Original scientific paper
https://doi.org/10.3325/cmj.2019.60.352
Glutamatergic activation of A1 and A2 noradrenergic neurons in the rat brain stem
Duygu Gok-Yurtseven
; Department of Histology and Embryology, Institute of Health Science, Bursa Uludag University, Bursa, Turkey
Ilker M. Kafa
; Department of Anatomy, Bursa Uludag University Faculty of Medicine, Bursa, Turkey
Zehra Minbay
; Department of Histology and Embryology, Bursa Uludag University Faculty of Medicine, Bursa, Turkey
Ozhan Eyigor
; Department of Histology and Embryology, Bursa Uludag University Faculty of Medicine, Bursa, Turkey
Abstract
Aim To analyze the effects of glutamatergic agonists and
antagonists on the activation of the A1 and A2 noradrenergic
neurons localized in caudal ventrolateral medulla and
nucleus tractus solitarii, respectively.
Methods Rats were injected with glutamatergic agonists
– kainic acid, α-amino-3-hydroxy-5-methyl-4-
isoxazolepropionic acid (AMPA), or N-methyl-D-aspartic
acid (NMDA), and the brain sections were prepared for
immunohistochemistry. Before agonist injections, antagonists
– 6-cyano-7-nitroquinoxaline-2,3-dione or dizocilpine
were administered. The expression of c-Fos, as the neuronal
activation marker, and tyrosine hydroxylase (TH), as the
marker of noradrenergic neurons was assessed with dual
immunohistochemistry. The percentage of c-Fos-positive
noradrenergic neurons relative to all TH-positive neurons
in the respective areas of the brain stem was calculated. Results All three glutamatergic agonists significantly increased
the number of the c-Fos-positive noradrenergic
neurons in both the A1 and A2 area when compared with
control animals. Kainic acid injection activated about 57%
of TH-positive neurons in A1 and 40% in A2, AMPA activated
26% in A1 and 38% in A2, and NMDA 77% in A1 and
22% in A2. The injections of appropriate glutamatergic antagonists
greatly decreased the number of activated noradrenergic
neurons.
Conclusion Our results suggest that noradrenergic neurons
are regulated and/or activated by glutamatergic system
and that these neurons express functional glutamate
receptors.
Keywords
Hrčak ID:
240101
URI
Publication date:
15.8.2019.
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