title: Ontogenesis of NADPH-diaphorase positive neurons in guinea pig neocortex.
abstract: In mammalian cerebrum there exist two distinct types of interneurons expressing nitric oxide synthase (NOS). Type I neurons are large in size and exhibit heavy nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemical reaction, while type II cells are small with light NADPH-d reactivity. The time of origin of these cortical neurons relative to corticogenesis remains largely unclear among mammals. Here we explored this issue in guinea pigs using cell birth-dating and double-labeling methods. Bromodeoxyuridine (BrdU) pulse-chasing (2 doses at 50 mg/kg, 12 h apart) was given to time-pregnant mothers, followed by quantification of NADPH-d/BrdU colocalization in the parietal and temporal neocortex in offspring at postnatal day 0 (P0), P30 and P60. Type I neurons were partially colabeled with BrdU at P0, P30 and P60 following pulse-chasing at embryonic day 21 (E21), E28 and E35, varied from 2-11.3% of total population of these neurons for the three time groups. Type II neurons were partially colabeled for BrdU following pulse-chasing at E21, E28, E35 and E42 at P0 (8.6%-16.5% of total population for individual time groups). At P60, type II neurons were found to co-express BrdU (4.8-11.3% of total population for individual time groups) following pulse-chasing at E21, E28, E35, E42, E49, E56 and E60/61. These results indicate that in guinea pigs type I neurons are generated during early corticogenesis, whereas type II cells are produced over a wide prenatal time window persisting until birth. The data also suggest that type II nitrinergic neurons may undergo a period of development/differentiation, for over 1 month, before being NADPH-d reactive.
authors.affiliation: Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science Changsha, China ; Department of Neurology, The First Hospital of Changsha Changsha, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science Changsha, China ; School of Nursing, Xiangtan Vocational and Technical College Xiangtan, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science Changsha, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Hu
authors.affiliation: Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science Changsha, China.
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Li
authors.affiliation: Department of Neurology, The Second Affiliated Hospital, Harbin Medical University Harbin, China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Zhang
authors.affiliation: Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science Changsha, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science Changsha, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science Changsha, China.
authors.forename: Xiao-Xin
authors.initials: XX
authors.lastname: Yan
keywords: GABAergic; corticogenesis; interneuron; neuronal development; nitric oxide