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Glutamate and GABA neurotransmission are increased in paraventricular nucleus of hypothalamus in rats induced to 6‐OHDA parkinsonism: Involvement of nNOS
Author(s) -
Turossi Amorim Eric Diego,
de Jager Lorena,
Martins Andressa Busetti,
Rodrigues Ananda Totti,
Cruz Lucchetti Bruno Fernando,
Ariza Deborah,
PingeFilho Phileno,
Crestani Carlos Cesar,
Uchoa Ernane Torres,
MartinsPinge Marli Cardoso
Publication year - 2019
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.13264
Subject(s) - medicine , endocrinology , parkinsonism , pars compacta , substantia nigra , hypothalamus , neurotransmission , dopamine , dopaminergic , receptor , disease
Aim Parkinson's disease (PD) is a progressive neurodegenerative disease that manifests itself clinically after reaching an advanced pathological stage. Besides motor signals, PD patients present cardiovascular and autonomic alterations. Recent data showed that rats induced to Parkinsonism by 6‐hydroxydopamine (6‐OHDA) administration in the substantia nigra pars compacta (SNpc) showed lower mean arterial pressure (MAP) and heart rate (HR), as reduction in sympathetic modulation. The paraventricular nucleus of the hypothalamus (PVN) is an important site for autonomic and cardiovascular control, and amino acid neurotransmission has a central role. We evaluate PVN amino acid neurotransmission in cardiovascular and autonomic effects of 6‐OHDA Parkinsonism. Methods Male Wistar rats were submitted to guide cannulas implantation into the PVN. 6‐OHDA or sterile saline (sham) was administered bilaterally in the SNpc. After 7 days, cardiovascular recordings in conscious state was performed. Results Bicuculline promoted an increase in MAP and HR in sham group and exacerbated those effects in 6‐OHDA group. NBQX (non‐NMDA inhibitor) did not promote changes in sham as in 6‐OHDA group. On the other hand, PVN microinjection of LY235959 (NMDA inhibitor) in sham group did not induced cardiovascular alterations, but decreased MAP and HR in 6‐OHDA group. Compared to Sham group, 6‐OHDA lesion increased the number of neuronal nitric oxide synthase (nNOS)‐immunoreactive neurons in the PVN and, nNOS inhibition promoted higher increases in MAP and HR. Conclusion Our data suggest that the decreased baseline blood pressure and heart rate in animals with Parkinsonism may be due to an increased GABAergic tone via nNOS in the PVN.