Cardiovascular and autonomic alterations in rats with Parkinsonism induced by 6-OHDA and treated with L-DOPA.
OBJECTIVE
Evaluate the effects caused by L-DOPA on cardiovascular and autonomic parameters in an animal model of Parkinsonism induced by 6-hydroxydopamine (6-OHDA).


METHODS
Adult male Wistar rats were subjected to bilateral microinfusion of 6-OHDA or saline (sham group) in the substantia nigra, and treated by gavage with L-DOPA or water for 7 days after surgery. On the 6th day the rats were subjected to femoral artery catheterization for cardiovascular recording. Mean arterial pressure (MAP) and heart rate (HR) were evaluated at baseline and during head up tilt (HUT) protocol. Spectral analysis of cardiovascular variability was performed using the V2.4 CardioSeries software v2.4. The lesion was quantified by dopamine levels in the striatum.


RESULTS
Dopamine levels in the striatum were decreased in 6-OHDA rats (sham: 4.79 ± 0.49 ng/mg; 6-OHDA: 1.99 ± 0.68 ng/mg) and were not recovered by Prolopa treatment. Baseline values of MAP and HR were not different between groups. HUT induced an increase in MAP and HR (ΔMAP: 17 ± 1 mm Hg, ΔHR: 39 ± 4 bpm) that were attenuated in 6-OHDA and in Prolopa treated animals. At baseline, the systolic arterial pressure (SAP) variance was lower in the 6-OHDA AND sham prolopa groups. Spontaneous baroreflex sensitivity was higher at baseline in the 6-OHDA group as compared to all studied groups.


CONCLUSIONS
Our data suggest that treatment with Prolopa did not interfere with cardiovascular variables at baseline. However, during HUT, the 6-OHDA and Prolopa control animals presented a lower cardiovascular compensation, suggesting a possible autonomic impairment in Parkinsonism induced by 6-OHDA.
Departamento de Ciências Fisiológicas, Universidade Estadual de Londrina - UEL, Londrina, PR, Brazil.
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AS
Silva
Departamento de Ciências Fisiológicas, Universidade Estadual de Londrina - UEL, Londrina, PR, Brazil.
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Ariza
Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Fisiologia, Laboratório de Fisiologia Cardiovascular, Ribeirão Preto, SP, Brazil.
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DP
Dias
Faculdade de Ciências Farmacêuticas da Universidade Estadual Paulista (UNESP), Araraquara, SP, Brazil.
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CC
Crestani
Departamento de Ciências Fisiológicas, Universidade Estadual de Londrina - UEL, Londrina, PR, Brazil. Electronic address: martinspinge@uel.br.
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MC
Martins-Pinge
D000818:Animals; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D001341:Autonomic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D017704:Baroreflex / Q000187:drug effects; D015306:Biogenic Monoamines / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D016627:Oxidopamine; D010302:Parkinson Disease, Secondary / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D013565:Sympatholytics
D000978:Antiparkinson Agents; D015306:Biogenic Monoamines; D013565:Sympatholytics; D007980:Levodopa; D016627:Oxidopamine; D004298:Dopamine
Arterial pressure; Head up tilt; Heart rate; Prolopa; Variability