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Lebogang P Mokotedi, Frederic S Michel, Angela J Woodiwiss, Gavin R Norton, Aletta Me Millen
Sodium (Na)-intake increases vascular reactivity. Whether low potassium (K)-intake affects vascular reactivity associated blood pressure (BP) changes is uncertain. This study aimed to determine whether Na-induced increases in BP and vascular reactivity are altered by low K-intake. Male Sprague-Dawley rats were assigned to three dietary groups for six weeks: a standard Na-K diet (Control, n=12), a high Na-normal K diet (HS-NormK, n=12) and a high Na-low K diet (HS-LowK, n=12). BP was measured at baseline and after the dietary intervention...
March 12, 2018: Journal of Cardiovascular Pharmacology
Chu Shan Tan, Mun Fei Yam
Previous studies have demonstrated that 3'-hydroxy-5,6,7,4'-tetramethoxyflavone (TMF) content in Orthosiphon stamineus fractions correlate with its vasorelaxation activity. Even with the availability of previous studies, there is still very little information on the vasorelaxation effect of TMF, and few scientific studies have been carried out. Therefore, the present study was designed to investigate the vasorelaxation activity and mechanism of action of the TMF. The vasorelaxation activity and the underlying mechanisms of TMF were evaluated on thoracic aortic rings isolated from Sprague Dawley rats...
March 19, 2018: Naunyn-Schmiedeberg's Archives of Pharmacology
Sini M Kinnunen, Marja Tölli, Mika J Välimäki, Erhe Gao, Zoltan Szabo, Jaana Rysä, Mónica P A Ferreira, Pauli Ohukainen, Raisa Serpi, Alexandra Correia, Ermei Mäkilä, Jarno Salonen, Jouni Hirvonen, Hélder A Santos, Heikki Ruskoaho
Transcription factors are fundamental regulators of gene transcription, and many diseases, such as heart diseases, are associated with deregulation of transcriptional networks. In the adult heart, zinc-finger transcription factor GATA4 is a critical regulator of cardiac repair and remodelling. Previous studies also suggest that NKX2-5 plays function role as a cofactor of GATA4. We have recently reported the identification of small molecules that either inhibit or enhance the GATA4-NKX2-5 transcriptional synergy...
March 15, 2018: Scientific Reports
P A Stapleton, C R McBride, J Yi, A B Abukabda, T R Nurkiewicz
Preconceptive health encompasses male and female reproductive capability. In females, this takes into account each of the stages of the estrous cycle. Microvascular reactivity varies throughout the estrous cycle in response to hormonal changes and in preparation for pregnancy. Microvascular alterations in response to engineered nanomaterial (ENM) exposure have been described within 24-hours of inhalation; however, the impact upon the uterine vasculature at differing estrous stages and at late-stage pregnancy is unclear...
March 12, 2018: Reproductive Toxicology
Daniela Sorriento, Gaetano Santulli, Michele Ciccarelli, Angela Serena Maione, Maddalena Illario, Bruno Trimarco, Guido Iaccarino
We have recently demonstrated that the amino-terminal domain of G protein coupled receptor kinase (GRK) type 5, (GRK5-NT) inhibits NFκB activity in cardiac cells leading to a significant amelioration of LVH. Since GRK5-NT is known to bind calmodulin, this study aimed to evaluate the functional role of GRK5-NT in the regulation of calcium-calmodulin-dependent transcription factors. We found that the overexpression of GRK5-NT in cardiomyoblasts significantly reduced the activation and the nuclear translocation of NFAT and its cofactor GATA-4 in response to phenylephrine (PE)...
March 15, 2018: International Journal of Molecular Sciences
Shunsuke Shiina, Ayaka Kanemura, Chihiro Suzuki, Fumiko Yamaki, Keisuke Obara, Daisuke Chino, Yoshio Tanaka
Object We identified the β-adrenoceptor (β-AR) subtypes responsible for the relaxant responses to adrenaline (AD) and noradrenaline (NA) in the rat thoracic aorta and examined the role of cAMP which is involved in these relaxant responses. Methods The effects of β-AR antagonists or the adenylyl cyclase inhibitor SQ 22,536 on AD- and NA-induced relaxant responses in phenylephrine-induced contraction and increases in cAMP levels were examined in isolated, endothelium-denuded rat thoracic aorta segments. Results AD-induced relaxation was completely suppressed by propranolol (10-7  M) or by ICI-118,551 (10-8  M) plus atenolol (10-6 M), and was also very strongly inhibited by ICI-118,551 (10-8  M) alone...
2018: Journal of Smooth Muscle Research, Nihon Heikatsukin Gakkai Kikanshi
Vivek Krishna Pulakazhi Venu, Mahmoud Saifeddine, Koichiro Mihara, Mahmoud El-Daly, Darrell Belke, Jonathan L E Dean, Edward R O'Brien, Simon A Hirota, Morley D Hollenberg
BACKGROUND AND PURPOSE: Previously, we demonstrated that exogenous Heat Shock Protein 27 (HSP27/gene, HSPB1) treatment of human endothelial progenitor cells (EPCs) increases the synthesis and secretion of VEGF, improves EPC-migration/re-endothelialization and decreases neo-intima formation, suggesting a role for HSPB1 in regulating EPC function. We hypothesized that HSPB1 could also affect mature endothelial cells (ECs) to alter EC-mediated vasoreactivity in vivo. Our work focused on eNOS/NO-dependent relaxation caused by acetylcholine and the coagulation pathway-activated receptor, proteinase-activated receptor-2 (PAR2)...
March 12, 2018: British Journal of Pharmacology
Iris Lim, Russ Chess-Williams, Donna Sellers
This study investigated the role of calcium sensitisation in the regulation of ureteral contractility with ageing. Isolated ureteral strips from young (6-month old) and older (3-year old) pigs were mounted in Krebs bicarbonate solution and contractility induced by the α1-adrenoceptor agonist phenylephrine (30 and 300 μM) and 5-HT (10 and 100 μM), recorded in the absence and presence of the rho-kinase inhibitors Y-27632 (10 μM) and fasudil (30 μM). Ureteral strips developed bursts of contractile activity which was measured as area under the curve (AUC) and frequency...
March 9, 2018: Mechanisms of Ageing and Development
Lucía Isidoro, Mercedes Ferrer, Mercedes Perusquía
BACKGROUND: Testosterone, 5α- and 5β-dihydrotestosterone (-DHT) induce an acute in vitro vasorelaxation and in vivo vasodepressor, hypotensive and antihypertensive responses. Our aim was to study whether androgen-induced blood pressure (BP) reduction is involved with a blockade of Ca2+ influx through L-type voltage-operated calcium channels (L-VOCCs) and/or the signaling pathways of α1 -adrenoceptors to induce vasoconstriction, which are one of the major mechanisms of BP maintenance...
March 12, 2018: Endocrine Research
M Mohta, S Duggal, G T Chilkoti
Treatment of post-spinal hypotension during caesarean section assumes special concern in pre-eclamptic patients due to a compromised fetoplacental circulation and increased risk of placental hypoperfusion. Phenylephrine and ephedrine are the most commonly used vasopressors, although the best choice is still not clear. We studied 80 pre-eclamptic women with a singleton pregnancy who underwent caesarean section with spinal anaesthesia, and who developed hypotension defined as a decrease in systolic arterial pressure ≥ 20% from baseline or absolute value < 100 mmHg...
March 9, 2018: Anaesthesia
Naotaka Kishimoto, Munenori Kato, Yasunori Nakanishi, Akari Hasegawa, Yoshihiro Momota
Variant angina is caused by coronary artery spasm (CAS) with ST-segment elevation. We herein report a case of recurrent CAS during 2 operations in the same patient. An 80-year-old woman was scheduled to undergo tracheostomy, submandibular dissection, left partial maxillectomy, and coronoidectomy. We administered ephedrine and phenylephrine to manage hypotension during general anesthesia. Immediately after the administration of these drugs, the ST segment elevated. We decided to cease the operation and transport the patient to the department of cardiology...
2018: Anesthesia Progress
Deyamira Matuz-Mares, Alain Hernández-Vázquez, Héctor Riveros-Rosas, Raquel Guinzberg, Tania Quesada-López, Alfonso Cárabez-Trejo, Ofelia Mora, Enrique Piña
The physiological regulation of hepatic glutathione efflux by catecholamines is poorly understood. The purpose of this work was to review the role of adrenergic receptors (AR) on total glutathione (GT ) efflux in rat liver. Two models were used: isolated hepatocytes and perfused livers. In hepatocytes 10 μM adrenaline (Adr), but not isoproterenol (Iso) a β-AR agonist, or phenylephrine (Phe) an α1 -AR agonist, (in a Krebs-Henseleit Buffer (KHB) enriched with Ca2+ and some aminoacids) increased in 13% GT efflux...
February 26, 2018: Archives of Biochemistry and Biophysics
M Florencia Iulita, Diane Vallerand, Mélissa Beauvillier, Nathalie Haupert, Corinne A Ulysse, Audrey Gagné, Nathalie Vernoux, Sonia Duchemin, Michaël Boily, Marie-Ève Tremblay, Hélène Girouard
BACKGROUND: Angiotensin II (Ang II), a peptide hormone involved in the development of hypertension, causes systemic and cerebral inflammation, affecting brain regions important for blood pressure control. The cause-and-effect relationship between hypertension and inflammation is two-way, but the role of blood pressure in the induction of cerebral inflammation is less clear. The vulnerability of specific brain regions, particularly those important for memory, is also of interest. METHODS: We used molecular biology approaches, immunohistochemistry, and electron microscopy to examine the interdependence between the hypertensive and pro-inflammatory effects of Ang II...
February 28, 2018: Journal of Neuroinflammation
Jacqueline K Limberg, Elizabeth P Ott, Walter W Holbein, Sarah Elizabeth Baker, Timothy B Curry, Wayne T Nicholson, Michael J Joyner, J Kevin Shoemaker
To study how changes in baroreceptor afferent activity affect patterns of sympathetic neural activation, we manipulated arterial blood pressure using intravenous nitroprusside (NTP) and phenylephrine (PE) and measured action potential (AP) patterns with wavelet-based methodology. We hypothesized: 1) Baroreflex unloading (NTP) would increase firing of low-threshold axons and recruitment of latent axons, and 2) Baroreflex loading (PE) would decrease firing of low-threshold axons. Heart rate (HR, ECG), arterial blood pressure (BP, brachial catheter), and muscle sympathetic nerve activity (MSNA, microneurography of the peroneal nerve) were measured at baseline and during steady-state systemic, intravenous NTP (0...
February 28, 2018: Journal of Neurophysiology
Bailin Liu, Yanping Liu, Ruixiu Shi, Xueqin Feng, Xiang Li, Wenna Zhang, Jue Wu, Na Li, Xiuwen Zhou, Miao Sun, Zhice Xu
BACKGROUND/AIMS: Chronic hypoxia in utero could impair vascular functions in the offspring, underlying mechanisms are unclear. This study investigated functional alteration in large-conductance Ca2+-activated K+ (BK) channels in offspring mesenteric arteries following prenatal hypoxia. METHODS: Pregnant rats were exposed to normoxic control (21% O2, Con) or hypoxic (10.5% O2, Hy) conditions from gestational day 5 to 21, their 7-month-old adult male offspring were tested for blood pressure, vascular BK channel functions and expression using patch clamp and wire myograh technique, western blotting, and qRT-PCR...
February 21, 2018: Cellular Physiology and Biochemistry
O K Uche, J O Ofeimun
The mechanism of kolaviron-induced vascular smooth muscles (VSMs) responses has not been fullycharacterised. The present study investigated the effect and mode of action of kolaviron a biflavanoid-complex and majorcomponent of Garcinia Kola-fraction on differential contractile responses to agonists-[phenylephrine (PHE) and histamine(HIST)] on VSMs of rabbit isolated aortic rings in K+-free physiological salt solution (KFPSS). Cumulative concentrationresponses to PHE and HIST were examined on 2 mm ring segments of the thoracic aortae which were suspended in 20 mlorgan baths containing physiological salt solution (PSS) for measurement of isometric contractions, at 370C and pH 7...
December 30, 2017: Nigerian Journal of Physiological Sciences: Official Publication of the Physiological Society of Nigeria
Kjirsten Swenson, Shannon Rankin, Leticia Daconti, Tomas Villarreal, Jens Langsjoen, Darren Braude
INTRODUCTION: Bolus-dose phenylephrine (BDPE) is routinely used to treat hypotension in the operating room. BDPE's fast onset of action and ability to be administered peripherally have prompted calls for its use in the Emergency Department (ED). There are few published data on the safety of BDPE use in the ED. Primary concerns include BDPE's potential to cause dangerous hypertension or reflex bradycardia. We hypothesize that BDPE is a safe short-term vasopressor choice for hypotensive ED patients...
February 19, 2018: American Journal of Emergency Medicine
Alexandre F Cunha, Igor S A Felippe, Nilson C Ferreira-Junior, Leonardo B M Resstel, Daniela A M Guimarães, Vanessa Beijamini, Julian F R Paton, Karla N Sampaio
Although it is well-established that severe poisoning by organophosphorus (OP) compounds strongly affects the cardiorespiratory system, the effects of sub-lethal exposure to these compounds on the neural control of cardiovascular function are poorly explored. The aim of this study was to evaluate the effects of acute sub-lethal exposure to chlorpyrifos (CPF), a commonly used OP insecticide, on three basic reflex mechanisms involved in blood pressure regulation, the peripheral chemoreflex, the baroreflex and the Bezold-Jarisch reflex...
February 19, 2018: Toxicology
Mark Johnson, Elaine Murphy, Amr Raheem, David Ralph
We report on the 1st case of ischemic priapism secondary to poorly controlled homocystinuria. Homocystinuria is a rare, autosomal recessive, inherited disorder of metabolism that is caused by a deficiency of cystathionine synthase, leading to marked hyperhomocysteinemia. Arterial and/or venous thromboemboli are a major cause of mortality and morbidity in patients with homocystinuria. Untreated patients have a 50% chance of having a vascular event by 30 years of age. Increased homocysteine levels have been reported to upregulate prothrombotic factors and downregulate antithrombotic factors; in particular, increased homocystinuria has been found to downregulate nitric oxide (NO)...
February 17, 2018: Sexual Medicine
Hirotake Ishida, Shin-Ya Saito, Eita Hishinuma, Tomoaki Kitayama, Tomohisa Ishikawa
Our previous studies have shown that α1 -adrenoceptors, in addition to α2 -adrenoceptors, are involved in enhanced contraction of cutaneous blood vessels during cooling. The present study aimed to elucidate the mechanism underlying it. In tail and iliac arteries isolated from rats, isometric contraction was measured using a myograph and the phosphorylation level of myosin phosphatase target subunit 1 (MYPT1) was quantified by western blotting. The phenylephrine-induced contraction was enhanced by cooling to 24°C in tail arteries, but was suppressed in iliac arteries...
February 16, 2018: European Journal of Pharmacology
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