Open-loop dynamic and static characteristics of the carotid sinus baroreflex in rats with chronic heart failure after myocardial infarction

Kawada, Toru; Li, Meihua; Kamiya, Atsunori; Shimizu, Shuji; Uemura, Kazunori; Yamamoto, Hiromi; Sugimachi, Masaru

doi:10.1007/s12576-010-0096-9

Cited by 44 publications

(75 citation statements)

References 45 publications

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“…A consistent observation in our laboratory, using a carotid bifurcation isolation procedure, is that an increase in baroreceptor region pressure up to 180 mmHg results in the SNA reduction to ϳ10% of the maximal SNA in WKY (14,30). In contrast, the same intervention only reduces SNA to ϳ40% in SD rats (12,13). Because C-fiber baroreceptors typically function at highpressure levels (24,25), the difference in the maximum SNA suppression suggests larger contribution of C-fiber baroreceptors to the SNA regulation in WKY compared with SD rats.…”

Section: Dynamic Characteristics Of A-and C-fiber Central Pathways Insupporting

confidence: 66%

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

Turner

Kawada

Shimizu

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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Section: Dynamic Characteristics Of A-and C-fiber Central Pathways Insupporting

confidence: 66%

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

Turner

Kawada

Shimizu

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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“…The static characteristics of the neural arc approximate an inverse sigmoidal curve, and those of the peripheral arc approximate a straight line. 18, 19 If we superimpose the neural and peripheral arcs on a pressure-SNA plane (a baroreflex equilibrium diagram), 11,12 the 2 arcs intersect. Under baroreflex closed-loop conditions, the system response or AP is settled at this intersection point, which is referred to as an operating point.…”

Section: Discussionmentioning

confidence: 99%

“…The increment and duration of each CSP step were 20 mmHg and 60 s, respectively. 18, 19 SNA was normalized in each animal such that the noise level of SNA recorded after the ganglionic blockade (hexamethonium bromide 60 mg/kg, i.v.) was zero, and the SNA value corresponding to the CSP level of 60 mmHg was 100%.…”

Section: Baroreflex Equilibrium Diagram In Shrmentioning

confidence: 99%

“…20,21 A postganglionic branch of the splanchnic sympathetic nerve was approached retroperitoneally to record SNA. 18, 19 The splanchnic nerve was used to represent sympathetic outflow because the splanchnic vascular bed contributes to approximately onethird of the change in the total vascular conductance in the AP regulation. 22 To estimate open-loop static characteristics of the carotid sinus baroreflex, carotid sinus pressure (CSP) was reduced to…”

Section: Protocol 1 (Acute Baroreflex Study N=8 For Each Group)mentioning

confidence: 99%

“…16,17, 19 In Protocol 1 ( Figures 2B and 2C), SNA was normalized in each animal so that the SNA value corresponding to the CSP level of 60 mmHg became 100%. This normalization hampers, for instance, the comparison of the maximum SNA between WKY and SHR.…”

Section: Conversion Of Sna In Shr Into the Units Of % In Wkymentioning

confidence: 99%

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Predominant Role of Neural Arc in Sympathetic Baroreflex Resetting of Spontaneously Hypertensive Rats

Sata

Kawada

Shimizu

et al. 2015

Circ J

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592SATA Y et al. Circulation JournalOfficial Journal of the Japanese Circulation Society http://www. j-circ.or.jp classified as a short-term blood pressure control system, 8 carotid baroreflex activation therapy has succeeded in reducing blood pressure in patients with resistant hypertension for more than 1 year, 9 suggesting a potential role of the arterial baroreflex in the long-term regulation of blood pressure. 10 Considering the multifactorial and complex nature of hypertension, further research is needed to understand how sympathetic nerve activity (SNA) and AP are determined in hypertension. The arterial baroreflex system constitutes a key link between the autonomic nervous system and the cardiovascular system. The reflex arc of baroreflex can be divided into 2 principal arcs: the neural arc from pressure input to SNA, and the peripheral arc from SNA to AP. 11,12 Under normal physiological conditions, because the arterial baroreflex operates as a closedloop feedback control system, it is difficult to separately quantify neural and peripheral arc characteristics.The behavior of a system might be described by dynamic and static characteristics. The dynamic characteristics determine he arterial baroreflex control of arterial pressure (AP) is known to reset to a higher input pressure range in hypertension. 1 To cope with the resetting, carotid baroreflex activation is proposed as a potential treatment of drugresistant hypertension. 2,3 Involvement of both neural and cardiovascular factors has been proposed in the pathophysiology of hypertension. Previous studies have demonstrated that sympathetic outflow from the central nervous system is increased in spontaneously hypertensive rats (SHR). 4,5 Peripheral factors such as cardiac hypertrophy and increased vascular resistance are also considered responsible for high AP in SHR. 6 Abnormality in vascular function is also reported in hypertensive patients. 7 Editorial p 510Device-based neuromodulation therapy has increasingly drawn scientific interest. While the arterial baroreflex has been Background: There is ongoing controversy over whether neural or peripheral factors are the predominant cause of hypertension. The closed-loop negative feedback operation of the arterial baroreflex hampers understanding of how arterial pressure (AP) is determined through the interaction between neural and peripheral factors.

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An Injectable Neural Stimulation Electrode Made from an In‐Body Curing Polymer/Metal Composite

Trevathan

Baumgart

Nicolai

et al. 2019

Adv Healthcare Materials

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Implanted neural stimulation and recording devices hold vast potential to treat a variety of neurological conditions, but the invasiveness, complexity, and cost of the implantation procedure greatly reduce access to an otherwise promising therapeutic approach. To address this need, a novel electrode that begins as an uncured, flowable prepolymer that can be injected around a neuroanatomical target to minimize surgical manipulation is developed. Referred to as the Injectrode, the electrode conforms to target structures forming an electrically conductive interface which is orders of magnitude less stiff than conventional neuromodulation electrodes. To validate the Injectrode, detailed electrochemical and microscopy characterization of its material properties is performed and the feasibility of using it to stimulate the nervous system electrically in rats and swine is validated. The silicone-metal-particle composite performs very similarly to pure wire of the same metal (silver) in all measures, including exhibiting a favorable cathodic charge storage capacity (CSC C ) and charge injection limits compared to the clinical LivaNova stimulation electrode and silver wire electrodes. By virtue of its simplicity, the Injectrode has the potential to be less invasive, more robust, and more cost-effective than traditional electrode designs, which could increase the adoption of neuromodulation therapies for existing and new indications.

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Open-loop dynamic and static characteristics of the carotid sinus baroreflex in rats with chronic heart failure after myocardial infarction

Cited by 44 publications

References 45 publications

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

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

Predominant Role of Neural Arc in Sympathetic Baroreflex Resetting of Spontaneously Hypertensive Rats

An Injectable Neural Stimulation Electrode Made from an In‐Body Curing Polymer/Metal Composite

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