Chemically defined neuron groups and their subpopulations in the glomerular layer of the rat main olfactory bulb.
Chemically-defined neuron groups and their subpopulations in the glomerular layer of the rat main olfactory bulb were revealed immunocytochemically using antibodies against gamma-amino butyric acid (GABA), tyrosine hydroxylase (TH), methionin-enkephalin-Arg6-Gly7-Leu8 (ENK), calretinin (CR), calbindin-D28K (calbindin) and thyrotropin-releasing hormone (TRH). GABA-like immunoreactive (GABA-LIR) neurons and CR immunoreactive (CR-IR) neurons were most numerous; they were about 1.5-3 times more numerous than calbindin immunoreactive (calbindin-IR), TH immunoreactive (TH-IR), ENK-like immunoreactive (ENK-LIR) and THR-like immunoreactive (TRH-LIR) neurons. We identified at least three distinct chemically-defined neuron groups, GABA-LIR neurons, CR containing neurons and calbindin containing neurons, since these three neuron groups were almost separate from one another. On the other hand, TH-IR and ENK-LIR neurons were nearly included in and thus considered to be subpopulations of GABA-LIR and CR-IR neurons, respectively, for about 80% of these two neuron groups contained GABA-L and CR immunoreactivities, respectively. TRH-LIR neurons appeared to be divided into two subpopulations, one containing the GABA-L immunoreactivity and the other containing the CR immunoreactivity. Thus in the glomerular layer of the rat olfactory bulb, GABA-LIR, CR-IR and calbindin-IR cells could be considered to be three distinct chemically-defined neuron groups, whereas TH-IR, TRH-LIR and ENK-LIR neurons were regarded as their subpopulations. Furthermore, some neurons groups, whereas TH-IR, TRH-LIR and ENK-LIR neurons were regarded as their subpopulations. Furthermore, some neurons are supposed to contain three substances (e.g. GABA + TH + TRH, GABA + TRH + EnK, CR + TRH + ENK, GABA + TRH + CR) or a few might even contain four substances (e.g. GABA + TRH + CR + ENK). Preliminary quantitative analysis using the optical disector method showed percentages of these three main neuron groups to total cells in the glomerular layer; that is, neuron groups containing GABA, CR and calbindin were about 20%, 20% and 10%, respectively.
Kosaka
K
K
Department of Anatomy and Neurobiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Aika
Y
Y
Toida
K
K
Heizmann
C W
CW
Hunziker
W
W
Jacobowitz
D M
DM
Nagatsu
I
I
Streit
P
P
Visser
T J
TJ
Kosaka
T
T
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D002452:Cell Count; D007150:Immunohistochemistry; D008297:Male; D018613:Microscopy, Confocal; D009474:Neurons / Q000145:classification* / Q000276:immunology*; D009830:Olfactory Bulb / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013973:Thyrotropin-Releasing Hormone / Q000276:immunology; D014446:Tyrosine 3-Monooxygenase / Q000276:immunology; D005680:gamma-Aminobutyric Acid / Q000276:immunology
D000906:Antibodies; D005680:gamma-Aminobutyric Acid; D013973:Thyrotropin-Releasing Hormone; D014446:Tyrosine 3-Monooxygenase