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Kato K, Morinaga R, Yokoyama T, Fushuku S, Wakai J, Nakamuta N, Yamamoto Y. Effects of CO 2 on time-dependent changes in cardiorespiratory functions under sustained hypoxia. Respir Physiol Neurobiol 2022; 300:103886. [PMID: 35296417 DOI: 10.1016/j.resp.2022.103886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/16/2022] [Accepted: 03/09/2022] [Indexed: 11/18/2022]
Abstract
Hypercapnia in addition to hypoxia affects the mammalian cardiorespiratory system and has been suggested to exert its effects on cardiorespiratory function by slightly different mechanisms to hypoxia. In the present study, we examined cardiorespiratory changes in urethane-anesthetized rats under hypocapnic (Hypo, 10% O2), isocapnic (Iso, 10% O2 and 4% CO2), and hypercapnic (Hyper, 10% O2 and 8% CO2) hypoxia for 2 h to clarify the effects of CO2 on sustained hypoxia-induced cardiorespiratory responses. Respiratory frequency increased the most in Hypo and tidal volume in Hyper. Minute ventilation, a product of respiratory frequency and tidal volume, increased the most in the latter group. Regarding cardiovascular variables during the hypoxic exposure period, heart rate and mean blood pressure both markedly decreased in Hypo. However, decreases in these parameters were small in Iso, and both increased over the pre-exposure level in Hyper. The present results suggest that CO2 interferes with the hypoxia-activated neural pathway via another pathway under sustained exposure to hypoxia.
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Affiliation(s)
- Kouki Kato
- Center for Laboratory Animal Science, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Ryosuke Morinaga
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, 2-1-1-1 Midorigaoka Higashi, Asahikawa, Hokkaido 078-8510, Japan
| | - Takuya Yokoyama
- Department of Anatomy (Cell Biology), Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan
| | - Seigo Fushuku
- Center for Laboratory Animal Science, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Jun Wakai
- Department of Laboratory Animal Medicine, Institute for Biomedical Sciences, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate 020-8550, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate 020-8550, Japan.
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Pandey AK, Verma S. An in-silico evaluation of dietary components for structural inhibition of SARS-Cov-2 main protease. J Biomol Struct Dyn 2020; 40:136-142. [PMID: 32811367 PMCID: PMC7484577 DOI: 10.1080/07391102.2020.1809522] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The main protease (Mpro) of SARS-CoV-2 is responsible for the cleavage of viral replicase polyproteins 1a and 1ab into their mature form and is highly specific and exclusive in its activity. Many studies have targeted this enzyme by small molecule inhibitors to develop therapeutics against the highly infectious disease Covid-19. Our diet contains many natural antioxidants which along with providing support for proper growth and functioning of the body, pose additional health benefits. Present in-silico analysis depicted that natural antioxidants like sesamin, ellagic acid, capsaisin, and epicatechin along with galangin, exhibited significant binding at the catalytic site of the Mpro enzyme. They interacted with excellent efficiency with the chief active site residue Cys145 and thus seem to possess the remarkable potential to act as drug candidates for the treatment of Covid-19. Such dietary compounds can be easily administered orally with least toxicity related concern and thus yell for urgent exhaustive research to develop into efficient therapies. Communicated by Ramaswamy H. Sarma
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Affiliation(s)
- Anand Kumar Pandey
- Department of Biotechnology Engineering, Institute of Engineering and Technology, Bundelkhand University, Jhansi, India
| | - Shalja Verma
- Department of Biotechnology Engineering, Institute of Engineering and Technology, Bundelkhand University, Jhansi, India.,Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi, India
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Garami A, Shimansky YP, Rumbus Z, Vizin RCL, Farkas N, Hegyi J, Szakacs Z, Solymar M, Csenkey A, Chiche DA, Kapil R, Kyle DJ, Van Horn WD, Hegyi P, Romanovsky AA. Hyperthermia induced by transient receptor potential vanilloid-1 (TRPV1) antagonists in human clinical trials: Insights from mathematical modeling and meta-analysis. Pharmacol Ther 2020; 208:107474. [PMID: 31926897 DOI: 10.1016/j.pharmthera.2020.107474] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 12/23/2019] [Indexed: 02/06/2023]
Abstract
Antagonists of the transient receptor potential vanilloid-1 (TRPV1) channel alter body temperature (Tb) in laboratory animals and humans: most cause hyperthermia; some produce hypothermia; and yet others have no effect. TRPV1 can be activated by capsaicin (CAP), protons (low pH), and heat. First-generation (polymodal) TRPV1 antagonists potently block all three TRPV1 activation modes. Second-generation (mode-selective) TRPV1 antagonists potently block channel activation by CAP, but exert different effects (e.g., potentiation, no effect, or low-potency inhibition) in the proton mode, heat mode, or both. Based on our earlier studies in rats, only one mode of TRPV1 activation - by protons - is involved in thermoregulatory responses to TRPV1 antagonists. In rats, compounds that potently block, potentiate, or have no effect on proton activation cause hyperthermia, hypothermia, or no effect on Tb, respectively. A Tb response occurs when a TRPV1 antagonist blocks (in case of hyperthermia) or potentiates (hypothermia) the tonic TRPV1 activation by protons somewhere in the trunk, perhaps in muscles, and - via the acido-antithermogenic and acido-antivasoconstrictor reflexes - modulates thermogenesis and skin vasoconstriction. In this work, we used a mathematical model to analyze Tb data from human clinical trials of TRPV1 antagonists. The analysis suggests that, in humans, the hyperthermic effect depends on the antagonist's potency to block TRPV1 activation not only by protons, but also by heat, while the CAP activation mode is uninvolved. Whereas in rats TRPV1 drives thermoeffectors by mediating pH signals from the trunk, but not Tb signals, our analysis suggests that TRPV1 mediates both pH and thermal signals driving thermoregulation in humans. Hence, in humans (but not in rats), TRPV1 is likely to serve as a thermosensor of the thermoregulation system. We also conducted a meta-analysis of Tb data from human trials and found that polymodal TRPV1 antagonists (ABT-102, AZD1386, and V116517) increase Tb, whereas the mode-selective blocker NEO6860 does not. Several strategies of harnessing the thermoregulatory effects of TRPV1 antagonists in humans are discussed.
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Affiliation(s)
- Andras Garami
- Department of Thermophysiology, Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary.
| | - Yury P Shimansky
- Department of Neurobiology, Barrow Neurological Institute, Dignity Health, Phoenix, AZ, USA
| | - Zoltan Rumbus
- Department of Thermophysiology, Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Robson C L Vizin
- Thermoregulation and Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Dignity Health, Phoenix, AZ, USA
| | - Nelli Farkas
- Institute for Translational Medicine, Medical School and Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Judit Hegyi
- Institute for Translational Medicine, Medical School and Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Zsolt Szakacs
- Institute for Translational Medicine, Medical School and Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Margit Solymar
- Department of Thermophysiology, Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Alexandra Csenkey
- Department of Thermophysiology, Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | | | | | | | - Wade D Van Horn
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | - Peter Hegyi
- Institute for Translational Medicine, Medical School and Szentagothai Research Centre, University of Pecs, Pecs, Hungary; Department of Translational Medicine, First Department of Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Andrej A Romanovsky
- Thermoregulation and Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Dignity Health, Phoenix, AZ, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, USA; Zharko Pharma Inc., Olympia, WA, USA.
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