Heart rate and arterial pressure variability in the experimental renovascular hypertension model in rats

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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“…MAP and HR were monitored until the drug effects were evaluated. The drug concentrations were chosen based on previous studies (14,20,36).…”

Section: Methodsmentioning

confidence: 99%

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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“…A módszer lehetővé teszi az egyes neurohumoralis rendszerek relatív részvételének megismerését, részvételi arányát a vérnyomás szabályo-zásában. A myogen vascularis funkció, a RAS és a NOhatás az igen alacsony frekvenciasávban [9], a vascularis tónus szimpatikus modulációja és a NO pedig az alacsony frekvenciasávban befolyásolja a BPV-t [10]. Gyakran használják a normalizált LF (LF/HF arány) indexet, mint a szimpatikus vascularis aktivitás jelzőjét a különbö-ző tanulmányokban [11].…”

Section: Ultrarövid Időtartamú Vérnyomás-variabilitásunclassified

Measurement of blood pressure variability and the clinical value

Kékes

Kiss

2014

Orvosi Hetilap

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A szerzők összefoglalják és elemzik a vérnyomás-variabilitásról szóló irodalmi adatokat. Bemutatják a vérnyomás-variabilitás mérési típusait, azok klinikai értékét, összefüggésüket a szervi károsodásokkal és a cardiovascularis esemé-nyek megjelenésének kockázatával. Jellemzik a prognosztikai értékre vonatkozó adatokat és áttekintik a különböző antihipertenzív szereknek a vérnyomás-variabilitásra kifejtett hatásait. Véleményük szerint ma már bizonyítottnak tekinthető, hogy a hypertonia kezelése során a vérnyomáscélérték elérése mellett törekedni kell a vérnyomás-variabilitás csökkentésére, a vérnyomás-fl uktuáció befolyásolására, mert ez jelenti az egyik legnagyobb veszélyt a hypertoniás egyén számára. Beszámolnak a hazai tapasztalatokról is. Reményteljesnek tartják, hogy a nemzetközi irányelvekben a vérnyomás-variabilitás mérése teret nyert. Orv. Hetil., 2014, 155(42), 1661-1672. Kulcsszavak: vérnyomás-variabilitás, vérnyomás-fl uktuáció, vérnyomás-variabilitás és szervi károsodások, vérnyo-más-variabilitás és hypertoniaprognózis, antihipertenzív gyógyszerhatás Measurement of blood pressure variability and the clinical valueAuthors have collected and analyzed literature data on blood pressure variability. They present the methods of blood pressure variability measurement, clinical value and relationships with target organ damages and risk of presence of cardiovascular events. They collect data about the prognostic value of blood pressure variability and the effects of different antihypertensive drugs on blood pressure variability. They underline that in addition to reduction of blood pressure to target value, it is essential to infl uence blood pressure fl uctuation and decrease blood pressure variability, because blood pressure fl uctuation presents a major threat for the hypertensive subjects. Data from national studies are also presented. They welcome that measurement of blood pressure variability has been included in international guidelines.Keywords: blood pressure variability, blood pressure fl uctuation, blood pressure variability and target organ damage, blood pressure variability and prognosis, effects of antihypertensive drugs Rövidítések ABPM = 24 órás vérnyomás-monitorozás; ACE = angiotenzinkonvertáló enzim; ARV = átlagos reális variabilitás; BP = vér-nyomás; BPV = vérnyomás-variabilitás; CAA = kalciumantagonista; CV = cardiovascularis; DBP = diasztolés vérnyomás; DBPV= diasztolés vérnyomás variabilitása; DM2T = 2-es típu-sú diabetes mellitus; ESC = European Society of Cardiology; ESH = European Society of Hypertension; GFR = glomerulusfi ltrációs ráta; HBPM = otthoni vérnyomásmérés; IMT = carotis intima-media vastagság; LF/HF = alacsony és magas frekvenciatartomány aránya (spectrumelemezés); LVH = balkamra-hipertrófi a; LVM = bal kamrai izommassza; NO = nitrogén-monoxid; OBPM = rendelői vérnyomásmérés; PTCA = percutan transluminalis koszorúér-tágítás; RAS = reninangio tenzin rendszer; SBP = szisztolés vérnyomás; SBPV = szisztolés vérnyomás variabilitás; SD = standard deviáció; SI = smoothness index;...

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“…In this context, while myogenic vascular function, renin angiotensin system, and endothelium-derived NO affect BPV at VLF [8,11], LF variability is modulated by sympathetic modulation of vascular tone and endothelial-derived NO in rats [11]. In addition, normalized LF (LF/HF ratio) has been validated as a marker of sympathetic vascular activity in preclinical and clinical studies [9,10]. Variability in the HF domain is mainly influenced by changes in cardiac output [12].…”

Section: Ultra-short-term Blood Pressure Variabilitymentioning

confidence: 99%

“…Different mechanisms can contribute in the increase of beatto-beat BPV, including enhanced central sympathetic drive, reduced arterial or cardiopulmonary baroreflex, humoral and rheological factors, behavioral and emotional mechanisms, and changes in ventilation [13]. Beat-to-beat BPV has been used for the study of the mechanism of action of antihypertensive drugs and the diagnosis and treatment of patients with cardiovascular diseases [8,9,11]. For instance, in our laboratory, we have shown that carvedilol induced a greater hypotensive response in spontaneously hypertensive rats in comparison with normotensive control animals [14].…”

Section: Ultra-short-term Blood Pressure Variabilitymentioning

confidence: 99%

Blood Pressure Variability: Prognostic Value and Therapeutic Implications

Höcht

2013

ISRN Hypertension

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Blood pressure variability (BPV) is considered nowadays a novel risk factor for cardiovascular disease. Early findings in sinoaortic denervated rats have clearly shown that enhanced fluctuation of blood pressure induced left ventricular hypertrophy, vascular stiffness, and renal lesion. A large number of clinical trials confirm that short-term and long-term blood pressure variability independently contributes to target organ damage, cardiovascular events, and mortality not only in hypertensive patients but also in subjects with diabetes mellitus and chronic kidney disease. Therefore, amelioration of BPV has been suggested as an additional target of the treatment of cardiovascular diseases. Preliminary evidence obtained from meta-analysis and controlled clinical trials has shown that antihypertensive classes differ in their ability to control excessive BP fluctuations with an impact in the prevention of cardiovascular events. Calcium channel blockers seem to be more effective than other blood pressure lowering drugs for the reduction of short-term and long-term BPV. In order to increase actual knowledge regarding the prognostic value and therapeutic significance of BPV in cardiovascular disease, there is a need for additional clinical studies specifically designed for the study of the relevance of short-term and long-term BPV control by antihypertensive drugs.

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Heart rate and arterial pressure variability in the experimental renovascular hypertension model in rats

Cited by 49 publications

References 36 publications

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

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

Measurement of blood pressure variability and the clinical value

Blood Pressure Variability: Prognostic Value and Therapeutic Implications

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