Abstract:
BACKGROUND AND PURPOSE:Resurgence in the use of chloroquine as a potential treatment for COVID-19 has seen recent cases of fatal toxicity due to unintentional overdoses. Protocols for the management of poisoning recommend diazepam, although there are uncertainties in its pharmacology and efficacy in this context. The aim was to assess the effects of diazepam in experimental models of chloroquine cardiotoxicity. EXPERIMENTAL APPROACH:In vitro experiments involved cardiac tissues isolated from rats and incubated with chloroquine alone or in combination with diazepam. In vivo models of toxicity involved chloroquine administered intravenously to pentobarbitone-anaesthetised rats and rabbits. Randomised, controlled treatment studies in rats assessed diazepam, clonazepam and Ro5-4864 administered: (i) prior, (ii) during and (iii) after chloroquine and the effects of diazepam: (iv) at high dose, (v) in urethane-anaesthetised rats and (vi) co-administered with adrenaline. KEY RESULTS:Chloroquine decreased the developed tension of left atria, prolonged the effective refractory period of atria, ventricular tissue and right papillary muscles, and caused dose-dependent impairment of haemodynamic and electrocardiographic parameters. Cardiac arrhythmias indicated impairment of atrioventricular conduction. Studies (i), (ii) and (v) showed no differences between treatments and control. Diazepam increased heart rate in study (iv) and as with clonazepam also prolonged the QTc interval in study (iii). Combined administration of diazepam and adrenaline in study (vi) improved cardiac contractility but caused hypokalaemia. CONCLUSION AND IMPLICATIONS:Neither diazepam nor other ligands for benzodiazepine binding sites protect against or attenuate chloroquine cardiotoxicity. However, diazepam may augment the effects of positive inotropes in reducing chloroquine cardiotoxicity. LINKED ARTICLES:This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.
journal_name
Br J Pharmacoljournal_title
British journal of pharmacologyauthors
Hughes DAdoi
10.1111/bph.15101subject
Has Abstractpub_date
2020-11-01 00:00:00pages
4975-4989issue
21eissn
0007-1188issn
1476-5381journal_volume
177pub_type
杂志文章abstract::1. The subtype of alpha1-adrenoceptor mediating contractions to phenylephrine of the rat thoracic aorta, mesenteric artery and pulmonary artery were investigated by use of antagonists which show selectivity between the cloned alpha1-adrenoceptor subtypes in binding studies. 2. Cumulative concentration-contraction curv...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0701461
更新日期:1997-11-01 00:00:00
abstract::Adenosine enhanced histamine release and prolonged the adenosine 3':5'-cyclic monophosphate (cyclic AMP) response in purified rat peritoneal mast cells following immunological challenge. The effect on the cyclic AMP response, which was blocked by 8-phenyltheophylline, probably results from an interaction with A2-purin...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1985.tb08823.x
更新日期:1985-05-01 00:00:00
abstract::1. Salmeterol is a potent, selective and long acting beta 2-adrenoceptor agonist. In vitro, salmeterol exerts 'reassertion' relaxation of airways smooth muscle. Reassertion relaxation refers to the capacity of salmeterol to cause repeated functional antagonism of induced contraction when airway smooth muscle is interm...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb16690.x
更新日期:1996-03-01 00:00:00
abstract::1. We showed earlier that NO inhibition caused a left-shift and augmented Emax of the concentration-response curve of AT1-mediated (angiotensin II)-induced vasoconstrictions (AII-VC) in the rat kidney. The 0.01-0.1 nM AII-VC unmasked by the potentiating effect of NO inhibition, were sensitive not only to AT1 (L158809)...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0701906
更新日期:1998-07-01 00:00:00
abstract::N-methyl-d-aspartate (NMDA) receptors have been demonstrated to be a pivotal target for ethanol action. The present study examined the actions of acute ethanol exposure on NMDA-induced responses and the acute tolerance to ethanol actions in rat sympathetic preganglionic neurons (SPNs) in vitro and in vivo. NMDA (50 mi...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0705512
更新日期:2003-11-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Due to their potent bronchodilator properties, beta(2)-adrenoceptor agonists are a mainstay of therapy in asthma. However, the effects of beta(2)-adrenoceptor agonists on inflammation are less clear. Accordingly, we have investigated the effects of beta(2)-adrenoceptor agonists on inflammatory me...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.2010.00708.x
更新日期:2010-05-01 00:00:00
abstract::A hallmark of heart failure is mitochondrial dysfunction leading to a bioenergetics imbalance in the myocardium. Consequently, there is much interest in targeting mitochondrial abnormalities to attenuate the pathogenesis of heart failure. This review discusses (i) how electron microscopy (EM) techniques have been fund...
journal_title:British journal of pharmacology
pub_type: 杂志文章,评审
doi:10.1111/bph.14499
更新日期:2019-11-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Red blood cells (RBCs) are reservoirs of vasodilatory, antiaggregatory, and antiinflammatory lipid mediators-epoxyeicosatrienoic acids (EETs). This study addresses the formation and release of erythrocyte-derived EETs in response to ATP receptor stimulation that may represent an important mechani...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0707311
更新日期:2007-08-01 00:00:00
abstract::1. In anaesthetized patients under controlled respiration, samples of lumbar cerebrospinal fluid were withdrawn 15 and 60 min after an intravenous injection of 30 mg tubocurarine. When tested on the frog rectus muscle preparation contracted by acetylcholine, they exerted curare-like activity which corresponded to betw...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1973.tb08206.x
更新日期:1973-04-01 00:00:00
abstract::In the clinic, low efficacy positive GABAA modulators might be preferred to high efficacy positive modulators insofar as low efficacy modulators might have comparatively less abuse and dependence liability. Drug discrimination was used to examine the behavioral effects of L-838,417 and bretazenil, two low efficacy pos...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0706550
更新日期:2006-02-01 00:00:00
abstract::1 The activity and pulmonary metabolism of two peptides, 7-homo Pro-bradykinin and 8-homo Phe-bradykinin were studied in isolated systems. 2 Both analogues were about 50-70 times less active than bradykinin on the guinea-pig ileum and 70-160 times less active on isolated strips of cat terminal ileum. 3 The action of b...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1977.tb06985.x
更新日期:1977-01-01 00:00:00
abstract::1. The present study was designed to characterize the nociceptive response induced by protein kinase C (PKC) peripheral activation and to investigate if this biochemical event is important for the nociceptive response induced by formaldehyde, and bradykinin (BK). 2. Intraplantar injection of phorbol-12,13-didecanoate ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704434
更新日期:2002-01-01 00:00:00
abstract::1. We have investigated the cellular target of K(+) channel blockers responsible for the inhibition of the EDHF-mediated relaxation in the rat mesenteric artery by studying their effects on tension, smooth muscle cell (SMC) membrane potential and endothelial cell Ca(2+) signal ([Ca(2+)](endo)). 2. In arteries contract...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704348
更新日期:2001-11-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation; somatostatin exerts systemic anti-inflammatory actions presumably via sst4/sst1 receptors. This study investigates the effects of a high affinity, sst...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0706876
更新日期:2006-10-01 00:00:00
abstract::1 The beta-adrenoceptor agonist isoprenaline normally causes only a small and inconsistent increase in the membrane potential of cells in guinea-pig liver slices, in contrast to the large hyperpolarizations seen with alpha-agonists. However, after a selective alpha-adrenoceptor agonist has been applied, the response t...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1977.tb06991.x
更新日期:1977-01-01 00:00:00
abstract::The neuroprotective drug riluzole has multiple effects on cellular signaling. We found that riluzole rapidly and reversibly inhibited spontaneous Ca2+ oscillations in both immortalized GnRH-secreting hypothalamic neurons (GT1 cells) and in the prolactin and growth-hormone-secreting GH3 cell line. At lower concentratio...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0705491
更新日期:2003-11-01 00:00:00
abstract::1 Synaptic potentials and the responses of frog spinal cord to various acidic amino acids were examined by means of the sucrose gap recording technique. 2 Divalent cations (50-250 microM) specifically antagonized responses evoked at N-methyl-D-aspartate (NMDA) receptors by N-methyl D,L aspartic acid (NMDLA). The rank ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1982.tb09306.x
更新日期:1982-10-01 00:00:00
abstract::1. Idioventricular rate responses and adrenoceptor number have been examined in normal Langendorff hearts perfused at 70 cmH2O and in 'ischaemic' hearts perfused at 10 cmH2O. 2. In hearts perfused at normal pressure, ventricular rate responses to phenylephrine in the presence of propranolol were biphasic with low conc...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1990.tb15860.x
更新日期:1990-07-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Saponins isolated from Panax notoginseng (Burk.) F.H. Chen have been shown to relieve thrombogenesis and facilitate haemostasis. However, it is not known which saponin accounts for this haemostatic effect. Hence, in the present study we aimed to identify which saponins contribute to its haemostat...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.12435
更新日期:2014-01-01 00:00:00
abstract::1. The effects of dopamine on the L-type Ca2+ current (ICa,L) of both atrial and ventricular single myocytes and on the force of contraction of atrial trabeculae in rat heart were investigated. 2. Dopamine increased atrial ICa,L at concentrations higher than 1 microM, but had little or no effect on ICa,L at lower conc...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0701250
更新日期:1997-08-01 00:00:00
abstract:BACKGROUND AND PURPOSE:There is increasing evidence that angiotensin II (Ang II) is associated with the occurrence of ventricular arrhythmias. However, little is known about the electrophysiological effects of Ang II on ventricular repolarization. The rapid component of the delayed rectifier K(+) current (I(Kr)) plays ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/bjp.2008.95
更新日期:2008-05-01 00:00:00
abstract::1. Mouse islets were used to define the characteristics and study the mechanisms of the stimulation of insulin release by compound AZ-DF 265, 4-[[N-(alpha-phenyl-2-piperidino-benzyl) carbamoyl]methyl] benzoic acid, a substituted benzoic acid with an asymmetric carbon atom. 2. At a non-stimulatory concentration of gluc...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1988.tb11405.x
更新日期:1988-01-01 00:00:00
abstract::Vasoactive intestinal peptide (VIP) caused concentration-dependent relaxation in precontracted segments of trachea, hilar bronchus, intrapulmonary bronchus and intrapulmonary artery (IPA) isolated from cat lungs. VIP-induced relaxation responses were abolished by preincubation of tissues with the proteolytic enzyme, a...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1984.tb10766.x
更新日期:1984-06-01 00:00:00
abstract::1. The interactive effects of different metabotropic glutamate (mGlu) receptor subtypes to regulate phosphoinositide turnover have been studied in neonatal rat cerebral cortex and hippocampus by use of agonists and antagonists selective between group I and II mGlu receptors. 2, The group II-selective agonist 2R,4R-4-a...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0701626
更新日期:1998-02-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Pulmonary arterial hypertension (PAH) is characterized by enhanced pulmonary vascular resistance, right ventricular hypertrophy and increased right ventricular systolic pressure. Here, we investigated the effects of a N-acylhydrazone derivative, 3,4-dimethoxyphenyl-N-methyl-benzoylhydrazide (LASS...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.12193
更新日期:2013-07-01 00:00:00
abstract::Irritable bowel syndrome is characterized by visceral hyperalgesia commonly associated with stress and inflammatory processes. We investigated the role of tachykinin NK2 receptors in the ability of trinitrobenzenesulphonic acid (TNBS) and stress to enhance the sensitivity of the rat rectum to distension using a select...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0703040
更新日期:2000-01-01 00:00:00
abstract:BACKGROUND AND PURPOSE:We investigated whether or not kinin receptors play a role in diabetic blood-retinal barrier breakdown, which is a leading cause of vision loss. EXPERIMENTAL APPROACH:Blood-retinal barrier breakdown was quantified using Evans blue, and expression of kinin B(1) receptor mRNA was measured using qu...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/bjp.2008.48
更新日期:2008-05-01 00:00:00
abstract::1. It has previously been shown that the antimigraine drug, sumatriptan, a putative 5-HT1D receptor agonist, decreases porcine common carotid and arteriovenous anastomotic blood flows, but slightly increases the arteriolar (capillary) blood flow to the skin and ears. Interestingly, such responses, being mediated by 5-...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb15370.x
更新日期:1996-05-01 00:00:00
abstract:BACKGROUND AND PURPOSE:The chemokine receptor CXCR3 directs migration of T-cells in response to the ligands CXCL9/Mig, CXCL10/IP-10 and CXCL11/I-TAC. Both ligands and receptors are implicated in the pathogenesis of inflammatory disorders, including atherosclerosis and rheumatoid arthritis. Here, we describe the molecul...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.2011.01660.x
更新日期:2012-06-01 00:00:00
abstract::(1) Increased oxidative stress plays a significant role in the etiology of cardiovascular disease. Lipid peroxidation, initiated in the presence of hydroxy radicals resulting in the production of malondialdehyde, directly produces oxidative stress. This study was designed to examine the direct impact of malondialdehyd...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0705384
更新日期:2003-08-01 00:00:00