Differences in the dynamic baroreflex characteristics of unmyelinated and myelinated central pathways are less evident in spontaneously hypertensive rats

Turner, Michael J.; Kawada, Toru; Shimizu, Shuji; Fukumitsu, Masafumi; Sugimachi, Masaru

doi:10.1152/ajpregu.00315.2015

Cited by 7 publications

(8 citation statements)

References 33 publications

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“…This result is in contrast to the hypothesis that the aortic baroreceptors lower BP predominantly by altering the HR . There must still be a strong mechanism to lower the BP via the vascular resistance, and ADN stimulation is also known to decrease sympathetic nerve activity in the splanchnic area . However, these findings were obtained under the scenario of a dissected vagal nerve in sequence to clonidine application.…”

Section: Discussioncontrasting

confidence: 61%

Influence of Clonidine on Antihypertensive Selective Afferent Vagal Nerve Stimulation in Rats

Gierthmuehlen

Aguirre

Cota

et al. 2016

Neuromodulation: Technology at the Neural Interface

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Section: Discussioncontrasting

confidence: 61%

Influence of Clonidine on Antihypertensive Selective Afferent Vagal Nerve Stimulation in Rats

Gierthmuehlen

Aguirre

Cota

et al. 2016

Neuromodulation: Technology at the Neural Interface

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“…2014a), further suggesting a difference in the baroreflex‐mediated sympathetic control between the two normotensive strains of rats (Turner et al. 2015b).…”

Section: Discussionmentioning

confidence: 99%

“…The sustained suppression of SNA at high CSP levels is mediated by unmyelinated C‐fibers in baroreceptor afferents (Turner et al. ,b). Aside from general sympathetic activation due to central mechanism (Liu and Zucker ; Leenen ), we speculate that systemic inflammation associated with chronic heart failure may damage C‐fibers relative to A‐fibers, impairing the baroreflex‐mediated SNA suppression at high CSP levels.…”

Section: Discussionmentioning

confidence: 99%

“…P-value was calculated by two-way repeated measures analysis of variance. One factor is DMI (two levels) and the other factor is CSP (five levels sympathetic control between the two normotensive strains of rats (Turner et al 2015b). This study extended our previous findings in that the positive correlation between SNA and plasma NE concentration was also observed in the MI group despite the large interindividual variance of plasma NE concentration (Fig.…”

Section: Relationship Between Sna and Plasma Ne Concentrationmentioning

confidence: 99%

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Acute arterial baroreflex‐mediated changes in plasma catecholamine concentrations in a chronic rat model of myocardial infarction

Kawada

Akiyama

et al. 2016

Physiological Reports

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While it may be predictable that plasma norepinephrine (NE) concentration changes with efferent sympathetic nerve activity (SNA) in response to baroreceptor pressure inputs, an exact relationship between SNA and plasma NE concentration remains to be quantified in heart failure. We examined acute baroreflex‐mediated changes in plasma NE and epinephrine (Epi) concentrations in normal control (NC) rats and rats with myocardial infarction (MI) (n = 6 each). Plasma NE concentration correlated linearly with SNA in the NC group (slope: 2.17 ± 0.26 pg mL−1 %−1, intercept: 20.0 ± 18.2 pg mL−1) and also in the MI group (slope: 19.20 ± 6.45 pg mL−1 %−1, intercept: −239.6 ± 200.0 pg mL−1). The slope was approximately nine times higher in the MI than in the NC group (P < 0.01). Plasma Epi concentration positively correlated with SNA in the NC group (slope: 1.65 ± 0.79 pg mL−1 %−1, intercept: 115.0 ± 69.5 pg mL−1) and also in the MI group (slope: 7.74 ± 2.20 pg mL−1 %−1, intercept: 24.7 ± 120.1 pg mL−1). The slope was approximately 4.5 times higher in the MI than in the NC group (P < 0.05). Intravenous administration of desipramine (1 mg kg−1) significantly increased plasma NE concentration but decreased plasma Epi concentration in both groups, suggesting that neuronal NE uptake had contributed to the reduction in plasma NE concentration. These results indicate that high levels of plasma catecholamine in MI rats were still under the influence of baroreflex‐mediated changes in SNA, and may provide additional rationale for applying baroreflex activation therapy in patients with chronic heart failure.

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“…While central arc may be a better antonym of peripheral arc , we prefer using neural arc because the neural arc includes the characteristics of the baroreceptor transduction. When we estimated the barore ex dynamic characteristics from aortic depressor nerve stimulation to efferent SNA, we used the term central arc instead of neural arc [7].…”

Section: General Preparationmentioning

confidence: 99%

Linear and Nonlinear Analysis of the Carotid Sinus Baroreflex Dynamic Characteristics

Kawada

Mukkamala

Sugimachi

2019

ABE

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The arterial barore ex system is an important negative feedback system that controls arterial pressure (AP) within a normal range during daily activities. We have analyzed this system in anesthetized animals. Several issues need to be considered: the presence of physiological and measurement noises that interfere with the system identi cation, the closed-loop nature of the arterial barore ex system, the existence of parallel feedback systems that may modify the system responses, and the presence of nonlinear responses. We opened the negative feedback loop by surgically isolating the carotid sinus baroreceptor regions from the systemic circulation. We eliminated the effects from parallel feedback systems by sectioning the aortic depressor and vagal nerves. We used a white noise approach to estimate the system characteristics under contamination of physiological and measurement noises. The arterial barore ex system may be divided into the neural and peripheral arc subsystems. The neural arc represents the relationship between pressure inputs and efferent sympathetic nerve activity (SNA), which may be regarded as a controller subsystem. The peripheral arc represents the relationship between SNA and AP, which may be regarded as a plant subsystem. The neural arc reveals derivative characteristics whereas the peripheral arc reveals low-pass characteristics. Numerical simulations based on the analytical results indicate that the neural arc compensates for the slow peripheral arc to optimize the arterial barore ex system in achieving both stability and quickness. Impairment of arterial barore ex function is associated with cardiovascular diseases, and arti cial activation of the arterial barore ex system could be a device-based treatment for cardiovascular diseases associated with sympathetic hyperactivity. To improve the efcacy of such device-based therapy, we may need to understand the interactions between stimulated and non-stimulated barore ex systems. Although static sigmoidal nonlinearity of the arterial barore ex with threshold and saturation phenomena is well documented, dynamic nonlinearities are less understood. Further efforts are warranted to fully understand arterial barore ex function and to apply the knowledge to the medical eld.

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Differences in the dynamic baroreflex characteristics of unmyelinated and myelinated central pathways are less evident in spontaneously hypertensive rats

Abstract: Turner MJ, Kawada T, Shimizu S, Fukumitsu M, Sugimachi M. Differences in the dynamic baroreflex characteristics of unmyelinated and myelinated central pathways are less evident in spontaneously hypertensive rats.

Cited by 7 publications

References 33 publications

Influence of Clonidine on Antihypertensive Selective Afferent Vagal Nerve Stimulation in Rats

Influence of Clonidine on Antihypertensive Selective Afferent Vagal Nerve Stimulation in Rats

Acute arterial baroreflex‐mediated changes in plasma catecholamine concentrations in a chronic rat model of myocardial infarction

Linear and Nonlinear Analysis of the Carotid Sinus Baroreflex Dynamic Characteristics

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