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Tonic Effects and Vascular Reactivity in Rats Submitted to Parkinsonism by Infusion of Bilateral 6‐OHDA in Substantia Nigra
Author(s) -
Ariza Deborah,
Higashi Carolina,
Gameiro Juliana,
Ceravolo Graziela,
Crestani Carlos,
MartinsPinge Marli
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.831.3
Subject(s) - phenylephrine , substantia nigra , prazosin , medicine , parkinsonism , anesthesia , tonic (physiology) , endocrinology , dopamine , chemistry , blood pressure , dopaminergic , receptor , disease , antagonist
We aimed to investigate the cardiovascular changes in an animal model of Parkinsonism. Adult male Wistar rats were anesthetized to receive bilateral microinfusion of 6‐hydroxy dopamine (6‐OHDA) or saline (control) in the substantia nigra. After 7 days, registration of mean arterial pressure (MAP) and heart hate (HR), after α‐adrenergic antagonistwere performed in conscious rats. In another groups of animals the thoracic aorta was removed and sectioned into two rings for vascular reactivity: Endo + (endothelium was kept) and Endo‐ (endothelium removed using a fine cotton swab). Phenylephrine (PHE) cumulative concentration‐effect curves were constructed. After prazosin, 6‐OHDA animals presented a lower decrease in MAP. The PHE promoted concentration‐dependent contraction in aortic rings of both groups. The Rmax was lower in PHE Endo+ rings of 6‐OHDA (2.29 ± 0.13; n = 9) compared to the sham Endo+ (2.74 ± 0.13; n = 8). In Endo‐ rings, both groups, the PHE Rmax was higher as compared to Endo +. However, there was no difference between the sham (3.52 ± 0.18; n = 8) and 6‐OHDA groups (3.02 ± 0.18; n = 9) on the Rmax of Endo‐ rings. The results showed aortic hyporeactivity to PHE, probably due to endothelium‐dependent mechanism. We suggest that 6‐OHDA Parkinsonism decreased sympathetic tone, may be related to α‐adrenergic hyporesponsiveness in blood vessels.