1
|
Mori A, Takei T, Suzuki N, Sakamoto K, Morita M, Nakagawa S, Nakahara T, Ishii K. L-Citrulline ameliorates the attenuation of acetylcholine-induced vasodilation of retinal arterioles in diabetic rats. Heliyon 2021; 7:e06532. [PMID: 33842702 PMCID: PMC8020426 DOI: 10.1016/j.heliyon.2021.e06532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/29/2020] [Accepted: 03/12/2021] [Indexed: 02/01/2023] Open
Abstract
In our previous study, we found that the vasodilation of retinal arterioles induced by acetylcholine and BMS-191011, a large-conductance Ca2+-activated K+ (BKCa) channel opener, were diminished in diabetic rats. Currently, few agents ameliorate the impaired vasodilator responses of retinal blood vessels. Our recent finding that the intravenous infusion of L-citrulline dilated retinal arterioles, suggests that L-citrulline could be a potential therapeutic agent for circulatory disorders of the retina. In this study, we determined the effect of an oral L-citrulline treatment on impaired acetylcholine- and BMS-191011-induced vasodilation in the retinal arterioles of diabetic rats. To induce diabetes, rats were administered an intravenous dose of streptozotocin (65 mg/kg) and a 5% D-glucose solution as drinking water. The L-citrulline (2 g/kg/day) and L-arginine (2 g/kg/day) treatments commenced either 15 days before or just after the streptozotocin injection and continued throughout the experimental period. A 29-day treatment with L-citrulline, but not L-arginine, significantly ameliorated the impaired acetylcholine- and BMS-191011-induced retinal vasodilation in diabetic rats without affecting their plasma glucose levels. The 2-week L-citrulline treatment tended to ameliorate the dysfunction of the acetylcholine-induced retinal vasodilation in diabetic rats. In conclusion, these results showed that the retinal blood vessel dysfunction induced by diabetes mellitus could be prevented by the long-term administration of L-citrulline and suggest that the latter could play a potentially prophylactic role in diabetic retinopathy.
Collapse
Affiliation(s)
- Asami Mori
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
- Corresponding author.
| | - Toshiaki Takei
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Namiko Suzuki
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Kenji Sakamoto
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Masahiko Morita
- Research & Innovation Center, KYOWA HAKKO BIO CO., LTD, 2 Miyukigaoka, Tsukuba-shi, Ibaraki, 305-0841, Japan
| | - Satoshi Nakagawa
- Research & Innovation Center, KYOWA HAKKO BIO CO., LTD, 2 Miyukigaoka, Tsukuba-shi, Ibaraki, 305-0841, Japan
| | - Tsutomu Nakahara
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Kunio Ishii
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| |
Collapse
|
2
|
Abstract
Airway smooth muscle contributes to both contractility and inflammation in the pathophysiology of asthma and COPD. Airway smooth muscle cells can change the degree of a variety of functions, including contraction, proliferation, migration, and the secretion of inflammatory mediators (phenotype plasticity). Airflow limitation, airway hyperresponsiveness, β2-adrenergic desensitization, and airway remodeling, which are fundamental characteristic features of these diseases, are caused by phenotype changes in airway smooth muscle cells. Alterations between contractile and hyper-contractile, synthetic/proliferative phenotypes result from Ca2+ dynamics and Ca2+ sensitization. Modulation of Ca2+ dynamics through the large-conductance Ca2+-activated K+ channel/L-type voltage-dependent Ca2+ channel linkage and of Ca2+ sensitization through the RhoA/Rho-kinase pathway contributes not only to alterations in the contractile phenotype involved in airflow limitation, airway hyperresponsiveness, and β2-adrenergic desensitization but also to alteration of the synthetic/proliferative phenotype involved in airway remodeling. These Ca2+ signal pathways are also associated with synergistic effects due to allosteric modulation between β2-adrenergic agonists and muscarinic antagonists. Therefore, airway smooth muscle may be a target tissue in the therapy for these diseases. Moreover, the phenotype changing in airway smooth muscle cells with focuses on Ca2+ signaling may provide novel strategies for research and development of effective remedies against both bronchoconstriction and inflammation.
Collapse
|
3
|
Mori A, Higashi K, Wakao S, Sakamoto K, Ishii K, Nakahara T. Probucol prevents the attenuation of β 2-adrenoceptor-mediated vasodilation of retinal arterioles in diabetic rats. Naunyn Schmiedebergs Arch Pharmacol 2017; 390:1247-53. [PMID: 28913547 DOI: 10.1007/s00210-017-1423-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 09/04/2017] [Indexed: 10/18/2022]
Abstract
Probucol is an antihyperlipidemic drug with potent antioxidant properties. Oxidative stress plays an important role in the pathogenesis of diabetic retinopathy. In this study, we aimed to investigate the protective effects of probucol against diabetes-induced retinal vascular dysfunction in a rat model of diabetes. Diabetes was induced by a combination of streptozotocin treatment and D-glucose feeding, and retinal vasodilator responses were assessed by measuring the diameter of retinal arterioles. The vasodilator effect of salbutamol, a β2-adrenoceptor agonist, on retinal arterioles was significantly diminished 2 weeks after the induction of diabetes. In non-diabetic rats, vasodilator responses to salbutamol were significantly reduced after an intravitreal injection of iberiotoxin, a blocker of large-conductance KCa (BKCa) channels. However, this effect was not observed in diabetic rats. Probucol had no significant effect on salbutamol-induced changes in diameter of retinal arterioles in non-diabetic rats, whereas it could prevent the attenuation of retinal vasodilator response to salbutamol in diabetic rats. These results suggest that the reduced function of BKCa channels is involved in the attenuation of β2-adrenoceptor-mediated retinal vasodilation in diabetic rats. Probucol preserves the BKCa channel function in retinal arterioles under diabetic conditions; therefore, it may show beneficial effects on diabetic retinopathy by preventing or slowing the impairment of the retinal circulation in patients with diabetes mellitus.
Collapse
|
4
|
Bo L, Jiang L, Zhou A, Wu C, Li J, Gao Q, Zhang P, Lv J, Li N, Gu X, Zhu Z, Mao C, Xu Z. Maternal high-salt diets affected pressor responses and microvasoconstriction via PKC/BK channel signaling pathways in rat offspring. Mol Nutr Food Res 2015; 59:1190-9. [PMID: 25737272 DOI: 10.1002/mnfr.201400841] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/20/2015] [Accepted: 02/17/2015] [Indexed: 02/03/2023]
Abstract
SCOPE High-salt (HS) intake is linked to hypertension, and prenatal exposure to maternal HS diets may have long-term impact on cardiovascular systems. The relationship between HS diets and cardiovascular disease has received extensive attention. This study determined pressor responses and microvessel functions in the adult offspring rats exposed to prenatal HS. METHODS AND RESULTS The offspring of 5-month old as young adults in rats were used. Blood pressure, vascular tone, intracellular Ca(2+), and BK channels in mesenteric arteries were measured in the offspring. Phenylephrine (Phe)-induced pressor responses were significantly higher in the prenatal HS offspring. Vessel tension and intracellular Ca(2+) concentrations associated with Phe-induced pressor responses were increased in the mesenteric arteries of the HS offspring. PKC α- and δ-isoforms were upregulated in mesenteric arteries of the HS offspring. The enhanced Phe-mediated vascular activity was linked to the altered PKC-modulated BK channel functions. CONCLUSION The results suggested that prenatal exposure to HS altered microvascular activity probably via changes in PKC/BK signaling pathways, which may lead to increased risks of hypertension in the offspring.
Collapse
Affiliation(s)
- Le Bo
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Lin Jiang
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Anwen Zhou
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Chonglong Wu
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Jiayue Li
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Qinqin Gao
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Pengjie Zhang
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Juanxiu Lv
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Na Li
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Xiuxia Gu
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Zhoufeng Zhu
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Caiping Mao
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China
| | - Zhice Xu
- Institute for Fetology & Reproductive Medicine Center, First Hospital of Soochow University, Suzhou, P. R. China.,Center for Prenatal Biology, Loma Linda University, CA, USA
| |
Collapse
|