AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY, INTEGRATIVE AND COMPARISON PHYSIOLOGY 发表了原创研究，阐明了从分子到人类的各个层面的生理机制的正常或异常调节和整合，包括临床研究。重点领域包括对转基因动物的监管；模式生物；发育和组织可塑性；循环和高血压的神经体液控制；局部循环控制；心脏和肾脏整合；口渴和容量，电解质稳态；葡萄糖稳态和能量平衡；食欲和肥胖；炎症和细胞因子；妊娠-分娩-哺乳的综合生理学；以及对运动和环境压力的体温调节和适应。

The American Journal of Physiology - Regulatory Integrative and Comparative Physiology publishes original research that elucidates the normal and abnormal regulation and integration of physiological mechanisms across various levels, from molecules to humans, including clinical studies. Key areas of focus include the regulation of transgenic animals, model organisms, developmental and tissue plasticity, neurohumoral control of circulation and hypertension, local circulation control, integration of cardiac and renal functions, thirst and volume, electrolyte homeostasis, glucose homeostasis and energy balance, appetite and obesity, inflammation and cytokines, the integrative physiology of pregnancy, childbirth, and lactation, as well as thermoregulation and adaptation to exercise and environmental stress.

《American Journal of Physiology - Regulatory Integrative and Comparative Physiology》发表原创研究，阐明从分子到人类各个层面的生理机制的正常与异常调节和整合，包括临床研究。重点领域包括转基因动物的调控、模式生物、发育与组织可塑性、循环与高血压的神经体液控制、局部循环控制、心脏与肾脏的整合、口渴与容量、电解质稳态、葡萄糖稳态与能量平衡、食欲与肥胖、炎症与细胞因子、妊娠-分娩-哺乳的综合生理学，以及对运动与环境压力的体温调节与适应。

American Journal of Physiology - Regulatory Integrative and Comparative Physiology

We tested the hypothesis that the asymptote of the hyperbolic relationship between work rate and time to exhaustion during muscular exercise, the “critical power” (CP), represents the highest constant work rate that can be sustained without a progressive loss of homeostasis [as assessed using 31 P magnetic resonance spectroscopy (MRS) measurements of muscle metabolites]. Six healthy male subjects initially completed single-leg knee-extension exercise at three to four different constant work rates to the limit of tolerance (range 3–18 min) for estimation of the CP (mean ± SD, 20 ± 2 W). Subsequently, the subjects exercised at work rates 10% below CP (&lt;CP) for 20 min and 10% above CP (&gt;CP) for as long as possible, while the metabolic responses in the contracting quadriceps muscle, i.e., phosphorylcreatine concentration ([PCr]), P i concentration ([P i ]), and pH, were estimated using 31 P-MRS. All subjects completed 20 min of &lt;CP exercise without duress, whereas the limit of tolerance during &gt;CP exercise was 14.7 ± 7.1 min. During &lt;CP exercise, stable values for [PCr], [P i ], and pH were attained within 3 min after the onset of exercise, and there were no further significant changes in these variables (end-exercise values = 68 ± 11% of baseline [PCr], 314 ± 216% of baseline [P i ], and pH 7.01 ± 0.03). During &gt;CP exercise, however, [PCr] continued to fall to the point of exhaustion and [P i ] and pH changed precipitously to values that are typically observed at the termination of high-intensity exhaustive exercise (end-exercise values = 26 ± 16% of baseline [PCr], 564 ± 167% of baseline [P i ], and pH 6.87 ± 0.10, all P &lt; 0.05 vs. &lt;CP exercise). These data support the hypothesis that the CP represents the highest constant work rate that can be sustained without a progressive depletion of muscle high-energy phosphates and a rapid accumulation of metabolites (i.e., H + concentration and [P i ]), which have been associated with the fatigue process.

Andrew M Jones

Daryl P Wilkerson

Fred DiMenna

Jonathan Fulford

David C Poole

AJP Regulatory Integrative and Comparative Physiology

Muscle metabolic responses to exercise above and below the “critical power” assessed using31P-MRS

使用31P-MRS评估高于和低于“临界功率”运动时的肌肉代谢反应

Glucagon-like peptide 1 receptors (GLP-1R) are expressed in multiple tissues and activation results in metabolic benefits including enhanced insulin secretion, slowed gastric emptying, suppressed food intake, and improved hepatic steatosis. Limited and inconclusive knowledge exists regarding whether the effects of chronic exposure to a GLP-1R agonist are solely mediated via this receptor. Therefore, we examined 3-mo dosing of exenatide in mice lacking a functional GLP-1R (Glp1r(-/-)). Exenatide (30 nmol · kg(-1) · day(-1)) was infused subcutaneously for 12 wk in Glp1r(-/-) and wild-type (Glp1r(+/+)) control mice fed a high-fat diet. Glycated hemoglobin A1c (HbA1c), plasma glucose, insulin, amylase, lipase, alanine aminotransferase (ALT), aspartate aminotransferase (AST), body weight, food intake, terminal hepatic lipid content (HLC), and plasma exenatide levels were measured. At the end of the study, oral glucose tolerance test (OGTT) and rate of gastric emptying were assessed. Exenatide produced no significant changes in Glp1r(-/-) mice at study end. In contrast, exenatide decreased body weight, food intake, and glucose in Glp1r(+/+) mice. When compared with vehicle, exenatide reduced insulin, OGTT glucose AUC0-2h, ALT, and HLC in Glp1r(+/+) mice. Exenatide had no effect on plasma amylase or lipase levels. Exenatide concentrations were approximately eightfold higher in Glp1r(-/-) versus Glp1r(+/+) mice after 12 wk of infusion, whereas renal function was similar. These data support the concept that exenatide requires a functional GLP-1R to exert chronic metabolic effects in mice, and that novel "GLP-1" receptors may not substantially contribute to these changes. Differential exenatide plasma levels in Glp1r(+/+) versus Glp1r(-/-) mice suggest that GLP-1R may play an important role in plasma clearance of exenatide and potentially other GLP-1-related peptides.

Krystyna Tatarkiewicz

Emmanuel J. Sablan

Clara J. Polizzi

Christiane Villescaz

David G. Parkes

Long-term metabolic benefits of exenatide in mice are mediated solely via the known glucagon-like peptide 1 receptor

长期使用艾塞那肽对小鼠的代谢益处完全通过已知的胰高血糖素样肽-1受体介导

Systemic or hindbrain administration of MK-801, a noncompetitive N-methyl-d-aspartate receptor antagonist, increases meal size. To examine whether MK-801 enhances intake by increasing gastric emptying, we administered MK-801 (2.0 μg/3.0 μl) into the fourth ventricle [intracerebroventricular (ICV)] and measured feeding and gastric emptying of 5-ml NaCl or 15% sucrose loads. In a parallel experiment, we examined food intake and gastric emptying following intraperitoneal (IP) injection of MK-801 (100 μg/kg). MK-801, either IP or ICV, increased 30-min sucrose intake compared with control (12.3 ± 0.7 vs. 9.8 ± 0.5 and 16.6 ± 2.0 vs. 10.7 ± 0.7 ml, for IP and ICV administration, respectively). Also, IP MK-801 increased 5-min gastric emptying of NaCl (4.13 ± 0.1 ml emptied) and sucrose (3.11 ± 0.1 ml emptied) compared with control (3.75 ± 0.2 and 2.28 ± 0.1 ml emptied for NaCl and sucrose loads, respectively). In contrast, ICV MK-801 did not alter NaCl emptying (3.82 ± 0.1 ml emptied) compared with control (3.82 ± 0.3 ml emptied) and actually reduced gastric emptying of sucrose (2.1 ± 0.2 and 2.94 ± 0.1 ml emptied, for MK and vehicle, respectively). These data confirm previous results that systemic as well as hindbrain injection of MK-801 increases food intake. However, because ICV MK-801 failed to increase gastric emptying, these results indicate that MK-801 increases food intake through mechanisms independent of altered gastric emptying.

M Covasa

Chun-Yi Hung

R C Ritter

G A Burns

Intracerebroventricular administration of MK-801 increases food intake through mechanisms independent of gastric emptying

脑室内注射MK-801通过与胃排空无关的机制增加摄食量

Interactions between heart rate (HR) and the Frank-Starling mechanism in augmenting cardiac output (CO) during acute volume loading were studied in dogs under varying conditions. In normal conscious dogs with low HRs of 70--90 beats/min, end-diastolic diameter (EDD) was maximal and CO was increased reflexly by cardioacceleration. By contrast, anesthetized open-chest dogs with high HRs ranging from 140 to 160 beats/min, responded with bradycardia and CO was adjusted solely by increasing stroke volume (SV). In anesthetized open-chest dogs with low HRs, EDD was less than maximal and increases in both HR and SV contributed to augment CO. These data show that both the cardioacceleration reflex and the Frank-Starling mechanism are important determinants of the cardiac response to elevated preload. Although the relative contribution of each control mechanism varies with initial conditions, their interplay extends the range of cardioregulation beyond that attainable by either loop operating alone.

G. E. Barnes

B. C. Chevis

H. J. Granger

Regulation of cardiac output during rapid volume loading

快速容量负荷期间心输出量的调节

Nocturnal oxygen enrichment improves sleep at high-altitude but may impair acclimatization. PURPOSE: Determine if nocturnal oxygen enrichment impacts acclimatization. METHODS: A 7-day acclimatization protocol occurred at a field-based research site between 0-4200m. Participants were housed at 2800m and slept with (O 2 +, 32.3±2.5% O 2 ) or without (O 2 -, 20.8±0.1% O 2 ) nocturnal oxygen enrichment. Resting and steady-state cycling (5-min, 1.75 W·kg -1 ) tests occurred on Day 0 (0m) and Days 1, 4, and 7 (2800m). Sleep, &lt;em&gt;vastus lateralis&lt;/em&gt; muscle oxygenation (oxygenated hemoglobin [O 2 Hb], deoxygenated hemoglobin [HHb]), arterial blood oxygen saturation (SPO 2 ), heart rate (HR), and expired gases were measured. Five daily hikes from 2800-4200m were also completed. RESULTS: Sleep was longer (p=0.028) and overnight SPO 2 higher (p&lt;0.001) in the O 2 + (452±63 min, 96±1%) than the O 2 - group (427±63 min, 91±2%). The O 2 + and O 2 - groups did not differ at rest in ∆O 2 Hb (-1.47±0.99, -1.46±1.30 A.U., p=0.901), ∆HHb (0.78±0.84, 0.51±0.96 A.U., p=0.202), SPO 2 (93±3, 93±3%, p=1.000), HR (59±6, 64±13 beats·minute -1 , p=0.229), respiratory exchange ratio (RER, 0.81±0.07, 0.79±0.06, p=0.274), and ventilation BTPS (10.56±2.12, 10.80±1.96 L·minute -1 , p=0.717). The O 2 + and O 2 - groups also did not differ while cycling in ∆O 2 Hb (-2.96±3.03, -1.70±3.46 A.U., p=0.278), ∆HHb (7.59±4.65, 6.34±3.21 A.U., p=0.451), SPO 2 (90±6, 89±6%, p=0.875), HR (113±10, 118±16 beats·minute -1 , p=0.408), RER (0.89±0.06, 0.89±0.07, p=0.756), and ventilation BTPS (54.00±15.42, 60.18±18.42 L·minute -1 , p=0.371). SPO 2 while cycling returned towards Day 0 (0m) values by Day 7 (2800m) in both groups (p&lt;0.001) indicating short-term acclimatization. CONCLUSION: Nocturnal oxygen enrichment improves sleep but does not impair short-term acclimatization when completing daily prolonged exercise.

Alejandro M. Rosales

Walter S. Hailes

Christopher W. Collins

Mark L. McGlynn

Brent C. Ruby

Dustin R. Slivka

IMPACT OF NOCTURNAL OXYGEN ENRICHMENT ON HIGH-ALTITUDE ACCLIMATIZATION

夜间氧气富集对高原适应的影响

Preterm birth increases the risk of cardiometabolic disease in adulthood. Infants born during the second trimester of pregnancy, a critical period of hypothalamic development, are at risk of sodium (Na) depletion due to renal immaturity and large urine Na losses. We previously demonstrated in male mice that Na restriction during the equivalent mouse hypothalamic development period (PD21-PD42) programs long-term changes in energy balance via increased thermogenic sympathetic nervous activity. We therefore hypothesized that early-life Na restriction programs changes in cardiovascular control via altered autonomic activity. C57BL/6J male mice were supplied a low (0.04%) Na or supplemented (0.30%) Na diet from PD21-PD42, before return to standard (0.15%) Na diet. Hemodynamic and autonomic functions were assessed by radiotelemetry and acute administration of autonomic antagonists before and after all animals were switched to a high Na diet (HSD; 1% Na) at 12 weeks of age. Mice were additionally treated with the angiotensin II type 1 receptor (AT

Alisha A. Ziegler

Samuel B. R. Lawton

Eva M. Fekete

Daniel T. Brozoski

Valerie A. Wagner

Connie C. Grobe

Curt D. Sigmund

Pablo Nakagawa

Justin L. Grobe

Jeffrey L. Segar

Early-life sodium restriction programs autonomic dysfunction and salt sensitivity in male C57BL/6J mice

早期限制钠摄入导致雄性C57BL/6J小鼠自主神经功能障碍和盐敏感性

The cause and consequences of inosine monophosphate (IMP) formation when ATP declines during muscular contractions in vivo are not fully understood. The purpose of this study was to examine the role of IMP formation in the maintenance of the Gibbs free energy for ATP hydrolysis (∆G ATP ) during dynamic contractions of increasing workload, and the implications of ATP loss in vivo. Eight males (27.5, 25-35yr, median, range) completed an 8-minute incremental protocol (2-minute stages of isotonic knee extensions (0.5Hz)) in a 3-Tesla magnetic resonance (MR) system. Phosphorus MR spectra were obtained from the knee extensor muscles at rest and during contractions and recovery. Although the ATP demand during contractions was met primarily by oxidative phosphorylation, [ATP] decreased from 8.2 mM to 7.5 (range 6.4-8.0) mM and [IMP] increased from 0 mM to 0.6 (0.1-1.7) mM. Modeling showed that, in the absence of IMP formation, excess ADP would result in a less favorable ∆G ATP (p&lt;0.001). Neither [ATP] nor [IMP] had returned to baseline following 10 minutes of recovery (p&lt;0.001). Notably, ∆[ATP] was linearly related to the post-contraction reduction in muscle oxidative capacity (r=0.74, p=0.037). Our results highlight the importance of IMP formation in preserving cellular energy status by avoiding increases in ADP above that necessary to stimulate energy production pathways. However, the consequence of IMP formation was an incomplete recovery of [ATP], which in turn was related to decreased muscle oxidative capacity following contractions. These results likely have implications for the capacity to generate adequate energy during repeated bouts of muscular work.

Zoe H. Smith

Christopher M.T. Hayden

Kate L Hayes

Jane A. Kent

Skeletal Muscle Inosine Monophosphate Formation Preserves ∆GATP During Incremental Step Contractions in Vivo

骨骼肌肌苷单磷酸形成在体内递增阶梯式收缩期间维持ΔGATP

The local sweat rate (LSR) response to intradermal electrical stimulation generates a sigmodal stimulus-response curve with a peak sweat rate generated during a 30 s period of continuous stimuli at a frequency of 16 to 32 Hz. However, the in vivo firing pattern of the sudomotor nerve resembles more of a bursting pattern. We tested the hypothesis that a bursting pattern during intradermal electrical stimulation would result in a greater sweating response than the regular continuous stimulus pattern. 15 subjects were studied in a temperature-controlled room at 27.6 ± 0.2 {degree sign}C. The LSR was measured with a miniature sweat capsule with guide sleeves for holding the intradermal stimulating electrodes. The nine continuous stimulus frequencies (0.2, 1, 2, 4, 8, 12, 16, 32, and 64 Hz) were compared to a bursting pattern with a similar total number of stimuli. The sweating response was determined as the area under the LSR-time curve. Peak LSR was slightly higher for the continuous stimuli (0.396 ± 0.242 mg • min -1 • cm -2 ,p = 0.023) than for the bursting stimuli (0.356 ± 0.244 mg • min -1 • cm -2 ). The sigmoidal shaped stimulus response curves, however, were significantly different (p = 0.0007). The EC 50 (p = 0.0029) was higher during continuous stimulation and the Hill slope was lower (p&lt;0.0001) during bursting stimuli. These data do not support the concept that a bursting stimulus pattern during intradermal electrical stimulation evokes a greater LSR.

Gary W. Mack

Kaylee M. Bahr

Christian J. McEwan

Carson J. Price

Ashton J. Renfro

Intradermal electrical stimulation of sudomotor nerves and local sweat rate.

汗腺神经皮内电刺激与局部出汗率。

The assessment of adrenergic modulation of sweating as assessed via pharmacologic administration of α- and β-adrenergic receptor blockers during exercise has yielded mixed findings. However, the underlying mechanisms for this disparity remains unresolved. We investigated the effects of separate and combined blockade of α- and β-adrenergic receptors on forearm sweating induced by a 30-min moderate-intensity exercise bout (n=17, protocol 1) and the administration of adrenergic agonists epinephrine and norepinephrine (n=16, protocol 2) in the heat. Adrenergic receptor blockade was induced via the separate and combined iontophoretic administration of terazosin (α-adrenergic receptor antagonist) and propranolol (β-adrenergic receptor antagonist) on forearm skin. Bretylium, a noradrenergic sympathetic nerve inhibitor was also administered separately in protocol 1. In protocol 1, relative to the separate administration of propranolol, terazosin alone or in combination with propranolol attenuated exercise sweating to a similar extent (both P£0.037), although the effect was reduced relative to that observed with bretylium treatment ( P&lt;0.001). In protocol 2, administration of propranolol increased norepinephrine- ( P=0.029) but not epinephrine-induced sweat rate. The combined administration of terazosin reversed this response, attenuating sweating ( P&lt;0.001) to a greater extent than terazosin treatment alone ( P=0.030). Altogether, we showed that while β-adrenergic receptors may interact with α-adrenergic receptors pharmacologically, it does not appear to modulate exercise-induced sweating on the forearm. Further, α- but not β-adrenergic receptors independently modulate the regulation of forearm sweating during exercise in the heat. Finally, the bretylium-induced reduction in forearm sweat rate during exercise likely occurs independently of α- and β-adrenergic receptors.

Tatsuro Amano

Naoto Fujii

Glen P. Kenny

Toby Mündel

Yoshimitsu Inoue

Shotaro Yokoyama

Narihiko Kondo

Separate and combined blockades of α- and β-adrenergic receptors in forearm sweating induced by adrenergic agents and exercise in the heat in young adults

青年成人中由肾上腺素能药物和热环境下运动引起的上肢出汗的α和β肾上腺素能受体单独及联合阻断作用

Mariana R. Lauar

Nayara Pestana-Oliveira

John P. Collister

Lucy Vulchanova

Louise C. Evans

John W. Osborn

The Organum Vasculosum of the Lamina Terminalis Contributes to Neurohumoral Mechanisms of Renal Vascular Hypertension

终板血管器参与肾血管性高血压的神经体液机制

Abbreviation	Am. J. Physiol. Integr. Comp. Physiol.
Journal Impact	2.26
Quartiles(Global)	PHYSIOLOGY(Q3)

ISSN	0363-6119, 1522-1490
h-index	194

Publication Information	Publisher: American Physiological Society，Publishing cycle: Monthly，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 1977，Proportion of original research papers: 92.03%，Self Citation Rate:4.50%， Gold OA Rate: 5.44%
Average review cycle	网友分享经验：平均2月
Average recruitment ratio	网友分享经验：约25%

American Journal of Physiology - Regulatory Integrative and Comparative Physiology

Journal Citation Format

A journal article with 1 author

A journal article with 2 authors

A journal article with 3 authors

A journal article with 5 or more authors

Books Citation Format

Thesis Citation Format

Web sites Citation Format

Patent Citation Format

Staying up late manually editing references? ivySCI automatically matches journals and helps you generate references with a single click.

Share Submission Experience

Muscle metabolic responses to exercise above and below the “critical power” assessed using³¹P-MRS