title: Double bouquet cell axons in the human temporal neocortex: relationship to bundles of myelinated axons and colocalization of calretinin and calbindin D-28k immunoreactivities.
abstract: We have examined the distribution of double bouquet cell axons, immunocytochemically stained for the calcium-binding proteins calretinin and calbindin D-28k in the human temporal neocortex, in relation to bundles of myelinated axons (originating from pyramidal cells) and the colocalization of these calcium-binding proteins. The large number and regularity of distribution of double bouquet cell axons was clearly visualized in tangential sections from cortical layers III--V. In these sections, we estimated that the mean number +/- standard deviation of double bouquet cell axons per 10,000 microns2 was 11.65 +/- 0.44 with a mean diameter of 12.10 +/- 0.63 microns and a mean center-to-center spacing of 29.8 +/- 0.91 microns. These values are very similar to those previously reported in the monkey neocortex. The distribution of double bouquet cell axons was closely related to bundles of myelinated axons; there was overlapping with basically a one-to-one correspondence. Finally, double-label immunofluorescence experiments revealed that the vast majority of double bouquet cell axons immunoreactive for calbindin were also stained for calretinin. Since relatively few cell somata were double-labeled in the human temporal cortex, we concluded that double bouquet cells may represent a significant subpopulation of neurons that colocalize these calcium-binding proteins.
authors.affiliation: Instituto Cajal (CSIC), Madrid, Spain.
authors.forename: M R
authors.initials: MR
authors.lastname: del Rio
authors.forename: J
authors.initials: J
authors.lastname: DeFelipe
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001369:Axons / Q000737:chemistry*; D064032:Calbindin 2; D064026:Calbindins; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D018613:Microscopy, Confocal; D019579:Neocortex / Q000737:chemistry / Q000166:cytology*; D009413:Nerve Fibers, Myelinated / Q000737:chemistry; D009419:Nerve Tissue Proteins / Q000032:analysis*; D011817:Rabbits; D064030:S100 Calcium Binding Protein G / Q000032:analysis*; D013702:Temporal Lobe / Q000737:chemistry / Q000166:cytology*
chemical_list: C576764:CALB2 protein, human; C576511:Calb2 protein, mouse; D064032:Calbindin 2; D064026:Calbindins; D009419:Nerve Tissue Proteins; D064030:S100 Calcium Binding Protein G