Nigrostriatal dopamine system mediates baroreflex sensitivity in rats

Lu, Shiduo; H, Young; Lin, Mao‐Tsun

doi:10.1016/0304-3940(95)11489-j

Cited by 18 publications

(11 citation statements)

References 10 publications

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“…Unilateral injection of 6-hydroxydopamine into the nigrostriatal pathway is widely used to establish a hemi-PD model in rats (30). It was reported that the nigrostriatal dopamine pathway may mediate BRS through the efferent parasympathetic pathway in the medulla of rats (31). In this study, both 6-hydroxydopamine-and rotenone-treated rats exhibited a significant decrease in BRS and an increase in BPV, which indicated baroreflex dysfunction, without any change in BP, HP, or HPV.…”

Section: Discussionmentioning

confidence: 54%

Arterial Baroreflex Dysfunction Fails to Mimic Parkinson’s Disease in Rats

Shen

et al. 2008

J Pharmacol Sci

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Abstract. Patients with Parkinson's disease (PD) often have attenuated baroreflex function, which may occur before the onset of PD-associated movement disorders. The aim of the present study was to test whether impaired arterial baroreflex (ABR) function could contribute to the pathogenesis of PD. 6-Hydroxydopamine (8 μg in 4 μl) was microinjected into the left substantia nigra of rats to establish unilateral PD models, and bilateral PD models were established in rats by administration of rotenone by osmotic minipump for four weeks, at a dose of 2.5 mg ⋅ kg −1 ⋅ day −1 . An ABR dysfunction model was obtained by performing sinoaortic denervation (SAD). Hemodynamic variables were determined in conscious rats. PD-like symptoms and dopamine content in corpus striatum (CS) were also assessed. 6-Hydroxydopamine and rotenone treatment and SAD were associated with enhanced blood pressure variability (BPV) and blunted baroreflex sensitivity (BRS). Rotenone, but not SAD, significantly reduced dopamine content in the CS, induced catalepsy, and inhibited rearing and exploratory behavior. SAD before the administration of rotenone did not aggravate the rotenone-induced dopaminergic lesion. Our findings do not support the presumption that ABR dysfunction contributes to the pathogenesis of PD in rats.

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Section: Discussionmentioning

confidence: 54%

Arterial Baroreflex Dysfunction Fails to Mimic Parkinson’s Disease in Rats

Shen

et al. 2008

J Pharmacol Sci

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“…Although some authors have detected abnormal changes in the heart rate variability indicative of parasympathetic dysfunctions during the Valsalva maneuver in PD, it was difficult to determine the site of abnormality in its complicated reflex arc [9,12]. Furthermore, destruction of nigrostriatal dopaminergic system per se has been demonstrated to affect baroreflex sensitivity in rats [23]. Despite the difference in species, this result suggests caution in interpreting the results from the Valsalva maneuver in PD.…”

Section: Discussionmentioning

confidence: 87%

Cardiac parasympathetic dysfunction concurrent with cardiac sympathetic denervation in Parkinson's disease

Shibata¹,

Morita²,

Shimizu³

et al. 2009

Journal of the Neurological Sciences

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“…Our data showed that 6-OHDAlesioned rats presented increases in both the up and down gain of spontaneous baroreflex gain. Previous studies have shown that the nigrostriatal DA pathway mediates baroreflex sensitivity in rats (25). In addition, in the unilateral 6-OHDA model of PD, baroreflex gain is attenuated (42).…”

Section: Discussionmentioning

confidence: 90%

Dysautonomias in Parkinson's disease: cardiovascular changes and autonomic modulation in conscious rats after infusion of bilateral 6-OHDA in substantia nigra

Ariza

Sisdeli

Crestani

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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It is important to elucidate the mechanism of dysautonomias in patients with Parkinson's disease; therefore, this study aimed to investigate the cardiovascular and autonomic changes that occur in an animal model of Parkinsonism. Adult male Wistar rats were anesthetized before bilateral microinfusions of 6-hydroxydopamine (6-OHDA) into the substantia nigra. The sham group underwent the same surgical procedure but received vehicle. After 7 days, the mean arterial pressure (MAP) and heart rate (HR) were measured, and various drugs were injected into conscious rats through cannulas previously implanted in the femoral artery and vein. Spectral analyses of systolic arterial pressure (SAP) and pulse interval (PI) were conducted with the CardioSeries software as the spontaneous baroreflex gain and effectivity. The animals were subjected to ␣-, ␤-adrenergic, or muscarinic receptor antagonism. For confirmation of the lesion, the levels of dopamine in the striatum were quantified by high-performance liquid chromatography. Animals that underwent 6-OHDA microinfusion had lower MAP and HR compared with those in the sham group. Spectral analysis of SAP showed that 6-OHDA animals exhibited a decrease in the sympathetic component. The PI values did not differ between groups. After the administration of muscarinic and ␤-adrenergic antagonists, the cardiovascular measures did not differ between the groups. However, upon administration of the ␣-adrenergic antagonist, the 6-OHDA animals exhibited a lower decrease in the MAP. We report cardiovascular impairments in 6-OHDA animals, possibly due to decreased sympathetic activity. Determination of the origin of these changes (central or peripheral) requires further investigation. sympathetic; parasympathetic; prazosin; spectral analysis; dopamine; baroreflex PARKINSON'S DISEASE (PD) is characterized by a decrease in striatal dopamine (DA) levels due to the death of neurons in the substantia nigra pars compacta (SNpc). After an 80% decrease of DA levels in the striatum, the classic motor symptoms of PD appear (11,38). These include bradykinesia, rigidity, tremor, and postural instability (29). Although the motor signs of PD are well studied and recognized, symptoms of dysautonomia, despite being reported at all stages of PD, are rarely considered clinically even if they are the main complaint. Dysautonomia considerably impairs the quality of life in the early stages, and it can be debilitating with advancing disease (7,8).Cardiovascular involvement is very common in patients with PD (21, 24). Orthostatic hypotension (OH), postprandial hypotension, as well as cardiac arrhythmias, livedo reticularis, and leg edema are commonly reported (26,43). OH is the most reported symptom with a prevalence of up to 58% in patients with PD (18,24). However, despite all of the speculation, the pathophysiology of OH, as well as the severity of hemodynamic compromise, remains controversial. This has been associated with a central disorder that impacts the medulla, namely, the involvement of both the centra...

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Nigrostriatal dopamine system mediates baroreflex sensitivity in rats

Cited by 18 publications

References 10 publications

Arterial Baroreflex Dysfunction Fails to Mimic Parkinson’s Disease in Rats

Arterial Baroreflex Dysfunction Fails to Mimic Parkinson’s Disease in Rats

Cardiac parasympathetic dysfunction concurrent with cardiac sympathetic denervation in Parkinson's disease

Dysautonomias in Parkinson's disease: cardiovascular changes and autonomic modulation in conscious rats after infusion of bilateral 6-OHDA in substantia nigra

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