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Ameer OZ. Hypertension in chronic kidney disease: What lies behind the scene. Front Pharmacol 2022; 13:949260. [PMID: 36304157 PMCID: PMC9592701 DOI: 10.3389/fphar.2022.949260] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/26/2022] [Indexed: 12/04/2022] Open
Abstract
Hypertension is a frequent condition encountered during kidney disease development and a leading cause in its progression. Hallmark factors contributing to hypertension constitute a complexity of events that progress chronic kidney disease (CKD) into end-stage renal disease (ESRD). Multiple crosstalk mechanisms are involved in sustaining the inevitable high blood pressure (BP) state in CKD, and these play an important role in the pathogenesis of increased cardiovascular (CV) events associated with CKD. The present review discusses relevant contributory mechanisms underpinning the promotion of hypertension and their consequent eventuation to renal damage and CV disease. In particular, salt and volume expansion, sympathetic nervous system (SNS) hyperactivity, upregulated renin–angiotensin–aldosterone system (RAAS), oxidative stress, vascular remodeling, endothelial dysfunction, and a range of mediators and signaling molecules which are thought to play a role in this concert of events are emphasized. As the control of high BP via therapeutic interventions can represent the key strategy to not only reduce BP but also the CV burden in kidney disease, evidence for major strategic pathways that can alleviate the progression of hypertensive kidney disease are highlighted. This review provides a particular focus on the impact of RAAS antagonists, renal nerve denervation, baroreflex stimulation, and other modalities affecting BP in the context of CKD, to provide interesting perspectives on the management of hypertensive nephropathy and associated CV comorbidities.
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Affiliation(s)
- Omar Z. Ameer
- Department of Pharmaceutical Sciences, College of Pharmacy, Alfaisal University, Riyadh, Saudi Arabia
- Department of Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
- *Correspondence: Omar Z. Ameer,
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2
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Li S, Hildreth CM, Rahman AA, Barton SA, Wyse BF, Lim CK, Pilowsky PM, Phillips JK. Renal denervation does not affect hypertension or the renin-angiotensin system in a rodent model of juvenile-onset polycystic kidney disease: clinical implications. Sci Rep 2021; 11:14286. [PMID: 34253766 PMCID: PMC8275789 DOI: 10.1038/s41598-021-93575-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 06/21/2021] [Indexed: 12/17/2022] Open
Abstract
We examined the effect of total and afferent renal denervation (RDN) on hypertension and the renin-angiotensin system (RAS) in a rodent model of juvenile-onset polycystic kidney disease (PKD). Lewis Polycystic Kidney (LPK) and control rats received total, afferent or sham RDN by periaxonal application of phenol, capsaicin or normal saline, respectively, and were monitored for 4-weeks. Afferent RDN did not affect systolic blood pressure (SBP) determined by radiotelemetry in either strain (n = 19) while total RDN significantly reduced SBP in Lewis rats 4-weeks post-denervation (total vs. sham, 122 ± 1 vs. 130 ± 2 mmHg, P = 0.002, n = 25). Plasma and kidney renin content determined by radioimmunoassay were significantly lower in LPK vs. Lewis (plasma: 278.2 ± 6.7 vs. 376.5 ± 11.9 ng Ang I/ml/h; kidney: 260.1 ± 6.3 vs. 753.2 ± 37.9 ng Ang I/mg/h, P < 0.001, n = 26). These parameters were not affected by RDN. Intrarenal mRNA expression levels of renin, angiotensinogen, angiotensin-converting enzyme (ACE)2, and angiotensin II receptor type 1a were significantly lower, whereas ACE1 expression was significantly higher in the LPK vs. Lewis (all P < 0.05, n = 26). This pattern of intrarenal RAS expression was not changed by RDN. In conclusion, RDN does not affect hypertension or the RAS in the LPK model and indicates RDN might not be a suitable antihypertensive strategy for individuals with juvenile-onset PKD.
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Affiliation(s)
- Sheran Li
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Cara M Hildreth
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Ahmed A Rahman
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Sean A Barton
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Benjamin F Wyse
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Chai K Lim
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Paul M Pilowsky
- Discipline of Physiology, School of Medical Sciences, University of Sydney, Sydney, Australia
| | - Jacqueline K Phillips
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
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Saha M, Sun QJ, Hildreth CM, Burke PGR, Phillips JK. Augmented Respiratory-Sympathetic Coupling and Hemodynamic Response to Acute Mild Hypoxia in Female Rodents With Chronic Kidney Disease. Front Physiol 2021; 12:623599. [PMID: 34113258 PMCID: PMC8185289 DOI: 10.3389/fphys.2021.623599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/15/2021] [Indexed: 11/15/2022] Open
Abstract
Carotid body feedback and hypoxia may serve to enhance respiratory–sympathetic nerve coupling (respSNA) and act as a driver of increased blood pressure. Using the Lewis polycystic kidney (LPK) rat model of chronic kidney disease, we examined respSNA in adult female rodents with CKD and their response to acute hypoxia or hypercapnia compared to Lewis control animals. Under urethane anesthesia, phrenic nerve activity, splanchnic sympathetic nerve activity (sSNA), and renal sympathetic nerve activity (rSNA) were recorded under baseline conditions and during mild hypoxic or hypercapnic challenges. At baseline, tonic SNA and blood pressure were greater in female LPK rats versus Lewis rats (all P < 0.05) and respSNA was at least two-fold larger [area under the curve (AUC), sSNA: 7.8 ± 1.1 vs. 3.4 ± 0.7 μV s, rSNA: 11.5 ± 3 vs. 4.8 ± 0.7 μV s, LPK vs. Lewis, both P < 0.05]. Mild hypoxia produced a larger pressure response in LPK [Δ mean arterial pressure (MAP) 30 ± 6 vs. 12 ± 6 mmHg] and augmented respSNA (ΔAUC, sSNA: 8.9 ± 3.4 vs. 2 ± 0.7 μV s, rSNA: 6.1 ± 1.2 vs. 3.1 ± 0.7 μV s, LPK vs. Lewis, all P ≤ 0.05). In contrast, central chemoreceptor stimulation produced comparable changes in blood pressure and respSNA (ΔMAP 13 ± 3 vs. 9 ± 5 mmHg; respSNA ΔAUC, sSNA: 2.5 ± 1 vs. 1.3 ± 0.7 μV s, rSNA: 4.2 ± 0.9 vs. 3.5 ± 1.4 μV s, LPK vs. Lewis, all P > 0.05). These results demonstrate that female rats with CKD exhibit heightened respSNA coupling at baseline that is further augmented by mild hypoxia, and not by hypercapnia. This mechanism may be a contributing driver of hypertension in this animal model of CKD.
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Affiliation(s)
- Manash Saha
- Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia.,Department of Nephrology, National Institute of Kidney Disease and Urology, Dhaka, Bangladesh.,Graduate School of Medicine, Wollongong University, Wollongong, NSW, Australia
| | - Qi-Jian Sun
- Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia
| | - Cara M Hildreth
- Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia
| | - Peter G R Burke
- Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
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Underwood CF, Mcmullan S, Goodchild AK, Phillips JK, Hildreth CM. The subfornical organ drives hypertension in polycystic kidney disease via the hypothalamic paraventricular nucleus. Cardiovasc Res 2021; 118:1138-1149. [PMID: 33774660 DOI: 10.1093/cvr/cvab122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/25/2021] [Indexed: 11/14/2022] Open
Abstract
AIMS Hypertension is a prevalent yet poorly understood feature of polycystic kidney disease. Previously we demonstrated that increased glutamatergic neurotransmission within the hypothalamic paraventricular nucleus produces hypertension in the Lewis Polycystic Kidney rat model of polycystic kidney disease. Here we tested the hypothesis that augmented glutamatergic drive to the paraventricular nucleus in Lewis Polycystic Kidney rats originates from the forebrain lamina terminalis, a sensory structure that relays blood-borne information throughout the brain. METHODS AND RESULTS Anatomical experiments revealed that 38% of paraventricular nucleus-projecting neurons in the subfornical organ of the lamina terminalis expressed Fos/Fra, an activation marker, in Lewis Polycystic Kidney rats while <1% of neurons were Fos/Fra+ in Lewis control rats (P = 0.01, n = 8). In anaesthetised rats, subfornical organ neuronal inhibition using isoguvacine produced a greater reduction in systolic blood pressure in the Lewis Polycystic Kidney versus Lewis rats (-21 ± 4 vs. -7 ± 2 mmHg, P < 0.01; n = 10), which could be prevented by prior blockade of paraventricular nucleus ionotropic glutamate receptors using kynurenic acid. Blockade of ionotropic glutamate receptors in the paraventricular nucleus produced an exaggerated depressor response in Lewis Polycystic Kidney relative to Lewis rats (-23 ± 4 vs. -2 ± 3 mmHg, P < 0.001; n = 13), which was corrected by prior inhibition of the subfornical organ with muscimol but unaffected by chronic systemic angiotensin II type I receptor antagonism or lowering of plasma hyperosmolality through high-water intake (P > 0.05); treatments that both nevertheless lowered blood pressure in Lewis Polycystic Kidney rats (P < 0.0001). CONCLUSION Our data reveal multiple independent mechanisms contribute to hypertension in polycystic kidney disease, and identify high plasma osmolality, angiotensin II type I receptor activation and, importantly, a hyperactive subfornical organ to paraventricular nucleus glutamatergic pathway as potential therapeutic targets. TRANSLATIONAL PERSPECTIVE Hypertension is a significant comorbidity for all forms of chronic kidney disease and for individuals with polycystic kidney disease, often an early presenting feature. Nevertheless, the cause(s) of hypertension in polycystic kidney disease are poorly defined. Here we define the contribution of a neural pathway that contributes to hypertension in polycystic kidney disease. Critically, targeting this pathway may provide an additional antihypertensive effect beyond that achieved with current conventional antihypertensive therapies. Future work identifying the drivers of this neural pathway will aid in the development of newer generation antihypertensive medication.
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Affiliation(s)
- Conor F Underwood
- Department of Biomedical Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, AUSTRALIA.,Department of Anatomy, School of Biomedical Sciences, University of Otago, Otago, NEW ZEALAND
| | - Simon Mcmullan
- Department of Biomedical Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, AUSTRALIA
| | - Ann K Goodchild
- Department of Biomedical Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, AUSTRALIA
| | - Jacqueline K Phillips
- Department of Biomedical Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, AUSTRALIA
| | - Cara M Hildreth
- Department of Biomedical Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, AUSTRALIA
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Sata Y, Burke SL, Gueguen C, Lim K, Watson AM, Jha JC, Eikelis N, Jackson KL, Lambert GW, Denton KM, Schlaich MP, Head GA. Contribution of the Renal Nerves to Hypertension in a Rabbit Model of Chronic Kidney Disease. Hypertension 2020; 76:1470-1479. [DOI: 10.1161/hypertensionaha.120.15769] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Overactivity of the sympathetic nervous system and high blood pressure are implicated in the development and progression of chronic kidney disease (CKD) and independently predict cardiovascular events in end-stage renal disease. To assess the role of renal nerves, we determined whether renal denervation (RDN) altered the hypertension and sympathoexcitation associated with a rabbit model of CKD. The model involves glomerular layer lesioning and uninephrectomy, resulting in renal function reduced by one-third and diuresis. After 3-week CKD, blood pressure was 13±2 mm Hg higher than at baseline (P<0.001), and compared with sham control rabbits, renal sympathetic nerve activity was 1.2±0.5 normalized units greater (P=0.01). The depressor response to ganglion blockade was also +8.0±3 mm Hg greater, but total norepinephrine spillover was 8.7±3.7 ng/min lower (bothP<0.05). RDN CKD rabbits only increased blood pressure by 8.0±1.5 mm Hg. Renal sympathetic activity, the response to ganglion blockade and diuresis were similar to sham denervated rabbits (non-CKD). CKD rabbits had intact renal sympathetic baroreflex gain and range, as well as normal sympathetic responses to airjet stress. However, hypoxia-induced sympathoexcitation was reduced by −9±0.4 normalized units. RDN did not alter the sympathetic response to hypoxia or airjet stress. CKD increased oxidative stress markers Nox5 and MCP-1 (monocyte chemoattractant protein-1) in the kidney, but RDN had no effect on these measures. Thus, RDN is an effective treatment for hypertension in this model of CKD without further impairing renal function or altering the normal sympathetic reflex responses to various environmental stimuli.
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Affiliation(s)
- Yusuke Sata
- From the Neuropharmacology Laboratory (Y.S., S.L.B., C.G., K.L., K.L.J., G.A.H.), Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Human Neurotransmitters Laboratory (Y.S., M.P.S.), Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Faculty of Medicine, Nursing and Health Sciences, Central Clinical School (Y.S.), Monash University, Melbourne, VIC, Australia
- Department of Cardiology, Alfred Hospital, Melbourne, VIC, Australia (Y.S.)
| | - Sandra L. Burke
- From the Neuropharmacology Laboratory (Y.S., S.L.B., C.G., K.L., K.L.J., G.A.H.), Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Cindy Gueguen
- From the Neuropharmacology Laboratory (Y.S., S.L.B., C.G., K.L., K.L.J., G.A.H.), Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Kyungjoon Lim
- From the Neuropharmacology Laboratory (Y.S., S.L.B., C.G., K.L., K.L.J., G.A.H.), Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia (K.L.)
| | - Anna M.D. Watson
- Department of Diabetes, Central Clinical School (A.M.D.W., J.C.J.), Monash University, Melbourne, VIC, Australia
| | - Jay C. Jha
- Department of Diabetes, Central Clinical School (A.M.D.W., J.C.J.), Monash University, Melbourne, VIC, Australia
| | - Nina Eikelis
- Iverson Health Innovation Research Institute and School of Health Science, Swinburne University of Technology, Hawthorn, VIC, Australia (N.E., G.W.L.)
| | - Kristy L. Jackson
- From the Neuropharmacology Laboratory (Y.S., S.L.B., C.G., K.L., K.L.J., G.A.H.), Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Gavin W. Lambert
- Iverson Health Innovation Research Institute and School of Health Science, Swinburne University of Technology, Hawthorn, VIC, Australia (N.E., G.W.L.)
| | - Kate M. Denton
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia (K.M.D.)
| | - Markus P. Schlaich
- Human Neurotransmitters Laboratory (Y.S., M.P.S.), Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Dobney Hypertension Centre, School of Medicine, Royal Perth Hospital Unit, University of Western Australia (M.P.S.)
- Departments of Cardiology (M.P.S.), Royal Perth Hospital, Western Australia, Australia
- Nephrology (M.P.S.), Royal Perth Hospital, Western Australia, Australia
| | - Geoffrey A. Head
- From the Neuropharmacology Laboratory (Y.S., S.L.B., C.G., K.L., K.L.J., G.A.H.), Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Pharmacology (G.A.H.), Monash University, Melbourne, VIC, Australia
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6
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Differential sympathetic response to lesion-induced chronic kidney disease in rabbits. Kidney Int 2020; 98:906-917. [DOI: 10.1016/j.kint.2020.03.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/17/2020] [Accepted: 03/26/2020] [Indexed: 01/29/2023]
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Saha M, Menuet C, Sun QJ, Burke PGR, Hildreth CM, Allen AM, Phillips JK. Respiratory sympathetic modulation is augmented in chronic kidney disease. Respir Physiol Neurobiol 2019; 262:57-66. [PMID: 30721752 DOI: 10.1016/j.resp.2019.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/25/2019] [Accepted: 02/01/2019] [Indexed: 11/24/2022]
Abstract
Respiratory modulation of sympathetic nerve activity (respSNA) was studied in a hypertensive rodent model of chronic kidney disease (CKD) using Lewis Polycystic Kidney (LPK) rats and Lewis controls. In adult animals under in vivo anaesthetised conditions (n = 8-10/strain), respiratory modulation of splanchnic and renal nerve activity was compared under control conditions, and during peripheral (hypoxia), and central, chemoreceptor (hypercapnia) challenge. RespSNA was increased in the LPK vs. Lewis (area under curve (AUC) splanchnic and renal: 8.7 ± 1.1 vs. 3.5 ± 0.5 and 10.6 ± 1.1 vs. 7.1 ± 0.2 μV.s, respectively, P < 0.05). Hypoxia and hypercapnia increased respSNA in both strains but the magnitude of the response was greater in LPK, particularly in response to hypoxia. In juvenile animals studied using a working heart brainstem preparation (n = 7-10/strain), increased respSNA was evident in the LPK (thoracic SNA, AUC: 0.86 ± 0.1 vs. 0.42 ± 0.1 μV.s, P < 0.05), and activation of peripheral chemoreceptors (NaCN) again drove a larger increase in respSNA in the LPK with no difference in the response to hypercapnia. Amplified respSNA occurs in CKD and may contribute to the development of hypertension.
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Affiliation(s)
- Manash Saha
- Department of Biomedical Sciences, Macquarie University, Australia; Department of Nephrology, National Institute of Kidney Disease and Urology, Bangladesh; Graduate School of Medicine, Wollongong University, Australia; Department of Medicine, Wollongong Hospital, Australia
| | - Clement Menuet
- Department of Physiology, University of Melbourne, Australia; Institut de Neurobiologie de la Méditerranée, INMED UMR1249, INSERM, Aix-Marseille Université, Marseille, France
| | - Qi-Jian Sun
- Department of Biomedical Sciences, Macquarie University, Australia
| | | | - Cara M Hildreth
- Department of Biomedical Sciences, Macquarie University, Australia
| | - Andrew M Allen
- Department of Physiology, University of Melbourne, Australia
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Gao H, Korim WS, Yao ST, Heesch CM, Derbenev AV. Glycinergic neurotransmission in the rostral ventrolateral medulla controls the time course of baroreflex-mediated sympathoinhibition. J Physiol 2018; 597:283-301. [PMID: 30312491 DOI: 10.1113/jp276467] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 10/11/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS To maintain appropriate blood flow to various tissues of the body under a variety of physiological states, autonomic nervous system reflexes regulate regional sympathetic nerve activity and arterial blood pressure. Our data obtained in anaesthetized rats revealed that glycine released in the rostral ventrolateral medulla (RVLM) plays a critical role in maintaining arterial baroreflex sympathoinhibition. Manipulation of brainstem nuclei with known inputs to the RVLM (nucleus tractus solitarius and caudal VLM) unmasked tonic glycinergic inhibition in the RVLM. Whole-cell, patch clamp recordings demonstrate that both GABA and glycine inhibit RVLM neurons. Potentiation of neurotransmitter release from the active synaptic inputs in the RVLM produced saturation of GABAergic inhibition and emergence of glycinergic inhibition. Our data suggest that GABA controls threshold excitability, wherreas glycine increases the strength of inhibition under conditions of increased synaptic activity within the RVLM. ABSTRACT The arterial baroreflex is a rapid negative-feedback system that compensates changes in blood pressure by adjusting the output of presympathetic neurons in the rostral ventrolateral medulla (RVLM). GABAergic projections from the caudal VLM (CVLM) provide a primary inhibitory input to presympathetic RVLM neurons. Although glycine-dependent regulation of RVLM neurons has been proposed, its role in determining RVLM excitability is ill-defined. The present study aimed to determine the physiological role of glycinergic neurotransmission in baroreflex function, identify the mechanisms for glycine release, and evaluate co-inhibition of RVLM neurons by GABA and glycine. Microinjection of the glycine receptor antagonist strychnine (4 mm, 100 nL) into the RVLM decreased the duration of baroreflex-mediated inhibition of renal sympathetic nerve activity (control = 12 ± 1 min; RVLM-strychnine = 5.1 ± 1 min), suggesting that RVLM glycine plays a critical role in regulating the time course of sympathoinhibition. Blockade of output from the nucleus tractus solitarius and/or disinhibition of the CVLM unmasked tonic glycinergic inhibition of the RVLM. To evaluate cellular mechanisms, RVLM neurons were retrogradely labelled (prior injection of pseudorabies virus PRV-152) and whole-cell, patch clamp recordings were obtained in brainstem slices. Under steady-state conditions GABAergic inhibition of RVLM neurons predominated and glycine contributed less than 25% of the overall inhibition. By contrast, stimulation of synaptic inputs in the RVLM decreased GABAergic inhibition to 53%; and increased glycinergic inhibition to 47%. Thus, under conditions of increased synaptic activity in the RVLM, glycinergic inhibition is recruited to strengthen sympathoinhibition.
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Affiliation(s)
- Hong Gao
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Willian S Korim
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Song T Yao
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Cheryl M Heesch
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Andrei V Derbenev
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, USA.,Brain Institute, Tulane University, New Orleans, LA, USA
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9
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Korim WS, Elsaafien K, Basser JR, Setiadi A, May CN, Yao ST. In renovascular hypertension, TNF-α type-1 receptors in the area postrema mediate increases in cardiac and renal sympathetic nerve activity and blood pressure. Cardiovasc Res 2018; 115:1092-1101. [DOI: 10.1093/cvr/cvy268] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 10/02/2018] [Accepted: 10/24/2018] [Indexed: 12/16/2022] Open
Affiliation(s)
- Willian S Korim
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
- Wade Institute of Entrepreneurship, University of Melbourne, Parkville, VIC, Australia
| | - Khalid Elsaafien
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Jeremy R Basser
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Anthony Setiadi
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Clive N May
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Song T Yao
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
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10
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Quek KJ, Ameer OZ, Phillips JK. AT1 Receptor Antagonism Improves Structural, Functional, and Biomechanical Properties in Resistance Arteries in a Rodent Chronic Kidney Disease Model. Am J Hypertens 2018; 31:696-705. [PMID: 29425281 DOI: 10.1093/ajh/hpy021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 02/06/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The renin-angiotensin system, in particular Angiotensin II (AngII), plays a significant role in the pathogenesis of hypertension in chronic kidney disease (CKD). Effects of chronic AT1 receptor antagonism were investigated in a genetic hypertensive rat model of CKD, the Lewis polycystic kidney (LPK) rat. METHODS Mixed-sex LPK and Lewis control rats (total n = 31) were split between treated (valsartan 60 mg/kg/day p.o. from 4 to 18 weeks) and vehicle groups. Animals were assessed for systolic blood pressure and urine biochemistry, and after euthanasia, blood collected for urea and creatinine analysis, confirming the hypertensive and renal phenotype. Mesenteric resistance vasculature was assessed using pressure myography and histology. RESULTS Valsartan treatment improved vascular structure in LPK rats, increasing internal and external diameter values and reducing wall thickness (untreated vs. treated LPK: 53.19 ± 3.29 vs. 33.93 ± 2.17 μm) and wall-lumen ratios (untreated vs. treated LPK: 0.52 ± 0.09 vs. 0.16 ± 0.01, all P < 0.0001). Endothelium dysfunction, as measured by maximal response to acetylcholine (Rmax), was normalized with treatment (untreated vs. treated LPK: 69.56 ± 4.34 vs. 103.05 ± 4.13, P < 0.05), increasing the relative contributions of nitric oxide and endothelium-derived hyperpolarization to vasorelaxation while downregulating the prostanoid contribution. Biomechanical properties also improved with treatment, as indicated by an increase in compliance, decrease in intrinsic stiffness and alterations in the artery wall composition, which included decreases in collagen density and collagen/elastin ratio. CONCLUSIONS Our results highlight the importance of AngII as a driver of resistance vessel structural, functional, and biomechanical dysfunction and provide insight as to how AT1 receptor blockade exerts therapeutic efficacy in CKD.
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Affiliation(s)
- Ko Jin Quek
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Omar Z Ameer
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
- Colleges of Medicine and Pharmacy, Alfaisal University, Riyadh, Kingdom of Saudi Arabia
| | - Jacqueline K Phillips
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
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Kandukuri DS, Phillips JK, Tahmindjis M, Hildreth CM. Effect of anaesthetic and choice of neuromuscular blocker on vagal control of heart rate under laboratory animal experimental conditions. Lab Anim 2017; 52:280-291. [PMID: 28862524 DOI: 10.1177/0023677217725365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
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. Pancuronium produced a profound vagolytic response characterized by tachycardia, reduction in heart rate variability and baroreflex sensitivity under urethane anaesthesia, and with minimal effect under isoflurane anaesthesia. Conversely, cisatracurium produced no evidence of vagolytic action under either urethane or isoflurane anaesthesia. Therefore, for studies interested in examining autonomic function, particularly baroreflex or vagal function, neuromuscular blockade would be best achieved using cisatracurium.
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Affiliation(s)
- Divya Sarma Kandukuri
- 1 Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Jacqueline K Phillips
- 1 Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Mark Tahmindjis
- 2 Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Cara M Hildreth
- 1 Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
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12
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Lincevicius GS, Shimoura CG, Nishi EE, Oliveira T, Cespedes JG, Bergamaschi CT, Campos RR. Differential effects of renal denervation on arterial baroreceptor function in Goldblatt hypertension model. Auton Neurosci 2017; 208:43-50. [PMID: 28688830 DOI: 10.1016/j.autneu.2017.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 06/09/2017] [Accepted: 06/19/2017] [Indexed: 01/19/2023]
Abstract
Sympathetic vasomotor activity is significantly increased in renovascular hypertension. Renal denervation (DnX) has emerged as a novel therapy for resistant hypertension to drug therapy. However, the underlying mechanisms regarding the reduction in blood pressure (BP) after DnX remain unclear. Thus, the aim of this study was to evaluate the effects of DnX of a clipped kidney on the baseline and baroreceptor reflex control of post-ganglionic sympathetic activity to the contralateral kidney (rSNA) and lumbar (lSNA) nerves in Goldblatt hypertensive rats (2K1C). Renal denervation of an ischaemic kidney (DxX - all visible bundles of nerves were dissected - 10% phenol) was performed 5weeks after clipping (gap width: 0.2mm). Ten days after DnX, BP was significantly reduced (16%) in the 2K1C compared with the undenervated 2K1C (p<0.05). DnX significantly reduced basal rSNA (control group (CT): 110±8, n=14; 2K1C: 150±8, n=12; 2K1C DnX: 89±7, spikes per second (spikes/s); p<0.05, n=8) and lSNA (CT: 137±8, n=8; 2K1C: 202±7, n=11; 2K1C DnX: 131±7, spikes/s; p<0.05, n=8) only in 2K1C rats. DnX significantly improved the arterial baroreceptor sensitivity of rSNA (CT: -2.3±0.2, n=11; 2K1C: -0.7±0.1, n=8; 2K1C DnX: -1.5±0.2, spikes/s/mmHg; p<0.05, n=5) and heart rate for tachycardic response (CT: -3.9±0.5, n=7; 2K1C: -1.9±0.1, n=8; 2K1C DnX: -3.3±0.4, bpm/mmHg; p<0.05, n=8), but not for lSNA in 2K1C rats. The results show that DnX normalized baseline sympathetic vasomotor activity to the lumbar and renal nerves, followed by a differential improvement in the arterial baroreceptor sensitivity. Whether the baroreceptor function sensitivity improvement induced by DnX is a cause or a consequence of BP reduction remains to be determined.
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Affiliation(s)
- Gisele S Lincevicius
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Caroline G Shimoura
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Erika E Nishi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Tales Oliveira
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Juliana G Cespedes
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, Campus São José dos Campos, Brazil
| | - Cássia T Bergamaschi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Ruy R Campos
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil.
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13
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Total renal denervation reduces sympathoexcitation to different target organs in a model of chronic kidney disease. Auton Neurosci 2017; 204:81-87. [DOI: 10.1016/j.autneu.2016.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 12/28/2022]
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14
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Underwood CF, Hildreth CM, Wyse BF, Boyd R, Goodchild AK, Phillips JK. Uraemia: an unrecognized driver of central neurohumoral dysfunction in chronic kidney disease? Acta Physiol (Oxf) 2017; 219:305-323. [PMID: 27247097 DOI: 10.1111/apha.12727] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 01/21/2016] [Accepted: 05/31/2016] [Indexed: 12/12/2022]
Abstract
Chronic kidney disease (CKD) carries a large cardiovascular burden in part due to hypertension and neurohumoral dysfunction - manifesting as sympathetic overactivity, baroreflex dysfunction and chronically elevated circulating vasopressin. Alterations within the central nervous system (CNS) are necessary for the expression of neurohumoral dysfunction in CKD; however, the underlying mechanisms are poorly defined. Uraemic toxins are a diverse group of compounds that accumulate as a direct result of renal disease and drive dysfunction in multiple organs, including the brain. Intensive haemodialysis improves both sympathetic overactivity and cardiac baroreflex sensitivity in renal failure patients, indicating that uraemic toxins participate in the maintenance of autonomic dysfunction in CKD. In rodents exposed to uraemia, immediate early gene expression analysis suggests upregulated activity of not only pre-sympathetic but also vasopressin-secretory nuclei. We outline several potential mechanisms by which uraemia might drive neurohumoral dysfunction in CKD. These include superoxide-dependent effects on neural activity, depletion of nitric oxide and induction of low-grade systemic inflammation. Recent evidence has highlighted superoxide production as an intermediate for the depolarizing effect of some uraemic toxins on neuronal cells. We provide preliminary data indicating augmented superoxide production within the hypothalamic paraventricular nucleus in the Lewis polycystic kidney rat, which might be important for mediating the neurohumoral dysfunction exhibited in this CKD model. We speculate that the uraemic state might serve to sensitize the central actions of other sympathoexcitatory factors, including renal afferent nerve inputs to the CNS and angiotensin II, by way of recruiting convergent superoxide-dependent and pro-inflammatory pathways.
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Affiliation(s)
- C. F. Underwood
- Department of Biomedical Sciences; Macquarie University; Sydney NSW Australia
| | - C. M. Hildreth
- Department of Biomedical Sciences; Macquarie University; Sydney NSW Australia
| | - B. F. Wyse
- Department of Biomedical Sciences; Macquarie University; Sydney NSW Australia
| | - R. Boyd
- Department of Biomedical Sciences; Macquarie University; Sydney NSW Australia
| | - A. K. Goodchild
- Department of Biomedical Sciences; Macquarie University; Sydney NSW Australia
| | - J. K. Phillips
- Department of Biomedical Sciences; Macquarie University; Sydney NSW Australia
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15
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Kuczeriszka M, Dobrowolski L, Walkowska A, Sadowski J. Influence of P2X receptors on renal medullary circulation is not altered by angiotensin II pretreatment. Pharmacol Rep 2016; 68:1230-1236. [DOI: 10.1016/j.pharep.2016.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/20/2016] [Accepted: 07/29/2016] [Indexed: 12/26/2022]
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16
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Salman IM, Hildreth CM, Phillips JK. Chronic kidney disease impairs renal nerve and haemodynamic reflex responses to vagal afferent input through a central mechanism. Auton Neurosci 2016; 204:65-73. [PMID: 27776979 DOI: 10.1016/j.autneu.2016.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/20/2016] [Accepted: 10/08/2016] [Indexed: 11/25/2022]
Abstract
We investigated age- and sex-related changes in reflex renal sympathetic nerve activity (RSNA) and haemodynamic responses to vagal afferent stimulation in a rodent model of chronic kidney disease (CKD). Using anaesthetised juvenile (7-8weeks) and adult (12-13weeks) Lewis Polycystic Kidney (LPK) and Lewis control rats of either sex (n=63 total), reflex changes in RSNA, heart rate (HR) and mean arterial pressure (MAP) to vagal afferent stimulation (5-s train, 4.0V, 2.0-ms pulses, 1-16Hz) were measured. In all groups, stimulation of the vagal afferents below 16Hz produced frequency-dependent reductions in RSNA, HR and MAP, while a 16Hz stimulus produced an initial sympathoinhibition followed by sympathoexcitation. In juvenile LPK versus age-matched Lewis, sympathoinhibition was reduced when responses were expressed as % baseline (P<0.05), but not as microvolts, while bradycardic responses were greater. Reflex depressor responses were greater (P=0.015) only in juvenile female LPK. In adult LPK, reflex sympathoinhibition (%) was blunted (P<0.05), and an age-related decline apparent (when expressed as microvolts). Reflex reductions in HR and MAP were only diminished (P<0.05) in adult female LPK versus age-matched Lewis. Peak reflex sympathoexcitation at 16Hz did not differ between groups; however, area under the curve values were greater in the LPK versus Lewis (overall, 9±1 versus 19±3μVs, P<0.05) irrespective of age, suggestive of enhanced sympathoexcitatory drive in the LPK. Our data demonstrates a progressive deficit in the central processing of vagal afferent input and a differential sex influence on reflex regulation of autonomic function and blood pressure homeostasis in CKD.
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Affiliation(s)
- Ibrahim M Salman
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Cara M Hildreth
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Jacqueline K Phillips
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
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17
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Salman IM. Current Approaches to Quantifying Tonic and Reflex Autonomic Outflows Controlling Cardiovascular Function in Humans and Experimental Animals. Curr Hypertens Rep 2016; 17:84. [PMID: 26363932 DOI: 10.1007/s11906-015-0597-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of the autonomic nervous system in the pathophysiology of human and experimental models of cardiovascular disease is well established. In the recent years, there have been some rapid developments in the diagnostic approaches used to assess and monitor autonomic functions. Although most of these methods are devoted for research purposes in laboratory animals, many have still found their way to routine clinical practice. To name a few, direct long-term telemetry recording of sympathetic nerve activity (SNA) in rodents, single-unit SNA recording using microneurography in human subjects and spectral analysis of blood pressure and heart rate in both humans and animals have recently received an overwhelming attention. In this article, we therefore provide an overview of the methods and techniques used to assess tonic and reflex autonomic functions in humans and experimental animals, highlighting current advances available and procedure description, limitations and usefulness for diagnostic purposes.
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Affiliation(s)
- Ibrahim M Salman
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia.
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18
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Salman IM. Cardiovascular Autonomic Dysfunction in Chronic Kidney Disease: a Comprehensive Review. Curr Hypertens Rep 2016; 17:59. [PMID: 26071764 DOI: 10.1007/s11906-015-0571-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cardiovascular autonomic dysfunction is a major complication of chronic kidney disease (CKD), likely contributing to the high incidence of cardiovascular mortality in this patient population. In addition to adrenergic overdrive in affected individuals, clinical and experimental evidence now strongly indicates the presence of impaired reflex control of both sympathetic and parasympathetic outflow to the heart and vasculature. Although the principal underlying mechanisms are not completely understood, potential involvements of altered baroreceptor, cardiopulmonary, and chemoreceptor reflex function, along with factors including but not limited to increased renin-angiotensin-aldosterone system activity, activation of the renal afferents and cardiovascular structural remodeling have been suggested. This review therefore analyzes potential mechanisms underpinning autonomic imbalance in CKD, covers results accumulated thus far on cardiovascular autonomic function studies in clinical and experimental renal failure, discusses the role of current interventional and therapeutic strategies in ameliorating autonomic deficits associated with chronic renal dysfunction, and identifies gaps in our knowledge of neural mechanisms driving cardiovascular disease in CKD.
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Affiliation(s)
- Ibrahim M Salman
- The Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia,
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19
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Salman IM, Sarma Kandukuri D, Harrison JL, Hildreth CM, Phillips JK. Direct conscious telemetry recordings demonstrate increased renal sympathetic nerve activity in rats with chronic kidney disease. Front Physiol 2015; 6:218. [PMID: 26300784 PMCID: PMC4523722 DOI: 10.3389/fphys.2015.00218] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/20/2015] [Indexed: 01/05/2023] Open
Abstract
Chronic kidney disease (CKD) is associated with sympathetic hyperactivity and impaired blood pressure control reflex responses, yet direct evidence demonstrating these features of autonomic dysfunction in conscious animals is still lacking. Here we measured renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) using telemetry-based recordings in a rat model of CKD, the Lewis Polycystic Kidney (LPK) rat, and assessed responses to chemoreflex activation and acute stress. Male LPK and Lewis control animals (total n = 16) were instrumented for telemetric recording of RSNA and MAP. At 12–13 weeks-of-age, resting RSNA and MAP, sympathetic and haemodynamic responses to both peripheral (hypoxia: 10% O2) and central chemoreflex (hypercapnia: 7% CO2) activation and acute stress (open-field exposure), were measured. As indicators of renal function, urinary protein (UPro) and creatinine (UCr) levels were assessed. LPK rats had higher resting RSNA (1.2 ± 0.1 vs. 0.6 ± 0.1 μV, p < 0.05) and MAP (151 ± 8 vs. 97 ± 2 mmHg, p < 0.05) compared to Lewis. MAP was negatively correlated with UCr (r = −0.80, p = 0.002) and positively correlated with RSNA (r = 0.66, p = 0.014), with multiple linear regression modeling indicating the strongest correlation was with Ucr. RSNA and MAP responses to activation of the central chemoreflex and open-field stress were reduced in the LPK relative to the Lewis (all p < 0.05). This is the first description of dual conscious telemetry recording of RSNA and MAP in a genetic rodent model of CKD. Elevated RSNA is likely a key contributor to the marked hypertension in this model, while attenuated RSNA and MAP responses to central chemoreflex activation and acute stress in the LPK indicate possible deficits in the neural processing of autonomic outflows evoked by these sympathoexcitatory pathways.
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Affiliation(s)
- Ibrahim M Salman
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
| | - Divya Sarma Kandukuri
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
| | - Joanne L Harrison
- School of Veterinary and Life Sciences, Murdoch University Murdoch, WA, Australia
| | - Cara M Hildreth
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
| | - Jacqueline K Phillips
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
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Shuangxia F, Zheng G, Yelv T, Hui L, Guofang J. An Efficient and Green Synthetic Route to Losartan. JOURNAL OF CHEMICAL RESEARCH 2015. [DOI: 10.3184/174751915x14379907479622] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A practical, efficient and green process for the preparation of losartan, an antihypertensive drug, has been developed with an overall yield of 58.6%. The key step is the synthesis of the two key intermediates 2-butyl-4-chloro-3H-imidazole-5-carbaldehyde (BCFI) and 2-cyano-4′-methyl biphenyl (OTBN). BCFI was synthesised from valeronitrile and acetyl chloride by three steps with an overall yield of 69%; OTBN was obtained in 86% yield by the coupling of o-chlorobenzonitrile with p-methylphenylmagnesium chloride in tetrahydrofuran in the presence of manganese chloride and chlorotrimethylsilane. The above route was successfully operated in at a pilot-plant operation.
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Affiliation(s)
- Feng Shuangxia
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Gu Zheng
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Tang Yelv
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Liu Hui
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Jiang Guofang
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
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