 37232-8645, USA.
Hewlett
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Department of Psychiatry, Vanderbilt School of Medicine, 1601 23rd Avenue South, Nashville, TN 37232-8645, USA; Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Box 40 Peabody, 230 Appleton Place, Nashville, TN 37203, USA.
Levitt
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P
Department of Pharmacology, Vanderbilt University, 8114 MRBIII, 465 21st Avenue South, Nashville, TN 37232-8548, USA; Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Box 40 Peabody, 230 Appleton Place, Nashville, TN 37203, USA. Electronic address: Pat.Levitt@vanderbilt.edu.
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001931:Brain Mapping; D003952:Diagnostic Imaging / Q000379:methods; D004622:Embryo, Mammalian; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D017403:In Situ Hybridization / Q000379:methods; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D016548:Prosencephalon / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D044282:Receptor, Serotonin, 5-HT1A / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
D021122:Protein Subunits; D012333:RNA, Messenger; D044282:Receptor, Serotonin, 5-HT1A