Agmatine (CAS 2482-00-0), an amine formed by decarboxylation of L-arginine, interacts with several targets like alpha2-adrenergic, imidazoline and N-methyl-D-aspartic acid (NMDA) receptors and besides it is involved in the nitric oxide mediated effects. It has also been proposed that it possesses vasodilator effects and increases glomerular filtration rate in rats. The aim of this study was to supply evidence for the effects of agmatine in a rat model of hemorrhagic shock and explain the possible mechanisms of action. The iliac arteries and veins of Sprague-Dawley rats were catheterized under urethane anesthesia and around 2 ml/100 g blood was withdrawn within 20 min until the mean arterial blood pressure was stabilized around 25 mmHg. The rats were either pretreated with physiological saline, yohimbine (an alpha2-adrenergic receptor antagonist) or L-arginine (a nitric oxide donor) intravenously before administration of agmatine (300 microg/kg). Agmatine restored blood pressure in rats pretreated with physiological saline where all rats survived. Pretreatment with L-arginine abolished the increase in blood pressure produced by agmatine and the 1 h survival rate decreased to 67% (p < 0.01). Yohimbine pretreatment also suppressed agmatine induced restoration of blood pressure; however, the survival rate was found to be 17% for 3 min. No statistically significant effect was observed in the heart rate responses. These results may suggest that agmatine may increase survival through alpha2-adrenergic receptors and restores blood pressure through nitric oxide and adrenergic mechanisms in rats bled to hemorrhage.
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http://dx.doi.org/10.1055/s-0031-1296192 | DOI Listing |
Stem Cells Dev
January 2025
Department of Clinical Pharmacy and Pharmacy Practices, Faculty of Pharmacy, University Malaya, Kuala Lumpur, Malaysia.
Hypertension, commonly known as high blood pressure, is a significant health issue that increases the risk of cardiovascular diseases, stroke, and renal failure. This condition broadly encompasses both primary and secondary forms. Despite extensive research, the underlying mechanisms of systemic arterial hypertension-particularly primary hypertension, which has no identifiable cause and is affected by genetic and lifestyle agents-remain complex and not fully understood.
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Eye School of Chengdu, University of Traditional Medicine, Chengdu, 510100, Sichuan Province, China.
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Exp Physiol
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Centre for Healthy Ageing, Health Futures Institute, Murdoch University, Perth, Australia.
Blood flow restriction (BFR) combined with low work rate exercise can enhance muscular and cardiovascular fitness. However, whether neural mechanisms mediate these enhancements remains unknown. This study examined changes in corticospinal excitability and motor cortical inhibition following arm cycle ergometry with and without BFR.
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School of Art and Design, Beijing Forestry University, Beijing, China.
This study simulates the natural movement of plants in indoor environments to investigate whether these plants can effectively facilitate psychological, physiological, and emotional recovery from fatigue caused by short vigilance tasks. A total of 63 participants completed baseline assessments of emotional and physiological stress as well as attention and memory (including the POMS-SF, blood pressure, pulse, and Digit Span Backward). They then performed a vigilance task to induce fatigue, followed by a second measurement of stress and cognition.
View Article and Find Full Text PDFJ Gerontol A Biol Sci Med Sci
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GENUD Toledo Research Group, Faculty of Sport Sciences, University of Castilla-La Mancha, Toledo, Spain.
Mean middle cerebral artery velocity (MCAv) and the pulsatility index (PI), at rest and in response to exercise, are important markers of cerebrovascular health status in middle-aged adults, when vascular decline assumes substantial relevance. Thus, this study aimed to describe and compare the responses of MCAv and PI to incremental exercise. Two hundred and forty-eight volunteers (50-58 years, 55% women) completed a ramp test on a cycle-ergometer.
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