Tyrosine hydroxilase activity in discrete brain regions from prehepatic portal hypertensive rats.
OBJECTIVE
Portal hypertension in patients and rat models are characterized by splanchnic and systemic hemodynamic alterations. Both the central and autonomic nervous systems are implicated in its pathophysiology. The aim of our research was to study the tyrosine hydroxylase activity and the rate limiting step in the biosynthesis of catecholamines in partial ligated portal hypertensive and in control rat brains.


METHODS
The following seven discrete brain regions were investigated: Subfornical Organ, Organum Vasculosum Lamina Terminalis, Median Eminence, Periventricular Nucleus, Area Postrema, Locus Coeruleus and Nucleus Tractus Solitarius.


RESULTS
The enzyme activity showed a significant increment in six nuclei and a decrease in Area Postrema Nucleus when portal hypertensive rats were compared to controls.


CONCLUSIONS
These results suggest the participation of some discrete brain regions in the mechanism of hepatic portal hypertension under the present rat model.
Lemberg
A
A
Catedra de Fisiopatologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires, Argentina.
Rubio
M
M
Bengochea
L
L
Romay
S
S
Eizayaga
F
F
Diez
A
A
Perazzo
J C
JC
D000818:Animals; D001921:Brain / Q000201:enzymology*; D006975:Hypertension, Portal / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000096:biosynthesis; D017082:Portal Pressure; D051381:Rats; D017208:Rats, Wistar; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D014446:Tyrosine 3-Monooxygenase; D009638:Norepinephrine