Expression and anatomical distribution of TrkB in the encephalon of the adult zebrafish (Danio rerio).
Neurotrophins are a family of growth factor primarily acting in the nervous system, throughout two categories of membrane receptors on the basis of their high (Trk receptors) or low (p75NTR) affinity. Both neurotrophins and Trk receptors are phylogenetically conserved and are expressed not only in the central and peripheral nervous system but also in non-nervous tissues of vertebrates and some invertebrates. The brain-derived neurotrophic factor (BDNF)/TrkB system plays an important role in the development, phenotypic maintenance and plasticity of specific neuronal populations. Considering that this system is poorly characterized in the central nervous system of teleosts, the expression and anatomical distribution of TrkB in the brain of the adult zebrafish using reverse transcriptase-polymerase chain reaction (RT-PCR), Western-blot and immunohistochemistry were analysed. Both the riboprobe and the antibody used were designed to map within the catalytic domain of TrkB. RT-PCR detected specific TrkB mRNA in brain homogenates, while Western-blot identified one unique protein band with an estimated molecular weight of 145kDa, thus corresponding with the TrkB full-length isiform of the receptor. Immunohistochemistry showed specific TrkB immunoreactivity in restricted areas of the encephalon, i.e. the hypothalamus and a specific neuronal subpopulation of the reticular formation. The present results demonstrate, for the first time, that, as in mammals, the encephalon of adult zebrafish expresses TrkB in specific zones related to food intake, behaviour or motor activity.
Department of Veterinary Science, University of Messina, Italy.
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F
Abbate
Department of Veterinary Science, University of Messina, Italy.
M C
MC
Guerrera
Department of Veterinary Science, University of Messina, Italy.
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G
Montalbano
Department of Veterinary Science, University of Messina, Italy.
M B
MB
Levanti
Department of Veterinary Science, University of Messina, Italy.
G P
GP
Germanà
Department of Drug Sciences and Health Products, University of Messina, Messina, Italy; IRCCS centro neurolesi "Bonino-Pulejo", Messina, Italy.
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Navarra
Department of Veterinary Science, University of Messina, Italy.
R
R
Laurà
Departmento de Morfología y Biología Celular, Universidad de Oviedo, Spain.
J A
JA
Vega
Department of Veterinary Science, University of Messina, Italy.
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E
Ciriaco
Department of Veterinary Science, University of Messina, Italy; Zebrafish Neuromorphology Lab, University of Messina, Italy. Electronic address: agermana@unime.it.
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A
Germanà
D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D009928:Organ Specificity; D020813:Receptor, trkB / Q000378:metabolism*; D015027:Zebrafish / Q000378:metabolism*
D020813:Receptor, trkB
Brain; Neutrophins; TrkB; Zebrafish