INVESTIGADORES
SOMOZA Gustavo Manuel
congresos y reuniones científicas
Título:
Do serotonin and dopamine modulate the neurogenic activity of the caudal hypothalamus in adult zebrafish (Danio rerio)?
Autor/es:
MARÍA R. PÉREZ; COLETTE VAILLANT; GUSTAVO M. SOMOZA; OLIVIER KAH
Lugar:
Lille, France
Reunión:
Congreso; 14th Annual Meeting of the LARC-Neuroscience network.; 2010
Resumen:
The monoamines
(histamine, dopamine, noradrenaline and serotonine) are involved in a variety of
physiological and behavioral processes in vertebrates. In adult mammals, there
are indications that serotonine (5-HT) and dopamine (DA) levels influence
neurogenesis in the hippocampus and subventricular zone. These observations
potentially correlate with neurodegenerative disorders, such as Parkinsons
disease, Alzheimers disease, schizophrenia or depression.
In most
vertebrates, except mammals, the caudal hypothalamic region contains numerous
cerebrospinal fluid (CSF)-contacting neurons that express 5-HT and/or DA. This
so called paraventicular organ (PVO) is extremely developed in fish where such
neurons are found along the the third ventricle and its lateral and posterior
recesses. This area also exhibits a significant proliferative activity and a
high number of aromatase-positive progenitor radial glial cells in adult fish.
This intriguing situation raises the question of the potential functional links
between monoamines, estrogen production and neurogenesis in these regions. In
order to examiner the relationship between the 5-HT and DA in theand
neurogenesis, was we investigated whether alterations in levels of these neurotransmitters are associated with changes in the
proliferation in the caudal hypothalamus in adult zebrafish.
Using immunohistochemistry in cyp19a1b-GFP
(Aromatase B) transgenic zebrafish line, which expresses GFP in radial glial
cells, the precise distribution of the 5-HT and DA expressing cells was
compared with that of aromatase expression in the periventricular cell layers
of the nucleus of the posterior recess (NRP),
the most caudal extension of the diencephalic ventricle. Subsequently,
pharmacological treatments were performed with p-chlorophenylalanine (pCPA),
inhibitor of the tryptophan hydroxylase, the limiting enzyme of 5-HT synthesis,
and pargyline, monoamine oxidase inhibitor able to increase the amount of
dopamine available. Following injection, fish were sacrificed, their brains
removed and fixed for immunohistochemistry processing. Cell proliferation in
the treated and control groups was monitored by counting PCNA positive cells.
Exposure of fish to pCPA decreases the number of ir-PCNA cells. Contrary to
treatment with pargyline there is a growing trend in the number of these cells.
These results,
although preliminary, indicate that 5HT and DA levels can modulate cell
proliferation in the caudal hypothalamus of adult zebrafish.
This work is supported by the University of
Rennes 1, the Université Européenne de Bertagne (France) and CONICET
(Argentina)