A5086834158- Heart Rate Variability and Autonomic Control
- Neuroscience of respiration and sleep
- Cardiovascular and exercise physiology
- Receptor Mechanisms and Signaling
- Cardiovascular, Neuropeptides, and Oxidative Stress Research
- Renin-Angiotensin System Studies
- Hormonal Regulation and Hypertension
- Neuropeptides and Animal Physiology
- Cardiac electrophysiology and arrhythmias
- Cardiovascular Function and Risk Factors
- Ion Channels and Receptors
- Neuroscience and Neuropharmacology Research
- Pharmacological Receptor Mechanisms and Effects
- Cardiovascular Effects of Exercise
- Biochemical effects in animals
- Nitric Oxide and Endothelin Effects
- Adipose Tissue and Metabolism
- Ion channel regulation and function
- Blood Pressure and Hypertension Studies
- Eicosanoids and Hypertension Pharmacology
- Non-Invasive Vital Sign Monitoring
- Public health and occupational medicine
- Renal and Vascular Pathologies
- Heart Failure Treatment and Management
- Blood properties and coagulation
University of Auckland
2020-2025
University of Illinois Chicago
2023
University of Nebraska Medical Center
2018-2019
University of Oxford
2010-2017
Sir Robert McAlpine (United Kingdom)
2017
University of North Carolina at Chapel Hill
1994
Institute of Directors
1967
Abstract Heart rate variability (HRV) is a crucial indicator of cardiovascular health. Low HRV correlated with disease severity and mortality in heart failure. increases decreases each breath normal physiology termed respiratory sinus arrhythmia (RSA). RSA highly evolutionarily conserved, most prominent the young athletic lost disease. Despite this, current pacemakers either pace metronomic fashion or sense activity node. If has been cannot restore it. We hypothesized that restoration...
The autonomic phenotype of congestive cardiac failure is characterised by high sympathetic drive and impaired vagal tone, which are independent predictors mortality. We hypothesize that bradycardia to peripheral stimulation following high-level due sympatho-vagal crosstalk the adrenergic co-transmitters galanin neuropeptide-Y (NPY). Moreover we acts similarly NPY reducing acetylcholine release via a receptor mediated, protein kinase-dependent pathway. Prolonged right stellate ganglion (10...
The phrase complete vagal withdrawal is often used when discussing autonomic control of the heart during exercise. However, more recent studies have challenged this assumption. We hypothesized that cardiac activity increases exercise and maintains function via transmitters other than acetylcholine.Chronic direct recordings nerve activity, output, coronary artery blood flow, rate were recorded in conscious adult sheep whole-body treadmill Cardiac innervation left branch was confirmed with...
Recent studies in prehypertensive spontaneously hypertensive rats (SHR) have shown larger calcium transients and reduced norepinephrine transporter (NET) activity cultured stellate neurons compared with Wistar-Kyoto (WKY) controls, although the functional significance of these results is unknown. We hypothesized that peripheral sympathetic responsiveness SHR at 4 wk age would be exaggerated WKY. In vivo arterial pressure (under 2% isoflurane) was similar SHRs (88 ± 2/50 3 mmHg, n = 18) WKYs...
Abstract In the present study, channelrhodopsin 2 (ChR2) was specifically introduced into murine cells expressing Phenylethanolamine n-methyltransferase (Pnmt ) gene, which encodes for enzyme responsible conversion of noradrenaline to adrenaline. The new model enabled identification a distinctive class Pnmt-expressing neuroendocrine and their descendants (i.e. Pnmt + cell derived cells) within heart. Here, we show that predominantly localized left side adult Remarkably, many in atrium...
Measurement of the affinity microtubules for anti-cancer drug taxol is problematic, because are not stable at very low concentrations required to detect dissociation.We have circumvented this problem by using GTP analogue GMP-CPP (guanylyl a,P-methylenediphosphonate), which renders sufficiently allow binding studies with nonsaturating taxol.A Kd value equal about 10 MI was estimated from effect concentration on dilution-induced disassembly rate and [SHltaxol.With GTPmicrotubules tubulin-GDP...
AimsB-type natriuretic peptide (BNP)-natriuretic receptor A (NPR-A) signalling inhibits cardiac sympathetic neurotransmission, although C-type (CNP) is the predominant neuropeptide of nervous system with expression in heart and vasculature.We hypothesized that CNP acts similarly to BNP, transgenic rats (TGRs) neuron-specific overexpression a dominant negative NPR-B would develop heightened drive.........
Hypertension is associated with enhanced cardiac sympathetic transmission, although the exact mechanisms underlying this are still unknown. We hypothesized that defective function of norepinephrine uptake transporter (NET) may contribute to phenotype spontaneously hypertensive rat, and occur before development hypertension itself. The dynamic kinetics NET were monitored temporally using a novel fluorescent assay in cultured postganglionic neurons from stellate ganglion, superior cervical...
Abstract Sympathetic transduction is the study of how impulses sympathetic nerve activity (SNA) affect end‐organ function. Recently, resting bursts muscle SNA (MSNA) has been investigated and shown to have a role in maintenance blood pressure through changes vascular tone humans. In present study, we investigate whether directly recorded cardiac (CSNA) regulates heart rate (HR), coronary flow (CoBF), conductance (CVC), output (CO) mean arterial pressure. Instrumentation was undertaken record...
The erythrocyte sedimentation rate (ESR) is well established as a clinical test in diseased patients (Brit. med. J., 1960; Gibson, 1960). However, little seems to have been published concerning its value routine screening test. Borchgrevink, Heisto, and Reimers Reksten (1965) found 41 (2 per cent.) of 2,205 Norwegian male blood donors with an ESR over 20 mm./hr; nineteen these showed persist ent elevation. has not usually included programmes (Jungner, 1966; Collen, 1966), but we it great...
Hypertension is associated with increased sympathetic activity. A component of this sympathoexcitation may be driven by signaling from sensory endings the heart to autonomic control areas in brain. This pathway mediates so-called cardiac afferent reflex, which also activated coronary ischemia or other nociceptive stimuli heart. The reflex has been shown enhanced failure state and renal hypertension. However, little known about its role development progression hypertension phenotype involved....
The sensory innervation of the lung is well known to be innervated by nerve fibers both vagal and sympathetic origin. Although afferent has been characterized, less about physiological effects mediated spinal fibers. We hypothesized that activation would result in an excitatory pressor reflex, similar previously characterized heart. In this study, we evaluated changes renal activity (RSNA) hemodynamics response TRPV1-sensitive pulmonary agonist application visceral pleura administration into...
Background and purpose: To validate a fluorescence approach for monitoring norepinephrine transporter (NET) transport rate in mature sympathetic terminals, to determine how prejunctional muscarinic receptors affect NET rate. Experimental approach: Confocal imaging of fluorescent substrate [neurotransmitter uptake assay (NTUA)] as it accumulates the nerve terminals mouse isolated vas deferens. Fluorescence recovery after photobleaching (FRAP), enhanced green protein (EGFP)‐transgenic mice...
Activation of the carotid body (CB) using intracarotid potassium cyanide (KCN) injection increases coronary blood flow (CoBF). This increase in CoBF is considered to be mediated by co-activation both sympathetic and parasympathetic nerves heart. However, whether cardiac nerve activity (cardiac SNA) actually during CB activation has not been determined previously. We hypothesized that would directly recorded SNA, which cause vasodilatation. Experiments were conducted conscious sheep implanted...
Reduced cardiomyocyte excitation-contraction coupling and downregulation of the SERCA2a (sarcoendoplasmic reticulum calcium ATPase 2a) is associated with heart failure. This has led to viral transgene upregulation in cardiomyocytes as a treatment. We hypothesized that gene therapy expressed under similar promiscuous cytomegalovirus promoter could also affect cardiac sympathetic neural axis promote sympathoexcitation. Stellate neurons were isolated from 90 120 g male, Sprague-Dawley, Wistar...
Peripheral arterial chemoreceptors monitor the chemical composition of blood and include both carotid aortic bodies (ABs). While role has been extensively studied, physiological ABs remains relatively under-studied, its in hypertension is unexplored. We hypothesized that activation would increase coronary flow normotensive state this be mediated by parasympathetic nerves to heart. In addition, we determined whether response stimulation was altered an ovine model renovascular...
Carotid bodies (CBs) are peripheral chemoreceptors, which primary sensors of systemic hypoxia and their activation produces respiratory, autonomic, cardiovascular adjustments critical for body homeostasis. We have previously shown that carotid chemoreceptor stimulation increases directly recorded cardiac sympathetic nerve activity (cardiac SNA) coronary blood flow (CoBF) in conscious normal sheep. Previous studies chemoreflex sensitivity is augmented heart failure (HF). hypothesized would...
The spontaneously hypertensive rat (SHR) has increased peripheral cardiac sympathetic activity compared to Wistar Kyoto (WKY) controls. However, it is not clear whether this precedes the development of hypertension. We therefore responsiveness in SHR WKY at 4 weeks age. Ventricular weight/body weight ratios and mean arterial pressure measured via left carotid artery demonstrated that SHRs (n=8) were without ventricular hypertrophy normotensive age WKYs (n=7). In isolated cultured neurons...