title: Neurones in the adult rat anterior medullary velum.
abstract: The presence of neurones in the rat anterior medullary velum (AMV) has been investigated by using antibodies to the calcium-binding proteins, parvalbumin (PV), calretinin (CR), and calbindin-D28k (CB). Disparate populations of mainly GABAergic neurones were located in the rostral and caudal regions of the AMV. The rostral region of the AMV was characterised by GABAergic CR-labelled or PV-labelled neurones. CR-labelled neurones were bipolar or multipolar with round to ovoid somata (diameters between 8 and 12 microm), and rostrocaudally running dendrites forming a network. PV-labelled neurones had round somata (diameters between 6 and 10 microm) and were bi-tufted, with beaded dendrites. Both CR-labelled and PV-labelled dendrites formed punctate pericellular associations with unlabelled somatic profiles. In the caudal region of the AMV, PV-labelled neurones were GABAergic, multipolar cells, having round somata (diameters between 9 and 12 microm), with either beaded or nonbeaded dendrites forming a network of interconnecting dendrites. PV-labelled pericellular associations were made around both PV-labelled and unlabelled somatic profiles. CR labelled unipolar brush cells (UBCs) were not GABAergic. UBCs were characterised by a round to oval somata (10-15 microm in diameter) from which a single primary dendrite emerged to form a distal expansion having small terminal dendrites. From the distal expansion, there also appeared to be CR-labelled processes emanating and extending for up to 250 microm. CB occasionally labelled "Purkinje-like cells" (PLCs). The rat AMV is a more complex structure than first envisaged with the presence of predominantly inhibitory neurones expressing different calcium-binding proteins. Functional and anatomic aspects of this circuitry are further discussed.
authors.affiliation: Institute of Histology and General Embryology, CH-1705 Fribourg, Switzerland. Merdol.Ibrahim@unifr.ch
authors.forename: M
authors.initials: M
authors.lastname: Ibrahim
authors.forename: P A
authors.initials: PA
authors.lastname: Menoud
authors.forename: M R
authors.initials: MR
authors.lastname: Celio
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000737:chemistry* / Q000166:cytology*; D064092:Calbindin 1; D064032:Calbindin 2; D064026:Calbindins; D020546:Fourth Ventricle / Q000737:chemistry* / Q000166:cytology*; D005968:Glutamate Decarboxylase / Q000032:analysis; D008297:Male; D009474:Neurons / Q000737:chemistry* / Q000166:cytology*; D010320:Parvalbumins / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D064030:S100 Calcium Binding Protein G / Q000032:analysis
chemical_list: C576500:Calb1 protein, rat; C576512:Calb2 protein, rat; D064092:Calbindin 1; D064032:Calbindin 2; D064026:Calbindins; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G; D005968:Glutamate Decarboxylase