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Qingsong Lin, Guiling Zhao, Xi Fang, Xiaohong Peng, Huayuan Tang, Hong Wang, Ran Jing, Jie Liu, W Jonathan Lederer, Ju Chen, Kunfu Ouyang
Inositol 1, 4, 5-trisphosphate receptor-mediated (IP3R-mediated) calcium (Ca(2+)) release has been proposed to play an important role in regulating vascular smooth muscle cell (VSMC) contraction for decades. However, whether and how IP3R regulates blood pressure in vivo remains unclear. To address these questions, we have generated a smooth muscle-specific IP3R triple-knockout (smTKO) mouse model using a tamoxifen-inducible system. In this study, the role of IP3R-mediated Ca(2+) release in adult VSMCs on aortic vascular contractility and blood pressure was assessed following tamoxifen induction...
October 20, 2016: JCI Insight
Ulrike Herberg, Katharina Linden, Oliver Dewald, Eva Gatzweiler, Matthias Seehase, Georg Daniel Duerr, Jonas Dörner, Stephanie Kleppe, Dennis Ladage, Johannes Breuer
BACKGROUND: Pressure-volume loops (PVL) provide vital information regarding ventricular performance and pathophysiology in cardiac disease. Unfortunately, acquisition of PVL by conductance technology is not feasible in neonates and small children due to the available human catheter size and resulting invasiveness. The aim of the study was to validate the accuracy of PVL in small hearts using volume data obtained by real-time three-dimensional echocardiography (3DE) and simultaneously acquired pressure data...
2016: PloS One
Takeshi Kinoshita, Masashi Tawa, Tomoaki Suzuki, Yoshinari Aimi, Tohru Asai, Tomio Okamura
OBJECTIVES: The present study was designed to evaluate the association between chronic kidney disease and the endothelial function of internal thoracic artery (ITA) grafts in patients undergoing coronary bypass surgery. An isometric tension study was performed in ITA strips obtained during surgery. Concentration-response curves for acetylcholine (ACh) and sodium nitroprusside were constructed in ITA strips partially precontracted with phenylephrine under the inhibition of cyclooxygenase...
September 23, 2016: Journal of Thoracic and Cardiovascular Surgery
F Y Kwok, S Venugobal
BACKGROUND: Induction of anaesthesia with propofol is often associated with a significant decrease in arterial pressure, especially in the older population. The aim of this study is to determine the efficacy of phenylephrine in two different doses i.e. 100mcg and 200mcg, given during induction to counteract the anticipated hypotensive effect of propofol in older patients aged over 55 years. METHODS: Seventy-two ASA physical status I - II patients aged 55 years or older were randomly allocated to group 1 (received propofol mixed with normal saline), group 2 (propofol mixed with 100mcg of phenylephrine) or group 3 (propofol mixed with 200mcg of pheynylphrine)...
August 2016: Medical Journal of Malaysia
Luisa Iacovelli, Luisa Di Menna, Daniel Peterlik, Christina Stangl, Rosamaria Orlando, Gemma Molinaro, Antonio De Blasi, Valeria Bruno, Giuseppe Battaglia, Peter J Flor, Nicole Uschold-Schmidt, Ferdinando Nicoletti
We studied the interaction between mGlu7 and α1-adrenergic receptors in heterologous expression systems, brain slices, and living animals. L-2-Amino-4-phosphonobutanoate (L-AP4), and l-serine-O-phosphate (L-SOP), which activate group III mGlu receptors, restrained the stimulation of polyphosphoinositide (PI) hydrolysis induced by the α1-adrenergic receptor agonist, phenylephrine, in HEK 293 cells co-expressing α1-adrenergic and mGlu7 receptors. The inibitory action of L-AP4 was abrogated by (i) the mGlu7 receptor antagonist, XAP044; (ii) the C-terminal portion of type-2 G protein coupled receptor kinase; and (iii) the MAP kinase inhibitors, UO126 and PD98059...
October 18, 2016: Neuropharmacology
Jay S Naik, Jessica M Osmond, Benjimen R Walker, Nancy L Kanagy
Hydrogen sulfide (H2S) is a recently described gaseous vasodilator produced within the vasculature by the enzymes cystathionine γ-lyase and 3-mercaptopyruvate sulfurtansferase. Previous data demonstrate that endothelial cells (EC) are the source of endogenous H2S production and are required for H2S-induced dilation. However, the signal transduction pathway activated by H2S within EC has not been elucidated. TRPV4 and large conductance Ca(2+)-activated K channels (BK channels) are expressed in EC. H2S-induced dilation is inhibited by luminal administration of iberiotoxin and disruption of the endothelium...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Donal Melanaphy, Christpher D Johnson, Maxim Kustov, Connall Watson, Lyudmyla Borysova, Theodore Burdyga, Alexander V Zholos
Transient receptor potential melastatin 8 (TRPM8) is the principal cold and menthol receptor channel. Characterized primarily for its cold sensing role in sensory neurons, it is expressed and functional in several non-neuronal tissues, including vasculature. We previously demonstrated that menthol causes vasoconstriction and vasodilatation in isolated arteries, depending on vascular tone. Here we investigated calcium's role in responses mediated by TRPM8 ligands in rat tail artery myocytes using patch-clamp electrophysiology and ratiometric Ca(2+) recording...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Seung Kyum Kim, Joshua J Avila, Michael P Massett
Understanding the genetic influence on vascular reactivity is important for identifying genes underlying impaired vascular function. The purpose of this study was to characterize the genetic contribution to intrinsic vascular function and to identify loci associated with phenotypic variation in vascular reactivity in mice. Concentration response curves to phenylephrine (PE), potassium chloride (KCl), acetylcholine (ACh), and sodium nitroprusside (SNP) were generated in aortic rings from male mice (12-wk old) from 27 inbred mouse strains...
October 7, 2016: Physiological Genomics
Ipsita Mohanty, Sujit Suklabaidya, Subas Chandra Parija
OBJECTIVE: The objective of this study was to characterize the α1-adrenoceptor (α1-AR) subtypes and evaluate the effect of acidosis on α1-AR function and expression in goat superior mesenteric artery (GSMA). MATERIALS AND METHODS: GSMA rings were mounted in a thermostatically controlled (37.0°C ± 0.5°C) organ bath containing 20 ml of modified Krebs-Henseleit solution, maintained at pHo of 7.4, 6.8, 6.0, 5.5, 5.0, and 4.5. Noradrenaline (NA)- and phenylephrine (PE)-induced contractile response was elicited in the absence or presence of endothelium and prazosin at pHo of 7...
July 2016: Indian Journal of Pharmacology
Francisco J Rios, Katie Y Hood, A Karvey, Karla B Neves, Panagiota Anyfanti, Ryszard Nosalski, Livia L Camargo Ll, Augusto C Montezano, Rhian M Touyz
OBJECTIVE: TRPM7 is cation channel with intrinsic kinase activity important for cellular Mg homeostasis. We recently showed that TRPM7-kinase plays a role in aldosterone-mediated vascular effects and inflammation. Here we explored the putative role of TRPM7-kinase in cardiac fibrosis and vascular function in aldosterone-induced hypertension in mice. DESIGN AND METHOD: Wild-type (WT) or heterozygote TRPM7-kinase domain (TRPM7+/-) mice were treated with infused aldosterone (600 μg/Kg/day) and NaCl 1% in drinking water (aldo/salt) for 4 weeks...
September 2016: Journal of Hypertension
Michal Behuliak, Michal Bencze, Anna Vavrinova, Ivana Vaneckova, Josef Zicha
OBJECTIVE: Voltage-dependent calcium channels (VDCCs) play an important role in two major abnormalities observed in spontaneously hypertensive rats (SHR) - hyperactivity of sympathetic nervous system (SNS) and enhanced Ca influx to vascular smooth muscle cells (VSMC). α2δ subunit of VDCC, which promotes surface trafficking and modulates the biophysical properties of VDCC, was identified as a critical component of increased L-type VDCC calcium currents in arterial myocytes of SHR. On the other hand, N-type VDCCs control a neurotransmitter release in the peripheral sympathetic nervous system and play an important role in sympathetic hyperactivity in SHR...
September 2016: Journal of Hypertension
Shahbaz R Arain, Julie K Freed, Jutta Novalija, Paul S Pagel, Thomas J Ebert
OBJECTIVE: The mechanism of perioperative hypotension in patients taking an angiotensin-receptor blocker up to the time of surgery remains unclear. This study tested the hypothesis that short-term angiotensin-receptor blocker treatment attenuated the sympathetic and vascular responses to autonomic stimuli in volunteers undergoing anesthesia. DESIGN: Randomized, crossover, blinded, pilot design. SETTING: Zablocki Veterans Affairs Medical Center, Milwaukee, WI...
August 11, 2016: Journal of Cardiothoracic and Vascular Anesthesia
Li-Jie Wang, Wei-Dong Liu, Liang Zhang, Ke-Tao Ma, Lei Zhao, Wen-Yan Shi, Wen-Wen Zhang, Ying-Zi Wang, Li Li, Jun-Qiang Si
Niflumic acid (NFA) is a novel gap junction (GJ) inhibitor. The aim of the present study was to investigate the effect of NFA on GJ communication and the expression of connexin (Cx) in vascular smooth muscle cells (VSMCs) of mesenteric arterioles of spontaneously hypertensive rats (SHR). Whole‑cell patch clamp recording demonstrated that NFA at 1x10‑4 M significantly inhibited the inward current and its effect was reversible. The time for charging and discharging of cell membrane capacitance (Cinput) reduced from 9...
September 26, 2016: Molecular Medicine Reports
N H Sperna Weiland, D Breevoord, D A Jöbsis, E M F H de Beaumont, V Evers, B Preckel, M W Hollmann, S van Dieren, B A J M de Mol, R V Immink
Despite a rise in blood pressure, cerebral oxygenation decreases following phenylephrine administration, and we hypothesised that phenylephrine reduces cerebral oxygenation by activating cerebral α1 receptors. We studied patients on cardiopulmonary bypass during constant flow. Phenylephrine raised mean arterial pressure (α1 -mediated) from mean (SD) 69 (8) mmHg to 79 (8) mmHg; p = 0.001, and vasopressin raised mean arterial pressure (V1 mediated) from 69 (8) mmHg to 83 (6) mmHg; p = 0.001. Both drugs elicited a comparable decrease in cerebral oxygenation from 61 (7)% to 60 (7)%; p = 0...
October 17, 2016: Anaesthesia
M Hirschvogel, M Bassilious, L Jagschies, S M Wildhirt, M W Gee
A model for patient-specific cardiac mechanics simulation is introduced, incorporating a 3-dimensional finite element model of the ventricular part of the heart which is coupled to a reduced-order 0-dimensional closed-loop vascular system, heart valve and atrial chamber model.The ventricles are modeled by a nonlinear orthotropic passive material law. The electrical activation is mimicked by a prescribed parametrized active stress acting along a generic muscle fiber orientation. Our activation function is constructed such that the start of ventricular contraction and relaxation as well as the active stress curve's slope are parameterized...
October 15, 2016: International Journal for Numerical Methods in Biomedical Engineering
Tsontcho Ianchulev, Arturo Chayet, Malik Kahook, Mark Packer, Louis Pasquale, Robert N Weinreb
AIM: Eyedroppers deliver medication volumes exceeding conjunctival absorptive capacity, causing spillage and risking ocular/systemic complications. We evaluated piezoelectric microdosing. Results/methodology: Subjects (n = 102) received precision microdroplet delivery of phenylephrine (2.5%) and tropicamide (1.0%): 1 × 1.5 μl, 1 × 6 μl or 2 × 3 μl of each (randomized 1:1:1), into one eye. Contralateral eyes received eyedropper doses of both drugs. Outcomes were pupil dilation (0-60 min) and patient satisfaction...
October 13, 2016: Therapeutic Delivery
Christopher P Jackman, Aaron L Carlson, Nenad Bursac
Engineered cardiac tissues hold promise for cell therapy and drug development, but exhibit inadequate function and maturity. In this study, we sought to significantly improve the function and maturation of rat and human engineered cardiac tissues. We developed dynamic, free-floating culture conditions for engineering "cardiobundles", 3-dimensional cylindrical tissues made from neonatal rat cardiomyocytes or human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) embedded in fibrin-based hydrogel. Compared to static culture, 2-week dynamic culture of neonatal rat cardiobundles significantly increased expression of sarcomeric proteins, cardiomyocyte size (∼2...
December 2016: Biomaterials
Lourdes Dias, Mariana A P Rodrigues, Bruna R Inoue, Renata L Rodrigues, André L Rennó, Valéria B de Souza, Frank D Torres-Huaco, Norma C Sousa, Alessandra Stroka, Anibal R Melgarejo, Stephen Hyslop
In this work, we examined some mechanisms involved in the hypotension caused by Lachesis muta (South American bushmaster) venom in anesthetized rats. Venom (1.5 mg/kg, i.v.) caused immediate hypotension that was maximal after 5 min and gradually returned to baseline over 60 min. Pretreatment of rats with the non-selective nitric oxide synthase (NOS) inhibitor N(ω)-nitro-L-arginine methyl ester (L-NAME) did not attenuate the early phase of venom-induced hypotension, but abolished the recovery phase and resulted in rapid death; a similar effect was observed with the soluble guanylate cyclase (sGC) inhibitor ODQ...
October 5, 2016: Toxicon: Official Journal of the International Society on Toxinology
M C Vallejo, A F Attaallah, O M Elzamzamy, D T Cifarelli, A L Phelps, G R Hobbs, R E Shapiro, P Ranganathan
BACKGROUND: During spinal anesthesia for cesarean delivery phenylephrine is the vasopressor of choice but can cause bradycardia. Norepinephrine has both β- and α-adrenergic activity suitable for maintaining blood pressure with less bradycardia. We hypothesized that norepinephrine would be superior to phenylephrine, requiring fewer rescue bolus interventions to maintain blood pressure. METHODS: Eighty-five parturients having spinal anesthesia for elective cesarean delivery were randomized to Group P (phenylephrine 0...
August 28, 2016: International Journal of Obstetric Anesthesia
Madison B Schwartz, Jason A Ferreira, Patrick M Aaronson
BACKGROUND: The utilization of bolus-dose phenylephrine (PHE) has transitioned to the emergency department (ED) for the treatment of acutely hypotensive patients, despite a paucity of literature in this setting. METHODS: This was a single center retrospective chart review of the utilization of bolus-dosed PHE for acute hypotension in the ED at an academic non-forprofit hospital. The primary objective of this study is to report the frequency of patients that were initiated on a continuous vasopressor infusion (CVI) within 30 minutes after the first administration of bolus-dose PHE...
September 22, 2016: American Journal of Emergency Medicine
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