1
|
Mizuno M, Hotta N, Ishizawa R, Kim HK, Iwamoto G, Vongpatanasin W, Mitchell JH, Smith SA. The Impact of Insulin Resistance on Cardiovascular Control During Exercise in Diabetes. Exerc Sport Sci Rev 2021; 49:157-167. [PMID: 33965976 PMCID: PMC8195845 DOI: 10.1249/jes.0000000000000259] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Patients with diabetes display heightened blood pressure response to exercise, but the underlying mechanism remains to be elucidated. There is no direct evidence that insulin resistance (hyperinsulinemia or hyperglycemia) impacts neural cardiovascular control during exercise. We propose a novel paradigm in which hyperinsulinemia or hyperglycemia significantly influences neural regulatory pathways controlling the circulation during exercise in diabetes.
Collapse
Affiliation(s)
- Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Norio Hotta
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Gary Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Jere H. Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Scott A. Smith
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| |
Collapse
|
2
|
Hao HF, Liu LM, Pan CS, Wang CS, Gao YS, Fan JY, Han JY. Rhynchophylline Ameliorates Endothelial Dysfunction via Src-PI3K/Akt-eNOS Cascade in the Cultured Intrarenal Arteries of Spontaneous Hypertensive Rats. Front Physiol 2017; 8:928. [PMID: 29187825 PMCID: PMC5694770 DOI: 10.3389/fphys.2017.00928] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/01/2017] [Indexed: 11/13/2022] Open
Abstract
Objectives: To examine the protective effect of Rhynchophylline (Rhy) on vascular endothelial function in spontaneous hypertensive rats (SHRs) and the underlying mechanism. Methods: Intrarenal arteries of SHRs and Wistar rats were suspended in myograph for force measurement. Expression and phosphorylation of endothelial nitric oxide (NO) synthase (eNOS), Akt, and Src kinase (Src) were examined by Western blotting. NO production was assayed by ELISA. Results: Rhy time- and concentration-dependently improved endothelium-dependent relaxation in the renal arteries from SHRs, but had no effect on endothelium-independent relaxation in SHR renal arteries. Wortmannin (an inhibitor of phosphatidylinositol 3-kinase) or PP2 (an inhibitor of Src) inhibited the improvement of relaxation in response to acetylcholine by 12 h-incubation with 300 μM Rhy. Western blot analysis revealed that Rhy elevated phosphorylations of eNOS, Akt, and Src in SHR renal arteries. Moreover, wortmannin reversed the increased phosphorylations of Akt and eNOS induced by Rhy, but did not affect the phosphorylation of Src. Furthermore, the enhanced phosphorylations of eNOS, Akt, and Src were blunted by PP2. Importantly, Rhy increased NO production and this effect was blocked by inhibition of Src or PI3K/Akt. Conclusion: The present study provides evidences for the first time that Rhy ameliorates endothelial dysfunction in SHRs through the activation of Src-PI3K/Akt-eNOS signaling pathway.
Collapse
Affiliation(s)
- Hui-Feng Hao
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China.,Department of Integration of Chinese and Western Medicine, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Li-Mei Liu
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Chun-Shui Pan
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China.,Key Laboratory of Microcirculation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Beijing, China.,Key Laboratory of Stasis and Phlegm, State Administration of Traditional Chinese Medicine of the People's Republic of China, Beijing, China.,State Key Laboratory of Core Technology in Innovative Chinese Medicine, Beijing, China
| | - Chuan-She Wang
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China.,Department of Integration of Chinese and Western Medicine, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Microcirculation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Beijing, China.,Key Laboratory of Stasis and Phlegm, State Administration of Traditional Chinese Medicine of the People's Republic of China, Beijing, China.,State Key Laboratory of Core Technology in Innovative Chinese Medicine, Beijing, China
| | - Yuan-Sheng Gao
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Jing-Yu Fan
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China.,Key Laboratory of Microcirculation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Beijing, China.,Key Laboratory of Stasis and Phlegm, State Administration of Traditional Chinese Medicine of the People's Republic of China, Beijing, China.,State Key Laboratory of Core Technology in Innovative Chinese Medicine, Beijing, China
| | - Jing-Yan Han
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China.,Department of Integration of Chinese and Western Medicine, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Microcirculation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Beijing, China.,Key Laboratory of Stasis and Phlegm, State Administration of Traditional Chinese Medicine of the People's Republic of China, Beijing, China.,State Key Laboratory of Core Technology in Innovative Chinese Medicine, Beijing, China
| |
Collapse
|
4
|
Cheng PW, Lu PJ, Chen SR, Ho WY, Cheng WH, Hong LZ, Yeh TC, Sun GC, Wang LL, Hsiao M, Tseng CJ. Central nicotinic acetylcholine receptor involved in Ca(2+) -calmodulin-endothelial nitric oxide synthase pathway modulated hypotensive effects. Br J Pharmacol 2011; 163:1203-13. [PMID: 21091651 DOI: 10.1111/j.1476-5381.2010.01124.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Recent evidence has suggested that nicotine decreases blood pressure (BP) and heart rate (HR) in the nucleus tractus solitarii (NTS), indicating that nicotinic acetylcholine receptors (nAChRs) play an important role in BP control in the NTS. However, the signalling mechanisms involved in nAChR-mediated depressor effects in the NTS are unclear. Hence, the aim of this study was to investigate these signalling mechanisms. EXPERIMENTAL APPROACH Depressor responses to nicotine microinjected into the NTS of Wistar-Kyoto rats were elicited in the absence and presence of an antagonist of α7 nAChR, the calcium chelator ethylene glycol tetraacetic acid, a calmodulin-specific inhibitor, nitric oxide (NO) synthase (NOS) inhibitor, endothelial NOS (eNOS)-selective inhibitor or neuronal NOS (nNOS)-specific inhibitor. KEY RESULTS Microinjection of nicotine into the NTS produced a dose-dependent decrease in BP and HR, and increased nitrate levels. This depressor effect of nicotine was attenuated after pretreatment with a nAChR antagonist or blockers of the calmodulin-eNOS pathway. In contrast, N5-(1-Imino-3-butenyl)-L-ornithine (vinyl-L-NIO), nNOS-specific inhibitor, did not diminish these nicotine-mediated effects. Calmodulin was found to bind eNOS after nicotine injection into NTS. However, nicotine did not affect the eNOS phosphorylation level or eNOS upstream extracellular signal-regulated kinases (ERK)1/2 and Akt phosphorylation levels. Furthermore, pretreatment with an ERK1/2 or Akt inhibitor did not attenuate nicotine-induced depressor effects in the NTS. CONCLUSIONS AND IMPLICATIONS These results suggest that the nAChR-Ca(2+) -calmodulin-eNOS-NO signalling pathway, but not nNOS, plays a significant role in central BP regulation, and neither the ERK1/2 nor Akt signalling pathway are significantly involved in the activation of eNOS by nAChRs in the NTS.
Collapse
Affiliation(s)
- Pei-Wen Cheng
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Phosphorylated endothelial NOS Ser1177 via the PI3K/Akt pathway is depressed in the brain of stroke-prone spontaneously hypertensive rat. J Stroke Cerebrovasc Dis 2010; 20:406-12. [PMID: 20813549 DOI: 10.1016/j.jstrokecerebrovasdis.2010.01.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 01/06/2010] [Accepted: 01/24/2010] [Indexed: 11/23/2022] Open
Abstract
Stroke-prone spontaneously hypertensive rats (SHRSP) demonstrate impaired endothelium-dependent relaxation and often develop brain injuries. We investigated whether the regulatory mechanism for endothelial NOS (eNOS) phosphorylation and activation is altered in the cerebral cortex of SHRSP at a younger age. Western blot analysis revealed a low ratio of phosphor-eNOS (Ser1177) to total eNOS in SHRSP at 10 weeks of age. In addition, urinary nitric oxide metabolites (ie, nitrate and nitrite) were decreased compared with normal control WKY rats. Likewise, Akt phosphorylation (especially Ser473) was significantly reduced, with no changes in total Akt. Furthermore, the amount of the phosphatidylinositol 3-kinase (PI3K) was upstream of Akt was diminished, although attenuation of the PI3K/Akt pathway was not an effect of mTOR, another downstream target of Akt. Our findings indicate that abnormalities of the PI3K/Akt pathway in the cerebral cortex are involved in the impaired eNOS phosphorylation and activation in SHRSP.
Collapse
|
6
|
Sun C, Zubcevic J, Polson JW, Potts JT, Diez-Freire C, Zhang Q, Paton JFR, Raizada MK. Shift to an involvement of phosphatidylinositol 3-kinase in angiotensin II actions on nucleus tractus solitarii neurons of the spontaneously hypertensive rat. Circ Res 2009; 105:1248-55. [PMID: 19850939 DOI: 10.1161/circresaha.109.208926] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Central angiotensin (Ang) II inhibits baroreflex and plays an important role in the pathogenesis of hypertension. However, the underlying molecular mechanisms are still not fully understood. OBJECTIVE Our objective in the present study was to characterize the signal transduction mechanism of phosphatidylinositol 3-kinase (PI3K) involvement in Ang II-induced stimulation of central neuronal activity in cultured neurons and Ang II-induced inhibition of baroreflex in spontaneously hypertensive rats (SHR) versus WKY rats. METHODS AND RESULTS Application of Ang II to neurons produced a 42% greater increase in neuronal firing in cells from the SHR than the WKY rat. Although the Ang II-mediated increase in firing rate was abolished entirely by the protein kinase (PK)C inhibitor GF109230 in the WKY, blockade of both PKC and PI3K activity was necessary in the SHR. This was associated with an increased ability of Ang II to stimulate NADPH oxidase-reactive oxygen species (ROS)-mediated signaling involving phosphorylation of the p47phox subunit of the NADPH oxidase and was dependent on the activation of PI3K in the SHR. Inhibition of PI3K resulted in the reduction of levels of p47phox phosphorylation, NADPH oxidase activity, ROS levels, and ultimately neuronal activity in cells from the SHR but not the WKY rat. In addition, in working heart-brainstem preparations, inhibition of PKC activity in the nucleus of the solitary tract in situ abolished the Ang II-mediated depression of cardiac and sympathetic baroreceptor reflex gain in the WKY. In contrast, PKC inhibition in the nucleus of the solitary tract of SHR only partially reduced the effect of Ang II on the baroreceptor reflex gain. CONCLUSIONS These observations demonstrate that PI3K in the cardiovascular brainstem regions of the SHR may be selectively involved in Ang II-mediated signaling that includes a reduction in baroreceptor reflex function, presumably via a NADPH-ROS mediated pathway.
Collapse
Affiliation(s)
- Chengwen Sun
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32610, USA
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Zubcevic J, Waki H, Diez-Freire C, Gampel A, Raizada MK, Paton JFR. Chronic blockade of phosphatidylinositol 3-kinase in the nucleus tractus solitarii is prohypertensive in the spontaneously hypertensive rat. Hypertension 2008; 53:97-103. [PMID: 19015400 DOI: 10.1161/hypertensionaha.108.122341] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Phosphatidylinositol 3-kinase (PI3K) within brain stem neurons has been implicated in hypertension in the spontaneously hypertensive rat (SHR). Previously, we demonstrated elevated expression of PI3K subunits in rostral ventrolateral medulla and paraventricular nucleus of SHRs compared with Wistar-Kyoto rats. Here, we considered expression levels of PI3K in the nucleus tractus solitarii, a pivotal region in reflex regulation of arterial pressure, and determined its functional role for arterial pressure homeostasis in SHRs and Wistar-Kyoto rats. We found elevated mRNA levels of p110beta and p110delta catalytic PI3K subunits in the nucleus tractus solitarii of adult (12 to 14 weeks old) SHRs relative to the age-matched Wistar-Kyoto rats (fold differences relative to beta-actin: 1.7+/-0.2 versus 1.01+/-0.08 for p110beta, n=6, P<0.05; 1.62+/-0.15 versus 1.02+/-0.1 for p110delta, n=6, P<0.05). After chronic blockade of PI3K signaling in the nucleus tractus solitarii by lentiviral-mediated expression of a mutant form of p85alpha, systolic pressure increased from 175+/-3 mm Hg to 191+/-6 mm Hg (P<0.01) in SHRs but not in Wistar-Kyoto rats. In addition, heart rate increased (from 331+/-6 to 342+/-6 bpm; P<0.05) and spontaneous baroreflex gain decreased (from 0.7+/-0.07 to 0.5+/-0.04 ms/mm Hg; P<0.001) in the SHRs. Thus, PI3K signaling in the nucleus tractus solitarii of SHR restrains arterial pressure in this animal model of neurogenic hypertension.
Collapse
Affiliation(s)
- Jasenka Zubcevic
- Department of Physiology and Pharmacology, Bristol Heart Institute, School of Medical Sciences, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | | | | | | | | | | |
Collapse
|