Experimental physiology
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Experimental physiology · Feb 2017
Elevated skin and core temperatures both contribute to reductions in tolerance to a simulated haemorrhagic challenge.
What is the central question of this study? Combined increases in skin and core temperatures reduce tolerance to a simulated haemorrhagic challenge. The aim of this study was to examine the separate and combined influences of increased skin and core temperatures upon tolerance to a simulated haemorrhagic challenge. What is the main finding and its importance? Skin and core temperatures increase during many occupational settings, including military procedures, in hot environments. ⋯ The lowest LBNP tolerance was observed during combined skin and core hyperthermia (257 ± 106 mmHg min; P < 0.05 relative to all other trials). These data indicate that elevated skin temperature, as well as elevated core temperature, can both contribute to reductions in LBNP tolerance in heat-stressed individuals. However, heat stress-induced reductions in LBNP tolerance are greatest in conditions when both skin and core temperatures are elevated.
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Experimental physiology · Feb 2017
Butyrate stimulates adipose lipolysis and mitochondrial oxidative phosphorylation through histone hyperacetylation-associated β3 -adrenergic receptor activation in high-fat diet-induced obese mice.
What is the central question of this study? Butyrate can prevent diet-induced obesity through increasing energy expenditure. However, it is unclear whether β3 -adrenergic receptors (ARβ3) mediate butyrate-induced adipose lipolysis. What is the main finding and its importance? Short-term oral administration of sodium butyrate is effective in alleviating diet-induced obesity through activation of ARβ3-mediated lipolysis in white adipose tissue. ⋯ The G protein-coupled receptor 43 and p-CREB (Ser133) were significantly stimulated by SB. In addition, an active transcription marker, H3K9Ac, was significantly enriched on the promoter of the ARβ3 gene. Our results indicate that short-term oral administration of SB is effective in alleviating diet-induced obesity through activation of the ARβ3-mediated lipolysis in the epididymal white adipose tissue.
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Experimental physiology · Feb 2017
Effects of early and delayed initiation of exercise training on cardiac and haemodynamic function after spinal cord injury.
What is the central question of this study? How does early versus delayed initiation of passive hindlimb cycling, as well as detraining, affect cardiac function and blood pressure control in a rodent model of spinal cord injury? What is the main finding and its importance? Early or delayed initiation of hindlimb cycling improves cardiac and haemodynamic function in spinal cord injury, although the benefits of early administration are more pronounced. We also demonstrate the need for exercise to be maintained, because detraining rapidly reverses the cardiac and haemodynamic benefits. Spinal cord injury (SCI) reduces physical activity and alters descending supraspinal cardiovascular control, predisposing this population to early onset of cardiovascular disease. ⋯ Between weeks 7 and 9 post-SCI, the no PHLC/delayed PHLC rats exhibited fewer spontaneous AD events than the early PHLC/detraining rats (P < 0.01). We show, for the first time, that delayed exercise promotes similar improvements in cardiac and haemodynamic function to those observed with early initiation. Furthermore, exercise needs to be maintained, because detraining reduces these cardiohaemodynamic benefits.