AJP: Regulatory, Integrative and Comparative Physiology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Bradykinin does not acutely sensitize the reflex pressor response during hindlimb skeletal muscle stretch in decerebrate rats
Hindlimb skeletal muscle stretch (i.e., selective activation of the muscle mechanoreflex) in decerebrate rats evokes reflex increases in blood pressure and sympathetic nerve activity. Bradykinin has been found to sensitize mechanogated channels through a bradykinin B2 receptor-dependent mechanism. Moreover, bradykinin B2 receptor expression on sensory neurons is increased following chronic femoral artery ligation in the rat (a model of simulated peripheral artery disease). We tested the hypothesis that injection of bradykinin into the arterial supply of a hindlimb in decerebrate, unanesthetized rats would acutely augment (...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 9, 2017 Category: Physiology Authors: Rollins, K. S., Smith, J. R., Esau, P. J., Kempf, E. A., Hopkins, T. D., Copp, S. W. Tags: Research Article Source Type: research

Detection of maltodextrin and its discrimination from sucrose are independent of the T1R2 + T1R3 heterodimer
Maltodextrins, such as Maltrin and Polycose, are glucose polymer mixtures of varying chain lengths that are palatable to rodents. Although glucose and other sugars activate the T1R2 + T1R3 "sweet" taste receptor, recent evidence from T1R2- or T1R3-knockout (KO) mice suggests that maltodextrins, despite their glucose polymer composition, activate a separate receptor mechanism to generate a taste percept qualitatively distinguishable from that of sweeteners. However, explicit discrimination of maltodextrins from prototypical sweeteners has not yet been psychophysically tested in any murine model. Therefore, mice lacking T1R2...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 9, 2017 Category: Physiology Authors: Smith, K. R., Spector, A. C. Tags: Research Article Source Type: research

Functional and neurochemical characterization of angiotensin type 1A receptor-expressing neurons in the nucleus of the solitary tract of the mouse
Angiotensin II acts via two main receptors within the central nervous system, with the type 1A receptor (AT1AR) most widely expressed in adult neurons. Activation of the AT1R in the nucleus of the solitary tract (NTS), the principal nucleus receiving central synapses of viscerosensory afferents, modulates cardiovascular reflexes. Expression of the AT1R occurs in high density within the NTS of most mammals, including humans, but the fundamental electrophysiological and neurochemical characteristics of the AT1AR-expressing NTS neurons are not known. To address this, we have used a transgenic mouse, in which the AT1AR promote...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 9, 2017 Category: Physiology Authors: Carter, D. A., Choong, Y.- T., Connelly, A. A., Bassi, J. K., Hunter, N. O., Thongsepee, N., Llewellyn-Smith, I. J., Fong, A. Y., McDougall, S. J., Allen, A. M. Tags: Research Article Source Type: research

Renal denervation attenuates hypertension but not salt sensitivity in ETB receptor-deficient rats
Hypertension is a prevalent pathology that increases risk for numerous cardiovascular diseases. Because the etiology of hypertension varies across patients, specific and effective therapeutic approaches are needed. The role of renal sympathetic nerves is established in numerous forms of hypertension, but their contribution to salt sensitivity and interaction with factors such as endothelin-1 are poorly understood. Rats deficient of functional ETB receptors (ETB-def) on all tissues except sympathetic nerves are hypertensive and exhibit salt-sensitive increases in blood pressure. We hypothesized that renal sympathetic nerves...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 9, 2017 Category: Physiology Authors: Becker, B. K., Feagans, A. C., Chen, D., Kasztan, M., Jin, C., Speed, J. S., Pollock, J. S., Pollock, D. M. Tags: Research Article Source Type: research

Spot urine protein measurements in normotensive pregnancies, pregnancies with isolated proteinuria and preeclampsia
In conclusion, women who develop isolated proteinuria at delivery have a larger increase in blood pressure than women without proteinuria and have a "microalbuminuric" phase earlier in gestation, unlike women who develop preeclampsia. These findings suggest a different mechanism of urine protein excretion in women with isolated proteinuria as compared with women with preeclampsia, where proteinuria has a more abrupt onset. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 9, 2017 Category: Physiology Authors: Kattah, A., Milic, N., White, W., Garovic, V. Tags: Research Article Source Type: research

Acute effects of angiotensin-converting enzyme inhibition versus angiotensin II receptor blockade on cardiac sympathetic activity in patients with heart failure
We examined the acute effects of the ACE inhibitor captopril (25 mg, n = 9) and the ANG II receptor antagonist losartan (50 mg, n = 10) on hemodynamics as well as total body and cardiac norepinephrine spillover in patients with chronic HFrEF. Hemodynamic and neurochemical measurements were made at baseline and at 1, 2, and 4 h after oral dosing. Administration of both drugs caused significant reductions in systemic arterial, cardiac filling, and pulmonary artery pressures (P < 0.05 vs. baseline). There was no significant difference in the magnitude of those hemodynamic effects. Plasma concentrations of ANG II were signi...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 9, 2017 Category: Physiology Authors: Azevedo, E. R., Mak, S., Floras, J. S., Parker, J. D. Tags: Research Article Source Type: research

Long-term effects of a renin inhibitor versus a thiazide diuretic on arterial stiffness and left ventricular diastolic function in elderly hypertensive patients
Arterial stiffness and cardiac function are important predictors of cardiovascular events in patients with hypertension, even with adequate blood pressure (BP) control. We evaluated whether a direct renin inhibitor, aliskiren, reduces arterial stiffness and modulates left ventricular function compared with a diuretic, hydrochlorothiazide, in elderly hypertensive patients. Twenty-one hypertensive patients [67 ± 14 (SD) yr] were randomly assigned to receive 6-mo aliskiren (n = 11) or hydrochlorothiazide (n = 10)-based therapy. We assessed β-stiffness of the local arteries, arterial elastance (Ea), and echocardiog...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 9, 2017 Category: Physiology Authors: Okada, Y., Shibata, S., Fujimoto, N., Best, S. A., Levine, B. D., Fu, Q. Tags: Research Article Source Type: research

Prenatal hypoxia and placental oxidative stress: linkages to developmental origins of cardiovascular disease
Intrauterine growth restriction (IUGR, a pregnancy complication where the fetus does not reach its genetic growth potential) is a leading cause of fetal morbidity and mortality with a significant impact on population health. IUGR is associated with gestational hypoxia; which can lead to placental oxidative stress and fetal programming of cardiovascular disease. Mitochondria are a major source of placental oxidative stress and may provide a therapeutic target to mitigate the detrimental effects of placental oxidative stress on pregnancy outcomes. A nanoparticle-mediated delivery of a mitochondrial antioxidant to the placent...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 9, 2017 Category: Physiology Authors: Aljunaidy, M. M., Morton, J. S., Cooke, C.-L. M., Davidge, S. T. Tags: Review Source Type: research

Pituitary adenylate cyclase-activating polypeptide drives cardiorespiratory responses to heat stress in neonatal mice
The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) has emerged as a principal and rate-limiting regulator of physiological stress responses in adult rodents and has been implicated in sudden infant death syndrome (SIDS). Recent studies show that PACAP plays a role in neonatal cardiorespiratory responses to hypoxia, hypercapnia, and hypothermia, but not hyperthermia, which is often associated with SIDS. Here we tested the hypothesis that, consistent with a role in SIDS, PACAP is involved in regulating the neonatal cardiorespiratory responses to severe heat. To address this, we used head-out plethysm...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 1, 2017 Category: Physiology Authors: Barrett, K. T., Daubenspeck, J. A., Wilson, R. J. A. Tags: Research Article Source Type: research

Cold-water immersion following sprint interval training does not alter endurance signaling pathways or training adaptations in human skeletal muscle
We investigated the underlying molecular mechanisms by which postexercise cold-water immersion (CWI) may alter key markers of mitochondrial biogenesis following both a single session and 6 wk of sprint interval training (SIT). Nineteen men performed a single SIT session, followed by one of two 15-min recovery conditions: cold-water immersion (10°C) or a passive room temperature control (23°C). Sixteen of these participants also completed 6 wk of SIT, each session followed immediately by their designated recovery condition. Four muscle biopsies were obtained in total, three during the single SIT session (preexercise...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 1, 2017 Category: Physiology Authors: Broatch, J. R., Petersen, A., Bishop, D. J. Tags: Research Article Source Type: research

Chronic hindbrain administration of oxytocin is sufficient to elicit weight loss in diet-induced obese rats
We report that chronic 4V infusion of OT into two distinct rat models recapitulates the effects of 3V OT to ameliorate DIO by reducing fat mass. While reduced food intake contributes to this effect, our finding that 4V OT also increases BAT thermogenesis suggests that increased energy expenditure may contribute as well. Collectively, these findings support the hypothesis that, in DIO rats, OT action in the hindbrain evokes sustained weight loss by reducing energy intake and increasing BAT thermogenesis. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 1, 2017 Category: Physiology Authors: Roberts, Z. S., Wolden-Hanson, T., Matsen, M. E., Ryu, V., Vaughan, C. H., Graham, J. L., Havel, P. J., Chukri, D. W., Schwartz, M. W., Morton, G. J., Blevins, J. E. Tags: Research Article Source Type: research

Low-carbohydrate diet induces metabolic depression: a possible mechanism to conserve glycogen
Long-term studies have found that low-carbohydrate diets are more effective for weight loss than calorie-restricted diets in the short term but equally or only marginally more effective in the long term. Low-carbohydrate diets have been linked to reduced glycogen stores and increased feelings of fatigue. We propose that reduced physical activity in response to lowered glycogen explains the diminishing weight loss advantage of low-carbohydrate compared with low-calorie diets over longer time periods. We explored this possibility by feeding adult Drosophila melanogaster a standard or a low-carbohydrate diet for 9 days and me...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 1, 2017 Category: Physiology Authors: Winwood-Smith, H. S., Franklin, C. E., White, C. R. Tags: Research Article Source Type: research

Fluorescence quenching by metal centered porphyrins and poryphyrin enzymes
Fluorescence spectroscopy and microscopy have been used extensively to monitor biomolecules, especially reactive oxygen species (ROS) and, more recently, reactive sulfide (RSS) species. Nearly all fluorophores are either excited by or emit light between 450 and 550 nm, which is similar to the absorbance of heme proteins and metal-centered porphyrins. Here we examined the effects of catalase (Cat), reduced and oxidized hemoglobin (Hb and metHb), albumin (alb), manganese (III) tetrakis (4-benzoic acid) porphyrin chloride (MnTBAP), iron protoporphyrin IX (hemin), and copper protoporphyrin IX (CuPPIX) on the fluorescence prope...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 1, 2017 Category: Physiology Authors: Olson, K. R., Gao, Y., Arif, F., Arora, K., Patel, S., DeLeon, E., Straub, K. D. Tags: Research Article Source Type: research

Chronic hypoxia alters maternal uterine and fetal hemodynamics in the full-term pregnant guinea pig
In this study the impact of chronic maternal hypoxia on fetal heart structure was evaluated using four-dimensional echocardiography with spatiotemporal image correlation and tomographic ultrasound, and uterine and umbilical artery resistance/pulsatility indexes and fetal heart function were evaluated using pulsed-wave Doppler ultrasound. Pregnant guinea pigs were exposed to normoxia (n = 7) or hypoxia (10.5% O2, n = 9) at 28–30 days gestation, which was maintained until full term (65 days). At full term, fetal heart structure and outflow tracts were evaluated in the four-chamber view. Fetal heart diastolic function w...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 1, 2017 Category: Physiology Authors: Turan, S., Aberdeen, G. W., Thompson, L. P. Tags: Research Article Source Type: research

Left ventricular diastolic dysfunction in women with nonobstructive ischemic heart disease: insights from magnetic resonance imaging and spectroscopy
Ischemic heart disease, in the absence of obstructive coronary artery disease, is prevalent in women and constitutes a major risk factor for developing major adverse cardiovascular events, including myocardial infarction, stroke, and heart failure. For decades, diagnosis was considered benign and often minimized; however, it is now known that this etiology carries much risk and is a significant burden to the health care system. This review summarizes the current state of knowledge on nonobstructive ischemic heart disease (NOIHD), the association between NOIHD and left ventricular diastolic dysfunction, potential links betw...
Source: AJP: Regulatory, Integrative and Comparative Physiology - October 1, 2017 Category: Physiology Authors: Nelson, M. D. Tags: Review Source Type: research