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https://www.readbyqxmd.com/read/28943248/the-medial-preoptic-area-modulates-autonomic-function-under-resting-and-stress-conditions
#1
Aline Fassini, América A Scopinho, Fernando H F Alves, Eduardo A T Fortaleza, Fernando M A Corrêa
The medial preoptic area (mPOA) participates in the temperature and cardiovascular control. The mPOA receives inputs from limbic structures and sends projections to hypothalamus and brainstem. Moreover, stress elicits pronounced neuronal activation in mPOA, suggesting its involvement in central neural pathway mediating stress responses. In the present study, we report the effect of acute mPOA neurotransmission inhibition using cobalt chloride (CoCl2-nonselective synapse blocker) on the mean arterial pressure (MAP), heart rate (HR), body and tail temperature (Tbody and Ttail, respectively), as well as on the HR component of baroreflex...
September 21, 2017: Neuroscience
https://www.readbyqxmd.com/read/28939650/muscle-sympathetic-nerve-responses-to-passive-and-active-one-legged-cycling-insight-into-the-contributions-of-central-command
#2
Connor J Doherty, Anthony V Incognito, Karambir Notay, Matthew J Burns, Joshua T Slysz, Jeremy D Seed, Massimo Nardone, Jamie F Burr, Philip J Millar
The contribution of central command to the peripheral vasoconstrictor response during exercise has been investigated using primarily handgrip exercise. The purpose of the present study was to compare muscle sympathetic nerve activity (MSNA) responses during passive (involuntary) and active (voluntary) zeroload cycling to gain insight into the effects of central command on sympathetic outflow during dynamic exercise. Hemodynamic measurements and contralateral leg MSNA (microneurography) were collected in eighteen young healthy participants at rest and during 2 minutes of passive and active zeroload one-legged cycling...
September 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28937240/baroreflex-sensitivity-in-premature-infants-relation-to-the-parameters-characterizing-intrauterine-and-postnatal-condition
#3
K Haskova, M Javorka, B Czippelova, M Zibolen, K Javorka
At present, there are insufficient information about baroreflex sensitivity (BRS) and factors that determine BRS in premature newborns. The objective of this study was to determine the relationship between BRS and the characteristics that reflecting the intrauterine development (gestational age and birth weight), as well as postnatal development (postconception age and the actual weight of the child at the time of measurement). We examined 57 premature infants, who were divided into groups according to gestational age and postconception age as well as birth weight, and weight at the time of measurement...
September 22, 2017: Physiological Research
https://www.readbyqxmd.com/read/28936180/mouse-anaphylactic-hypotension-is-characterized-by-initial-baroreflex-independent-renal-sympathoinhibition-followed-by-sustained-renal-sympathoexcitation
#4
Tao Zhang, Mamoru Tanida, Kunitoshi Uchida, Yoshiro Suzuki, Wei Yang, Yuhichi Kuda, Yasutaka Kurata, Makoto Tominaga, Toshishige Shibamoto
Aim: The hemodynamic response to mouse systemic anaphylaxis is characterized by an initial hypertension followed by sustained hypotension. However, the defense mechanisms of the sympathetic nervous system against this circulatory disturbance is not known. Here, we investigated the renal sympathetic nerve activity (RSNA) response to mouse systemic anaphylaxis, along with the roles of carotid sinus baroreceptor, vagal nerves and the transient receptor potential vanilloid type 1 channel (TRPV1). Methods: Male ovalbumin-sensitized C57BL/6N mice were used under pentobarbital anesthesia...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28919768/ictal-heart-rate-changes-and-the-effects-of-vagus-nerve-stimulation-for-patients-with-refractory-epilepsy
#5
Wei Chen, Fan-Gang Meng
Vagus nerve stimulation (VNS) shows long-term efficiency worldwide in most pharmacoresistant patients with epilepsy; however, there are still a small number of patients who are non-responders to VNS therapy. It has been shown that VNS treatment outcomes for drug-resistant epilepsy may be predicted by preoperative heart-rate variability measurements and that patients with epilepsy with ictal tachycardia (IT) during seizures have good responses to VNS. However, few studies have reported the efficacy of VNS in patients with epilepsy with ictal bradycardia (IB) or normal heart rate (HR), and none have explored the possible mechanisms of VNS efficacy based on different HR types...
2017: Neuropsychiatric Disease and Treatment
https://www.readbyqxmd.com/read/28912362/sympathetic-function-during-whole-body-cooling-is-altered-in-hypertensive-adults
#6
Jody L Greaney, W Larry Kenney, Lacy M Alexander
During moderate cold exposure, cardiovascular-related morbidity and mortality increase disproportionately in hypertensive adults (HTN); however, the mechanisms underlying this association are not well defined. We hypothesized that whole-body cold stress would evoke exaggerated increases in blood pressure (BP) and muscle sympathetic nerve activity (MSNA) in HTN compared to normotensive adults (NTN) and that sympathetic baroreflex function would be altered during cooling in HTN. MSNA (peroneal microneurography) and beat-to-beat BP (Finometer) were measured continuously in 10 NTN (6M/4W; age 53±3 yrs; resting BP 125±3/79±1 mmHg) and 13 HTN (7M/6W; age 58±2 yrs; resting BP 146±5/88±2 mmHg) during whole-body cooling-induced reductions in mean skin temperature (Tsk; water-perfused suit) from 34...
September 14, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28899913/central-chemoreflex-activation-induces-sympatho-excitation-without-altering-static-or-dynamic-baroreflex-function-in-normal-rats
#7
Keita Saku, Takeshi Tohyama, Masako Shinoda, Takuya Kishi, Kazuya Hosokawa, Takuya Nishikawa, Yasuhiro Oga, Takafumi Sakamoto, Hiroyuki Tsutsui, Tadayoshi Miyamoto, Kenji Sunagawa
Central chemoreflex activation induces sympatho-excitation. However, how central chemoreflex interacts with baroreflex function remains unknown. This study aimed to examine the impact of central chemoreflex on the dynamic as well as static baroreflex functions under open-loop conditions. In 15 anesthetized, vagotomized Sprague-Dawley rats, we isolated bilateral carotid sinuses and controlled intra-sinus pressure (CSP). We then recorded sympathetic nerve activity (SNA) at the celiac ganglia, and activated central chemoreflex by a gas mixture containing various concentrations of CO2 Under the baroreflex open-loop condition (CSP = 100 mmHg), central chemoreflex activation linearly increased SNA and arterial pressure (AP)...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28894435/neuroactive-steroids-receptor-interactions-and-responses
#8
REVIEW
Kald Beshir Tuem, Tesfay Mehari Atey
Neuroactive steroids (NASs) are naturally occurring steroids, which are synthesized centrally as de novo from cholesterol and are classified as pregnane, androstane, and sulfated neurosteroids (NSs). NASs modulate many processes via interacting with gamma-aminobutyric acid (GABA), N-methyl-d-aspartate, serotonin, voltage-gated calcium channels, voltage-dependent anion channels, α-adrenoreceptors, X-receptors of the liver, transient receptor potential channels, microtubule-associated protein 2, neurotrophin nerve growth factor, and σ1 receptors...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28891509/role-of-the-medullary-lateral-tegmental-field-in-sympathetic-control
#9
Michael George Zaki Ghali
The sympathetic nervous system maintains and regulates arterial pressure and tissue perfusion, via control of cardiac output and vasomotor tone. Sympatho-vascular-mediated increases in blood pressure are effected by arterioloconstriction, which causes an increase in afterload, and/or venoconstriction, which increases venous return, left ventricular preload, and consequently, the force of cardiac contraction via Frank-Starling mechanisms; withdrawal of sympathetic drive elicits reciprocal effects. Spinalization reduces mammalian arterial pressure to 40-50 mm Hg consequent to the elimination of descending medullary pre-sympathetic bulbospinal drive to preganglionic sympathetic fibers in the intermediolateral cell column of the spinal cord...
2017: Journal of Integrative Neuroscience
https://www.readbyqxmd.com/read/28888482/exercise-training-and-cardiac-autonomic-function-in-type-2-diabetes-mellitus-a-systematic-review
#10
REVIEW
Pooja Bhati, Shweta Shenoy, M Ejaz Hussain
Cardiac autonomic neuropathy (CAN) is a common complication of type 2 diabetes mellitus (T2DM). It has been found to independently predict all cause and cardiovascular disease (CVD) mortality. It remains unclear whether exercise training could improve autonomic control in T2DM patients. The purpose of this study was to systematically review the effects of exercise training on cardiac autonomic function in T2DM patients. Electronic databases (MEDLINE, CENTRAL, PEDro, Scopus and Web of science) were systematically searched to retrieve relevant evidence...
September 6, 2017: Diabetes & Metabolic Syndrome
https://www.readbyqxmd.com/read/28885986/estimation-of-baroreflex-sensitivity-by-the-bivariate-phase-rectified-signal-averaging-method-a-comparison-with-the-phenylephrine-method
#11
Roberto Maestri, Maria Teresa La Rovere, Grzegorz Raczak, Ludmiła Danilowicz-Szymanowicz, Gian Domenico Pinna
Background A novel technique to assess spontaneous baroreflex sensitivity (BRS) by bivariate phase-rectified signal averaging (PRSA-BRS) has been recently proposed and its independent prognostic power demonstrated. This method, however, has never been compared with the Phenyleprine test (Phe-BRS), commonly regarded as the reference method in clinical and research applications. Methods In 192 heart failure (HF) and 41 post-myocardial infarction (post-MI) patients we compared PRSA-BRS with Phe-BRS, assessing both association and agreement...
September 8, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28878683/association-between-diastolic-dysfunction-with-inflammation-and-oxidative-stress-in-females-ob-ob-mice
#12
Michelle Sartori, Filipe F Conti, Danielle da Silva Dias, Fernando Dos Santos, Jacqueline F Machi, Zaira Palomino, Dulce E Casarini, Bruno Rodrigues, Kátia De Angelis, Maria-Claudia Irigoyen
Objective: To evaluate autonomic and cardiovascular function, as well as inflammatory and oxidative stress markers in ob/ob female mice. Methods: Metabolic parameters, cardiac function, arterial pressure (AP), autonomic, hormonal, inflammatory, and oxidative stress markers were evaluated in 12-weeks female wild-type (WT group) and ob/ob mice (OB group). Results: OB animals showed increased body weight, blood glucose, and triglyceride levels, along with glucose intolerance, when compared to WT animals. Ejection fraction (EF) and AP were similar between groups; however, the OB group presented diastolic dysfunction, as well as an impairment on myocardial performance index...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28872781/armax-a-method-for-assessment-of-the-dynamic-response-of-the-arterial-baroreflex
#13
Morten T Lund, Max Salomonsson, Thomas E N Jonassen, Niels-Henrik Holstein-Rathlou
AIM: The baroreflex is a key mechanism in cardiovascular regulation and alterations in baroreceptor function are seen in many diseases, including heart failure, obesity and hypertension. We propose a new method for analyzing baroreceptor function from continuous blood pressure and heart rate in both health and disease. METHODS: 48-hour data series of blood pressure and heart rate were collected with telemetry. Sprague-Dawley rats on standard chow (n=11) served as controls, while rats on a high-fat, high-fructose diet (n=6) constituted the obese-hypertensive model...
September 5, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/28871339/recruitment-strategies-in-efferent-sympathetic-nerve-activity
#14
REVIEW
J Kevin Shoemaker
In 1968, the first reported microneurographic recordings of muscle sympathetic nerve activity (MSNA) in humans revealed the bursty behavior of efferent sympathetic nerve activity. The timing of bursts could be explained by baroreflex physiology, but the variability in size of each burst was left unexplained. On the basis of shorter latencies of larger bursts, Wallin's group [53] proposed the existence of variable supraspinal synaptic delays and/or options for recruitment of faster-conducting sympathetic neurons when bursts become stronger...
September 4, 2017: Clinical Autonomic Research: Official Journal of the Clinical Autonomic Research Society
https://www.readbyqxmd.com/read/28870716/endovascular-baroreflex-amplification-for-resistant-hypertension-a-safety-and-proof-of-principle-clinical-study
#15
Wilko Spiering, Bryan Williams, Jan Van der Heyden, Monique van Kleef, Rob Lo, Jorie Versmissen, Adriaan Moelker, Abraham Kroon, Hannes Reuter, Gary Ansel, Gregg W Stone, Mark Bates
BACKGROUND: Carotid baroreflex activation lowers blood pressure and might have potential application for the treatment of resistant hypertension. We did a proof-of-principle trial with a novel endovascular baroreceptor amplification device, MobiusHD (Vascular Dynamics, Mountain View, CA, USA), in patients with resistant hypertension. METHODS: CALM-FIM_EUR was a prospective, first-in-human, open-label study done at six European centres. Eligible patients were adults with resistant hypertension (office systolic blood pressure ≥160 mm Hg despite taking at least three antihypertensive agents, including a diuretic)...
September 1, 2017: Lancet
https://www.readbyqxmd.com/read/28862524/effect-of-anaesthetic-and-choice-of-neuromuscular-blocker-on-vagal-control-of-heart-rate-under-laboratory-animal-experimental-conditions
#16
Divya Sarma Kandukuri, Jacqueline K Phillips, Mark Tahmindjis, Cara M Hildreth
Neuromuscular-blocking agents are commonly used in laboratory animal research settings. Due to actions of cholinergic receptors at locations other than the motor end-plate, these agents have a strong propensity to modulate autonomic outflow and may therefore not be desirable in studies examining autonomic function. This study aimed to compare the effect of two non-depolarizing neuromuscular-blocking agents, pancuronium and cisatracurium, on blood pressure, heart rate and non-invasive indices of autonomic function (heart rate variability, systolic blood pressure variability and baroreflex sensitivity) under two different types of anaesthesia in Lewis rats...
January 1, 2017: Laboratory Animals
https://www.readbyqxmd.com/read/28862183/acute-effects-on-cardiovascular-oscillations-during-controlled-slow-yogic-breathing
#17
Om Lata Bhagat, Chhaya Kharya, Ashok Jaryal, Kishore Kumar Deepak
BACKGROUND & OBJECTIVES: Breathing exercises are believed to modulate the cardiovascular oscillations in the body. To assess the validity of the assumption and understand the underlying mechanism, the key autonomic regulatory parameters such as heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were recorded during controlled slow yogic breathing. Alternate nostril breathing (ANB) was selected as the yogic manoeuvre. METHODS: Twelve healthy volunteers (age 30±3...
April 2017: Indian Journal of Medical Research
https://www.readbyqxmd.com/read/28860965/resetting-of-the-baroreflex-control-of-sympathetic-vasomotor-activity-during-natural-behaviors-description-and-conceptual-model-of-central-mechanisms
#18
REVIEW
Roger A L Dampney
The baroreceptor reflex controls arterial pressure primarily via reflex changes in vascular resistance, rather than cardiac output. The vascular resistance in turn is dependent upon the activity of sympathetic vasomotor nerves innervating arterioles in different vascular beds. In this review, the major theme is that the baroreflex control of sympathetic vasomotor activity is not constant, but varies according to the behavioral state of the animal. In contrast to the view that was generally accepted up until the 1980s, I argue that the baroreflex control of sympathetic vasomotor activity is not inhibited or overridden during behaviors such as mental stress or exercise, but instead is reset under those conditions so that it continues to be highly effective in regulating sympathetic activity and arterial blood pressure at levels that are appropriate for the particular ongoing behavior...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28860964/inter-individual-relationships-between-sympathetic-arterial-baroreflex-function-and-cerebral-perfusion-control-in-healthy-males
#19
Trevor Witter, Yu-Chieh Tzeng, Terry O'Donnell, Jessica Kusel, Bridget Walker, Mary Berry, Chloe E Taylor
Maintenance of adequate cerebral perfusion during normal physiological challenges requires integration between cerebral blood flow (CBF) and systemic blood pressure control mechanisms. Previous studies have shown that cardiac baroreflex sensitivity (BRS) is inversely related to some measures of cerebral autoregulation. However, interactions between the sympathetic arterial baroreflex and cerebral perfusion control mechanisms have not been explored. To determine the nature and magnitude of these interactions we measured R-R interval, blood pressure, CBF velocity, and muscle sympathetic nerve activity (MSNA) in 11 healthy young males...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28860171/additive-effects-of-heating-and-exercise-on-baroreflex-control-of-heart-rate-in-healthy-males
#20
Tiago Peçanha, Claudia Lucia de Moraes Forjaz, David Andrew Low
This study assessed the additive effects of passive heating and exercise on cardiac baroreflex sensitivity (cBRS) and heart rate variability (HRV). Twelve healthy young men (25±1 yrs, 23.8±0.5 kg/m(2)) randomly underwent two experimental sessions: heat stress (HS; whole-body heat stress using a tube-lined suit to increase core temperature by ~1°C) and normothermia (NT). Each session was composed of a: pre-intervention rest (REST1); HS or NT interventions; post-intervention rest (REST2); and 14 min of cycling exercise [7 min at 40%HRreserve (EX1) and 7 min at 60%HRreserve (EX2)]...
August 31, 2017: Journal of Applied Physiology
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