Development of the human motor-related thalamic nuclei during the first half of gestation, with special emphasis on GABAergic circuits.
This study analyzed the expression of differentiation markers (Calbindin D28K: CaBP; parvalbumin: PARV; calretinin: CalR), gamma-aminobutyric acid (GABA) markers (GABA, glutamic acid decarboxylases: GAD65, GAD67; and GABA transporters: GAT1, GAT3), and other markers (neurotensin: NT, and neurofilament-specific protein: SMI32) in the human thalamus at 8-23 gestation weeks (g.w.), focusing on the motor-related nuclei. From 8-13 g.w. mainly CaBP was expressed in the cells while fiber bundles traversing the thalamus in addition to CaBP expressed all GABA markers except GAD67. CaBP and PARV expression patterns in different nuclei changed over the time course studied, whereas NT was expressed consistently along the anterior-lateral curvature of the thalamus. CalR and SMI were detectable at 23 g.w. in the ventral parts of the dorsal thalamus. Most remarkably, punctate GAD65 immunoreactivity in the neuropil was confined to the nigro- and pallidothalamic afferent receiving nuclei from 16 to about 21 g.w., overlapping with that of CaBP in some of these nuclei (subdivisions of the ventral anterior and mediodorsal nuclei) and with PARV in others (centromedian nucleus). During this period, GAD65 immunoreactivity can be considered a marker of the basal ganglia afferent receiving territory in the motor thalamus. GAD67-positive local circuit neurons were first detected at 12-13 g.w. in the thalamic nuclei outside the basal ganglia afferent receiving territory. In the ventral anterior and centromedian nuclei, GAD-containing local circuit neurons were not conspicuous even at 22-23 g.w. The cells of the reticular nucleus expressed GAD67 and PARV from 12 g.w. on starting in the lateral-posterior regions. By 23 g.w., both markers were expressed in about two-thirds of the nucleus except for its most medial-anterior part. The results imply spatially and temporally differential expression of GABA and differentiation markers in the developing human thalamus.
Institut National de la Santé et de la Recherche Médicale, U.106, Hôpital Salpetrière, 47 Blvd. de l'Hôpital, Paris, Cedex 13, France.
Kristy
K
Kultas-Ilinsky
Catherine
C
Fallet
Catherine
C
Verney
D015415:Biomarkers / Q000032:analysis; D064092:Calbindin 1; D064032:Calbindin 2; D064026:Calbindins; D002454:Cell Differentiation / Q000502:physiology; D005314:Embryonic and Fetal Development; D050485:GABA Plasma Membrane Transport Proteins; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D026901:Membrane Transport Proteins / Q000378:metabolism; D009046:Motor Neurons / Q000166:cytology* / Q000378:metabolism*; D009434:Neural Pathways / Q000196:embryology / Q000378:metabolism; D016900:Neurofilament Proteins / Q000235:genetics / Q000378:metabolism; D009496:Neurotensin / Q000235:genetics / Q000378:metabolism; D010320:Parvalbumins / Q000235:genetics / Q000378:metabolism; D064030:S100 Calcium Binding Protein G / Q000235:genetics / Q000378:metabolism; D013787:Thalamic Nuclei / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000235:genetics / Q000378:metabolism*
D015415:Biomarkers; C576498:CALB1 protein, human; C576764:CALB2 protein, human; D064092:Calbindin 1; D064032:Calbindin 2; D064026:Calbindins; D050485:GABA Plasma Membrane Transport Proteins; D026901:Membrane Transport Proteins; D016900:Neurofilament Proteins; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G; C493413:SLC6A1 protein, human; C493416:SLC6A11 protein, human; D009496:Neurotensin; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase