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.

Role of endothelial nitric oxide in control of peripheral vascular conductance during muscle metaboreflex activation
The muscle metaboreflex is a powerful pressor reflex induced by the activation of chemically sensitive muscle afferents as a result of metabolite accumulation. During submaximal dynamic exercise, the rise in arterial pressure is primarily due to increases in cardiac output, since there is little systemic vasoconstriction. Indeed, in normal animals, we have often shown a small, but significant, peripheral vasodilation during metaboreflex activation, which is mediated, at least in part, by release of epinephrine and activation of vascular β2-receptors. We tested whether this vasodilation is in part due to increased rele...
Source: AJP: Regulatory, Integrative and Comparative Physiology - July 1, 2017 Category: Physiology Authors: Senador, D., Kaur, J., Alvarez, A., Hanna, H. W., Krishnan, A. C., Altamimi, Y. H., O'Leary, D. S. Tags: Research Article Source Type: research

Use of the hyperinsulinemic euglycemic clamp to assess insulin sensitivity in guinea pigs: dose response, partitioned glucose metabolism, and species comparisons
This study establishes a method for measuring partitioned glucose metabolism in chronically catheterized conscious guinea pigs, allowing studies of regulation of insulin sensitivity in this species. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - July 1, 2017 Category: Physiology Authors: Horton, D. M., Saint, D. A., Owens, J. A., Gatford, K. L., Kind, K. L. Tags: Research Article Source Type: research

Intermittent hypoxia training blunts cerebrocortical presenilin 1 overexpression and amyloid-{beta} accumulation in ethanol-withdrawn rats
Abrupt cessation of chronic alcohol consumption triggers signaling cascades that harm vulnerable brain regions and produce neurobehavioral deficits. We have demonstrated that a program of intermittent, normobaric hypoxia training (IHT) in rats prevents brain damage and neurobehavioral impairment resulting from abrupt ethanol withdrawal (EW). Moreover, EW induced expression of stress-activated protein kinase p38 and presenilin 1 (PS1), the catalytic subunit of -secretase that produces the neurotoxic amyloid-β (Aβ) peptides Aβ40 and Aβ42. We tested the hypotheses that 1) IHT limits EW-induced activation o...
Source: AJP: Regulatory, Integrative and Comparative Physiology - July 1, 2017 Category: Physiology Authors: Ryou, M.-G., Mallet, R. T., Metzger, D. B., Jung, M. E. Tags: Research Article Source Type: research

Sex-specific effects of stress on metabolic and cardiovascular disease: are women at higher risk?
Cardiovascular disease (CVD) has traditionally been viewed as a male disease; however, the relative risk for obesity and hypertension morbidity and mortality, major risk factors for CVD, is higher for women in the United States. Emerging epidemiological data strongly support stressful experiences as a modifiable risk factor for obesity, insulin resistance, and heart disease in women at all ages. Therefore, primary prevention of these diseases may be associated with both identifying and increasing the knowledge regarding the sex differences in emotional functioning associated with physiological responses to stress. The purp...
Source: AJP: Regulatory, Integrative and Comparative Physiology - July 1, 2017 Category: Physiology Authors: Murphy, M. O., Loria, A. S. Tags: Review Source Type: research

Sex-dependent effects of antenatal glucocorticoids on insulin sensitivity in adult sheep: role of the adipose tissue renin angiotensin system
Exposure to glucocorticoids in utero is associated with changes in organ function and structure in the adult. The aims of this study were to characterize the effects of antenatal exposure to glucocorticoids on glucose handling and the role of adipose tissue. Pregnant sheep received betamethasone (Beta, 0.17 mg/kg) or vehicle 24 h apart at 80 days of gestation and allowed to deliver at term. At 9 mo, male and female offspring were fed at either 100% of nutritional allowance (lean) or ad libitum for 3 mo (obese). At 1 yr, they were chronically instrumented under general anesthesia. Glucose tolerance was evaluated using a bol...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Massmann, G. A., Zhang, J., Seong, W. J., Kim, M., Figueroa, J. P. Tags: Research Article Source Type: research

Improved skeletal muscle Ca2+ regulation in vivo following contractions in mice overexpressing PGC-1{alpha}
In skeletal muscle, resting intracellular Ca2+ concentration ([Ca2+]i) homeostasis is exquisitely regulated by Ca2+ transport across the sarcolemmal, mitochondrial, and sarcoplasmic reticulum (SR) membranes. Of these three systems, the relative importance of the mitochondria in [Ca2+]i regulation remains poorly understood in in vivo skeletal muscle. We tested the hypothesis that the capacity for Ca2+ uptake by mitochondria is a primary factor in determining [Ca2+]i regulation in muscle at rest and following contractions. Tibialis anterior muscle of anesthetized peroxisome proliferator-activated receptor- coactivator-1&alph...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Eshima, H., Miura, S., Senoo, N., Hatakeyama, K., Poole, D. C., Kano, Y. Tags: Research Article Source Type: research

A novel biomarker associated with distress in humans: calcium-binding protein, spermatid-specific 1 (CABS1)
Calcium-binding protein spermatid-specific 1 (CABS1) is expressed in the human submandibular gland and has an anti-inflammatory motif similar to that in submandibular rat 1 in rats. Here, we investigate CABS1 in human saliva and its association with psychological and physiological distress and inflammation in humans. Volunteers participated across three studies: 1) weekly baseline measures; 2) a psychosocial speech and mental arithmetic stressor under evaluative threat; and 3) during academic exam stress. Salivary samples were analyzed for CABS1 and cortisol. Additional measures included questionnaires of perceived stress ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Ritz, T., Rosenfield, D., St. Laurent, C. D., Trueba, A. F., Werchan, C. A., Vogel, P. D., Auchus, R. J., Reyes-Serratos, E., Befus, A. D. Tags: Research Article Source Type: research

Effects of face/head and whole body cooling during passive heat stress on human somatosensory processing
We herein investigated the effects of face/head and whole body cooling during passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs) at C4' and Fz electrodes. Fourteen healthy subjects received a median nerve stimulation at the left wrist. SEPs were recorded at normothermic baseline (Rest), when esophageal temperature had increased by ~1.2°C (heat stress: HS) during passive heating, face/head cooling during passive heating (face/head cooling: FHC), and after HS (whole body cooling: WBC). The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4' and P14, N1...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Nakata, H., Namba, M., Kakigi, R., Shibasaki, M. Tags: Research Article Source Type: research

Acute hypoxia activates neuroendocrine, but not presympathetic, neurons in the paraventricular nucleus of the hypothalamus: differential role of nitric oxide
Hypoxia results in decreased arterial Po2, arterial chemoreflex activation, and compensatory increases in breathing, sympathetic outflow, and neuroendocrine secretions, including increased secretion of AVP, corticotropin-releasing hormone (CRH), adrenocorticotropin hormone (ACTH), and corticosterone. In addition to a brain stem pathway, including the nucleus tractus solitarius (nTS) and the rostral ventrolateral medulla (RVLM), medullary pathways to the paraventricular nucleus of the hypothalamus (PVN) contribute to chemoreflex responses. Experiments evaluated activation of specific cell phenotypes within the PVN following...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Coldren, K. M., Li, D.-P., Kline, D. D., Hasser, E. M., Heesch, C. M. Tags: Research Article Source Type: research

Evidence for intraventricular secretion of angiotensinogen and angiotensin by the subfornical organ using transgenic mice
Direct intracerebroventricular injection of angiotensin II (ANG II) causes increases in blood pressure and salt and water intake, presumably mimicking an effect mediated by an endogenous mechanism. The subfornical organ (SFO) is a potential source of cerebrospinal fluid (CSF), ANG I, and ANG II, and thus we hypothesized that the SFO has a secretory function. Endogenous levels of angiotensinogen (AGT) and renin are very low in the brain. We therefore examined the immunohistochemical localization of angiotensin peptides and AGT in the SFO, and AGT in the CSF in two transgenic models that overexpress either human AGT (A+ mice...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Agassandian, K., Grobe, J. L., Liu, X., Agassandian, M., Thompson, A. P., Sigmund, C. D., Cassell, M. D. Tags: Research Article Source Type: research

The normal increase in insulin after a meal may be required to prevent postprandial renal sodium and volume losses
This study tested whether the normal postprandial increase in plasma insulin significantly attenuates renal sodium and volume losses. Rats were instrumented with chronic artery and vein catheters, housed in metabolic cages, and connected to hydraulic swivels. Measurements of urine volume and sodium excretion (UNaV) over 24 h and the 4-h postprandial period were made in control (C) rats and insulin-clamped (IC) rats in which the postprandial increase in insulin was prevented. Twenty-four-hour urine volume (36 ± 3 vs. 15 ± 2 ml/day) and UNaV (3.0 ± 0.2 vs. 2.5 ± 0.2 mmol/day) were greater in the I...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Irsik, D. L., Blazer-Yost, B. L., Staruschenko, A., Brands, M. W. Tags: Research Article Source Type: research

Muscle mechanoreflex activation via passive calf stretch causes renal vasoconstriction in healthy humans
Reflex renal vasoconstriction occurs during exercise, and renal vasoconstriction in response to upper-limb muscle mechanoreflex activation has been documented. However, the renal vasoconstrictor response to muscle mechanoreflex activation originating from lower limbs, with and without local metabolite accumulation, has not been assessed. Eleven healthy young subjects (26 ± 1 yr; 5 men) underwent two trials involving 3-min passive calf muscle stretch (mechanoreflex) during 7.5-min lower-limb circulatory occlusion (CO). In one trial, 1.5-min 70% maximal voluntary contraction isometric calf exercise preceded CO to accu...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Drew, R. C., Blaha, C. A., Herr, M. D., Cui, R., Sinoway, L. I. Tags: Research Article Source Type: research

Nitric oxide-sensitive guanylyl cyclase signaling affects CO2-dependent but not pressure-dependent regulation of cerebral blood flow
Cerebrovascular CO2 reactivity is affected by nitric oxide (NO). We tested the hypothesis that sildenafil selectively potentiates NO-cGMP signaling, which affects CO2 reactivity. Fourteen healthy males (34 ± 2 yr) were enrolled in the study. Blood pressure (BP), ECG, velocity of cerebral blood flow (CBF; measured by transcranial Doppler), and end-tidal CO2 (EtCO2) were assessed at baseline (CO2 ~39 mmHg), during hyperventilation (CO2 ~24 mmHg), during hypercapnia (CO2 ~46 mmHg), during boluses of phenylephrine (25–200 µg), and during graded head-up tilting (HUT). Measurements were repeated 1 h after 100 ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Jahshan, S., Dayan, L., Jacob, G. Tags: Research Article Source Type: research

Role of leptin in energy expenditure: the hypothalamic perspective
The adipocyte-derived hormone leptin is a peripheral signal that informs the brain about the metabolic status of an organism. Although traditionally viewed as an appetite-suppressing hormone, studies in the past decade have highlighted the role of leptin in energy expenditure. Leptin has been shown to increase energy expenditure in particular through its effects on the cardiovascular system and brown adipose tissue (BAT) thermogenesis via the hypothalamus. The current review summarizes the role of leptin signaling in various hypothalamic nuclei and its effects on the sympathetic nervous system to influence blood pressure, ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 8, 2017 Category: Physiology Authors: Pandit, R., Beerens, S., Adan, R. A. H. Tags: Review Source Type: research

TLR2 knockout protects against diabetes-mediated changes in cerebral perfusion and cognitive deficits
In conclusion, these findings support the involvement of TLR2 in the pathogenesis of diabetic vascular disease and cognitive impairment. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Hardigan, T., Hernandez, C., Ward, R., Hoda, M. N., Ergul, A. Tags: Research Article Source Type: research