title: Selective coexpression of multiple chemical markers defines discrete populations of neocortical GABAergic neurons.
abstract: Whether neocortical γ-aminobutyric acid (GABA) cells are composed of a limited number of distinct classes of neuron, or whether they are continuously differentiated with much higher diversity, remains a contentious issue for the field. Most GABA cells of rat frontal cortex have at least 1 of 6 chemical markers (parvalbumin, calretinin, alpha-actinin-2, somatostatin, vasoactive intestinal polypeptide, and cholecystokinin), with each chemical class comprising several distinct neuronal subtypes having specific physiological and morphological characteristics. To better clarify GABAergic neuron diversity, we assessed the colocalization of these 6 chemical markers with corticotropin-releasing factor (CRF), neuropeptide Y (NPY), the substance P receptor (SPR), and nitric oxide synthase (NOS); these 4 additional chemical markers suggested to be expressed diversely or specifically among cortical GABA cells. We further correlated morphological and physiological characteristics of identified some chemical subclasses of inhibitory neurons. Our results reveal expression specificity of CRF, NPY, SPR, and NOS in morphologically and physiologically distinct interneuron classes. These observations support the existence of a limited number of functionally distinct subtypes of GABA cells in the neocortex.
authors.affiliation: Division of Cerebral Circuitry, National Institute for Physiological Sciences, Okazaki 444-8787, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kubota
authors.forename: Naoki
authors.initials: N
authors.lastname: Shigematsu
authors.forename: Fuyuki
authors.initials: F
authors.lastname: Karube
authors.forename: Akio
authors.initials: A
authors.lastname: Sekigawa
authors.forename: Satoko
authors.initials: S
authors.lastname: Kato
authors.forename: Noboru
authors.initials: N
authors.lastname: Yamaguchi
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Hirai
authors.forename: Mieko
authors.initials: M
authors.lastname: Morishima
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kawaguchi
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D005625:Frontal Lobe / Q000166:cytology / Q000378:metabolism; D059330:GABAergic Neurons / Q000145:classification / Q000166:cytology / Q000378:metabolism*; D007395:Interneurons / Q000145:classification / Q000166:cytology / Q000378:metabolism*; D008297:Male; D019579:Neocortex / Q000166:cytology / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D055495:Neurogenesis / Q000502:physiology; D010641:Phenotype; D051381:Rats; D055647:Rats, Transgenic; D017208:Rats, Wistar; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
chemical_list: D015415:Biomarkers; D009419:Nerve Tissue Proteins; D005680:gamma-Aminobutyric Acid