bluuebunny/crossref_metadata_2025 huggingface dataset:
p22phox inhibition in Skeletal Muscle Normalizes the Exaggerated Exercise Pressor Reflex in Chronic Heart Failure
Authors: Wang Hanjun , Gao Lie , Zimmerman Matthew C. , Zucker Irving H. , Wang Wei
Published: June 2021

In chronic heart failure (CHF), an overactive skeletal muscle exercise pressor reflex (EPR) results in excessive sympatho‐excitation and exercise intolerance. However, the mechanism(s) of the exaggerated EPR in CHF state remains to be determined. We recently found that muscle NADPH oxidase‐derived reactive oxygen species (ROS) plays an excitatory role in modulation of EPR function in normal rats. In this study, we used the technique of in vivo siRNA to selectively knockdown the protein expression of p22phox (a NADPH oxidase subunit) in hindlimb muscles of CHF rats in order to investigate the contribution of NADPH oxidase‐derived ROS to the exaggerated EPR in CHF. Data from western blotting and immunofluorescence experiments showed that compared with sham rats, the protein expression of p22phox in triceps surae muscle was significantly increased in CHF rats (ratio of p22phox to GAPDH: 0.32±0.03 vs. 0.15±0.02, CHF vs. Sham, n=5, P<0.05). Silencing p22phox in skeletal muscle with in vivo siRNA (1 week) dramatically decreased the protein expression by almost 70% in CHF rats. Animal experiments showed that gene silencing of p22phox in hindlimb muscles significantly attenuated the EPR‐evoked pressor response to a 30‐s static contraction induced by electrical stimulation of L4/L5 ventral roots in CHF rats (+33.1±2.8 vs. +20.8±1.5 mmHg, CHF vs. CHF+siRNA, n=5, P<0.05) whereas treatment with control siRNA has no effect on the EPR function. These data suggest that elevated muscle NADPH oxidase‐derived ROS contributes to the exaggerated EPR in the CHF state.
Impaired hypoxic exercise vasodilation in older adults
Authors: Evans Trent Douglas , Blain Gregory , Limberg Jacqueline , Kiefer Adam , Sebranek Josh , Proctor Lester , Schrage William
Published: June 2021

Research suggests exercise blood flow may be impaired in older adults. We hypothesized that forearm blood flow would be impaired during exercise in older subjects (64±3 years, n=10) compared to young controls (27±2 years, n=18), and that any impairment would be exaggerated under hypoxic conditions.

We measured forearm blood flow (FBF, Doppler Ultrasound), blood pressure (BP, Finapress), and Hb saturation (pulse oximeter) while subjects performed dynamic forearm exercise (8 kg, 20 contractions/min) for 4 minutes in normoxic (~98% SaO2) and hypoxic (80% SaO2) conditions.

BP was greater in older subjects than young controls (p<0.05), therefore FBF measures were normalized for perfusion pressure (FVC=FBF/BP). FVC was similar between groups at rest and steady‐state exercise in normoxia and hypoxia (p>0.05). FVC did not increase in either group from normoxia to hypoxia at rest (p>0.05). During hypoxic exercise, young subjects increased FVC from normoxic levels (p<0.05); older subjects did not (p>0.05).

These preliminary results suggest that forearm exercise vasodilation is preserved in older adults under normoxic conditions, but impairments may exist when responding to hypoxia during exercise.

Support: AFAR A08235, AHA 0815622G, APS UGSRF, NIH HL091397
Effect of short‐term training on markers of inflammation in a swine model of atherosclerosis
Authors: Masseau Isabelle , Bowles Douglas K
Published: June 2021

Endothelial dysfunction and inflammation (i.e. vascular cell adhesion molecule‐1 [VCAM‐1] expression), are early events in the development of atherosclerosis. Short‐term exercise training (Ex) enhanced endothelium‐dependent dilation (EDD) in coronary and brachial arteries. The objective of the study was to determine if Ex reduces endothelial inflammation. 3 year‐old female Yucatan miniature swine ran on a treadmill for 1 h, at 3.5 mph, once daily for 7 consecutive days. VCAM‐1 expression in the left common carotid artery (CCA) was determined by contrast‐enhanced ultrasound with VCAM‐1‐targeted microbubbles and immunoblot. In vivo measurement of luminal diameter changes in response to acetylcholine (10−7 M and 10−6M) revealed no changes in EDD in the left CCA with Ex. Immunoblot results indicate a trend for VCAM‐1 reduction in the left CCA without associated change in eNOS protein. In brachial and femoral arteries, VCAM‐1 and eNOS expression were slightly increased while in the right coronary artery, VCAM‐1 expression was slightly decreased and eNOS expression slightly increased with Ex, although these changes were not significant. Short‐term exercise appears to have minimal effect on inflammation in peripheral conduit arteries and on EDD of the left CCA. Supported by NIH HL052490
Diverse Effects of Exercise on Myofilament Function in Pathologic Left Ventricular Hypertrophy and Dysfunction
Authors: van Deel Elza Dianne , de Boer Martine , Boontje Nicky M , de Waard Monique , van der Velden Jolanda , Duncker Dirk J
Published: June 2021

Effects of exercise (EX) on pathologic left ventricular (LV) remodelling and dysfunction remain incompletely understood. Here we studied the effects of 8 weeks voluntary EX on LV and myofilament function in mice with myocardial infarction (MI) or pressure‐overload by transverse aortic constriction (TAC). Eight weeks after TAC or MI, LV geometry and function were measured and isometric force determined in single permeabilized cardiomyocytes. MI and TAC induced LV hypertrophy, interstitial fibrosis and LV dilation as well as systolic (fractional shortening, dP/dtP40) and diastolic (dP/dtmin, end‐diastolic pressure [LVEDP]) dysfunction. Cardiomyocyte maximal force development (Fmax) was lower in MI, but unexpectedly elevated in TAC, coinciding with more pronounced LV systolic dysfunction in MI compared to TAC. Conversely, passive isometric myofilament force (Fpas) was elevated in TAC but unchanged in MI, coinciding with an elevated LVEDP in TAC. EX ameliorated LV dysfunction and fibrosis and increased Fmax after MI, without effecting Fpas. In contrast, EX had no effect on either LV dysfunction or Fmax in TAC mice. EX aggravated interstitial fibrosis, but did not further increase LVEDP, likely as a result of an EX‐induced decrease in Fpas. In conclusion, effects of EX on LV dysfunction depend critically on the underlying pathology which are in part explained by the diverse effects of EX on myofilament function.
Skeletal muscle metaboreflex overactivity is partially corrected by decreasing superoxide within the nucleus tractus solitarius of hypertensive rats
Authors: Murphy Megan N , Mizuno Masaki , Smith Scott A
Published: June 2021

Studies suggest the skeletal muscle metaboreflex (SMM) is overactive in hypertension and contributes to the exaggerated mean arterial pressure (MAP) response to exercise in this disease. The mechanisms responsible for abnormal SMM activity remain undetermined. Afferent information generated by the SMM is processed within the nucleus tractus solitarius (NTS) of the brainstem. In normotensive Wistar‐Kyoto (WKY) rats, the production of nitric oxide (NO) within the NTS buffers SMM activity. However, in spontaneously hypertensive rats (SHR), the production of the NO scavenger superoxide is elevated in the NTS. Increased production of superoxide may reduce the amount of NO available to buffer SMM activity. Therefore, we hypothesized that decreasing superoxide in the NTS reduces SMM overactivity in hypertension. In decerebrate WKY and SHR, the SMM was activated by injecting capsaicin (0.3 μg/100 μL) in the arterial supply of hindlimb skeletal muscle before and after the dialysis of tempol (30μM; a superoxide oxide dismutase mimetic) in the NTS. In SHR, tempol significantly reduced the MAP response to SMM activation from 68±2 mmHg (before dialysis) to 46±4 mmHg (after dialysis). Tempol had little effect on the SMM‐mediated MAP response in WKY. The data suggest that reducing superoxide within the NTS can partially correct the exaggerated MAP response to activation of the SMM in hypertension.

Supported by NIH HL‐088422
Maturation and Differential Role of PKC Isoforms in Adrenergic, Serotonergic, and Phorbol Ester–Mediated Cerebral Artery Contractility
Authors: Chu Nina , Goyal Ravi , Goyal Dipali , Longo Lawrence D.
Published: June 2021

Protein kinase C (PKC) is a major family of kinases, containing approximately a dozen isoforms. The relative roles of each of these isoforms with maturation and contractile responses remain unclear. Thus, we tested the hypothesis that with maturation there is differential activation of PKC isoforms in response to agonist stimulation. We used cerebral arteries from fetal (~140 days) and non‐pregnant adult sheep for arterial tension measurement in response to the agonists phenylephrine (PHE), serotonin (5‐HT), and phorbol 12,13‐dibutyrate (PDBu) stimulation in the presence of specific PKC isoform inhibitors. We quantified mRNA using real‐time PCR. In both fetal and adult cerebral arteries: PHE, 5‐HT, and PDBu induced contractile responses, and these were completely inhibited by pan‐PKC inhibitory peptides. In the fetus, PKCα played a significantly greater role in 5‐HT‐ and PHE‐ induced contractions, as compared to adult. Also, in the fetus, PKCβ had a significantly greater role in PHE‐ and PDBu‐ induced contraction. Despite the varying contractile effects, PCR indicate significantly higher levels of PKC α, β, and ε mRNA levels in adult cerebral vessels, as compared to fetus. Overall, our results demonstrate activation of different PKC isoforms during fetal and adult life, with different agonists, which may be involved in fine‐tuning cerebral vascular tone and blood flow. Supported by NIH Grant HD3807‐37 to LDL.
The effects of aging on muscle loss and NF‐κB levels of various tissues in rats
Authors: LaGuire Tiev C. , Kohlen Corinne R. , Reaves Scott K.
Published: June 2021

The objective of the study was to examine the influence of aging on food intake, tissue and organ mass and the levels of NF‐κB in various tissues were examined. The transcription factor, Nuclear Factor Kappa‐B (NF‐κB), is associated with both catabolic and anabolic pathways of muscle metabolism and may be involved in age‐related muscle loss. Adult male Sprague‐Dawley rats, aged 6 (Adult) and 21 months (Old) were fed a diet for 10–17 days. Old rats consumed less grams of food per body weight (BW) each day than Adult rats (1.45% g diet/g BW vs. 2.4% g diet/g BW) although when intake data were expressed as g/diet per day there was no significant difference between groups. For skeletal muscle tissue, the average mass of gastrocnemius and soleus (g muscle/g BW) was significantly lower in Old rats but there was no difference for tibialis anterior. Levels of NF‐κB (p65 or RelA) were measured by Western blot analysis in gastrocnemius, tibialis anterior, quadriceps, soleus, lung, heart, kidney and liver. NF‐κB levels were higher in gastrocnemius of Old rats as compared to Adult rats. There were no significant age‐specific differences in NF‐κB levels in any other tissue examined. Interestingly, the level of NF‐κB was highest in lung in both age groups as compared to any other tissue. Data from this study suggest that aging affects muscle loss and NF‐κB in a tissue‐specific manner.
Clofibric Acid has Positive Inotropic Effects on Cardiac Muscle
Authors: Kim Seo‐Hyun , Mirza Omer M , Stone Jessica K , Touchberry Chad D , Youssef Jihan , Badr Mostafa , Wacker Michael J
Published: June 2021

Fibrates are a class of drugs used clinically to increase levels of HDL and to lower triglycerides. Preliminary data demonstrated that clofibric acid inhibited the Na+/K+ pump. Consequently, we hypothesized that blocking the Na+/K+ pump in cardiac tissue would lead to an increase in intracellular Na+. This would result in activation of the reverse mode of the Na+/Ca2+ exchanger and increase both intracellular Ca2+ and cardiac contractility. To test this hypothesis, mouse left ventricular heart strips were paced in the presence of either vehicle (DMSO) or clofibric acid (2 and 20 μM). Following a 20 minute exposure, analysis of individual contractions demonstrated increased height, slope, area under the curve, and tau (rate of decay) in clofibric acid‐treated strips as compared to vehicle. In summary, clofibric acid had a positive inotropic effect on mouse cardiac left ventricular muscle, most likely through a PPAR‐independent mechanism. It is possible that other analogs of clofibric acid currently prescribed in practice may also have positive inotropic effects on cardiac muscle.
Resting arterial blood pressure (ABP), sympathetic control of resting ABP, and hypertensive responses to 7‐days of intermittent hypoxia are similar in rats bred for low and high aerobic capacity running
Authors: Sharpe Amanda Lea , Andrade Mary Ann , Herrera‐Rosales Myrna , Calderon Alfredo , Britton Steven L , Koch Laura G , Toney Glenn M
Published: June 2021

Rats bred (generation 23) for low aerobic capacity running (LCR) and high aerobic capacity running (HCR) were studied. Body mass was significantly (P<0.001) greater in age‐matched male LCR (658 ± 35 g) than HCR (442 ± 43 g) rats. Telemetric recording of baseline ABP and HR in conscious rats revealed no statistical differences between stains. To test for differences in the contribution of sympathetic nerve activity (SNA) in the maintenance of ABP, ganglionic transmission was blocked in conscious rats with hexamethonium (20 mg/kg, iv). Within 5–10 minutes, mean ABP (MAP) fell to a similar level in LCR (n=4) and HCR (n=5) rats. Next, rats were exposed to intermittent hypoxia (IH; 3 min 21% O2 ‐ 3 min 10% O2, 8am–4pm) for 7 days to mimic the bouts of hypoxemia that occur in humans with sleep apnea. IH increased MAP from 101 ± 1 to 106 ± 1 mmHg in LCR rats (n=5) and from 104 ± 1 to 108 ± 1 mmHg in HCR rats (n=4). These findings indicated that resting ABP and its maintenance by ongoing SNA do not differ as a function of aerobic running capacity, in spite of clear differences in body mass between LCR and HCR rats. Similarly, differences in aerobic running capacity and body mass are not associated with different hypertensive responses to IH exposure. Support: HL088052, HL076312 (GMT), and RR 17718 (SLB and LGK).
Functional Effects of Endogenous BDNF in the Nucleus Tractus Solitarius (nTS)
Authors: Clark Catharine Grace , Kline David D. , Kunze Diana L. , Katz David M. , Hasser Eileen M.
Published: June 2021

BDNF and its receptor, TrkB, are expressed in the nTS, the principal relay site for cardiorespiratory sensoryinput in the brainstem. Studies from our laboratories demonstrate BDNF plays a sympathoexcitatory role in vivo and modulates neurotransmission between visceral afferents and nTS neurons in vitro. To determine an endogenous role for BDNF in the nTS, we examined its expression and function in Sprague Dawley rats. Immunohistochemistry (IHC) was used to determine expression. Mean arterial pressure (MAP), heart rate (HR) and lumbar sympathetic nerve activity (LSNA) responses to BDNF manipulation in the nTS were recorded in vivo. IHC demonstrated BDNF was localized to the solitary tract and neuropil and co‐localized with Synaptophysin (synaptic terminal marker), but not with MAP2 (dendritic marker). Unilateral microinjection of BDNF (30 nl) dose dependently increased MAP, HR and LSNA. In the presence of AntiBDNF, a BDNF scavenging antibody, the response to BDNF was abolished. Bilateral nTS blockade of TrkB receptors using K252a (20μM; 90 nl) decreased MAP, HR and LSNA (Δ −6 ± 2 mmHg, −19 ± 5 bpm, −24.5 ± 7 % respectively), responses similar to AntiBDNF alone (10 μg/ml; 90 nl). Vehicle controls (aCSF or IgY) had no effect. These data suggest BDNF is localized at visceral afferent synapses and that autonomic regulation in the nTS is subject to endogenous modulation by BDNF, mediated by its receptor, TrkB. NS057398 (DMK)
Cardiovascular responses to ATP into the nucleus of the solitary tract in AV3V‐lesioned rats
Authors: DE PAULA PATRICIA M. , ZANELLA DAIANA C. , TAKAKURA ANA C. , COLOMBARI EDUARDO , MENANI JOSE V.
Published: June 2021

Adenosine‐5□Œ‐triphosphate (ATP) and glutamate injected into the nucleus of the solitary tract (NTS) in awake rats increase mean arterial pressure (MAP) and reduce heart rate (HR). Electrolytic lesions of the anteroventral third ventricle (AV3V) reduce pressor response produced by glutamate into the NTS and studies have shown connections between the AV3V and NTS. Thus, in the present study, we investigated the effects of acute (1 day) electrolytic lesions of the AV3V region on the pressor and bradycardic responses induced by ATP into the NTS in unanesthetized rats. Male Holtzman rats with sham or electrolytic (2 mA × 10 s) AV3V lesions and a stainless steel cannula implanted into the NTS were used. The pressor response produced by injections of ATP (2.5 nmol/100 nl) into the NTS was reduced in 1 day AV3V‐lesioned rats (28 □} 3 mmHg, vs. sham lesions: 42 □} 3 mmHg, p<0.05). In the same AV3V‐lesioned rats, glutamate (5 nmol/100 nl) injected into the NTS reduced MAP (−29 □} 3 mmHg), while in sham rats glutamate induced pressor responses (51 □} 7 mmHg). The bradycardia to ATP into the NTS were reduced in AV3V lesioned rats (−65 □} 14 bpm, vs. sham lesions: −153 □} 14 bpm, p<0.05). The results show that AV3V lesions reduce the cardiovascular responses to ATP into the NTS, similar to previously demonstrated for glutamate into the NTS, reinforcing the importance of the AV3V region for the cardiovascular responses produced by the activation of NTS.
Oxytocin (OXT)‐immunoreactive axons closely appose tyrosine hydroxylase (TH)‐immunoreactive neurons in the rat nucleus of the solitary tract (NTS) and dorsal vagal motor (DMV) neurons that supply the gastrointestinal tract
Authors: Llewellyn‐Smith Ida J. , Travagli R. Alberto , Browning Kirsteen N
Published: June 2021

It has long been known that catecholaminergic NTS neurons provide synaptic input to vagal preganglionic neurons of the DMV. Cholinergic and catecholaminergic DMV neurons, in turn, supply the motor innervation to the gastrointestinal tract, from the lower esophagus to the transverse colon Axons of paraventricular hypothalamic neurons release OXT that modulates DMV neurons via both pre‐ and postsynaptic sites of action. The aim of the present study was to investigate whether OXT inputs directly target DMV or NTS neurons. We used double (TH+OXT) and triple (TH+OXT+ChAT) immunoperoxidase labelling to determine whether OXT axons closely apposed catecholaminergic NTS and/or DMV neurons. We also assessed OXT input to DMV neurons retrogradely labelled with cholera toxin B subunit from the corpus or ileum. OXT axons were most numerous in the caudal DMV and in the lateral aspects of the rostral DMV, but were sparsely distributed in the NTS. Close appositions by OXT axons occurred on TH‐positive NTS neurons and DMV neurons, as well as on DMV neurons projecting to either the ileum or corpus. These results suggest a prominent role of OXT in controlling different subpopulations of neurons in the dorsal vagal complex circuitry that controls gut function.

Support: NH&MRC of Australia and NIH grant DK55530
ASIC2 dependent activation of the baroreceptors is required for the arterial baroreflex
Authors: Sabharwal Rasna , Morgan Donald , Whiteis Carol A , Rahmouni Kamal , Chapleau Mark W. , Abboud Francois M.
Published: June 2021

We have shown that deletion of acid‐sensing ion channel (ASIC2) impairs baroreflex (BR) control of the circulation. This impairment may result from loss of baroreceptor sensitivity or loss of central neuronal responsiveness, or both. In these experiments we tested the contribution of the two components by inducing a reflex increase in arterial pressure with bilateral carotid occlusion (BCO) in WT (n=6) and congenic ASIC2 null mice (n=6). BCO reduces abruptly the arterial pressure (BP) in the carotid sinuses triggering a reflex increase in systemic BP which in turn is buffered by activation of the intact aortic baroreceptors and the aortic depressor nerves (ADNs). We found that the reflex increase in BP integrated over a 20 second period of BCO averaged 134±14 and 141±15 mmHg·sec in WT and ASIC2−/− respectively. However, following bilateral section of the ADNs, the increase in BP more than doubled in WT mice (to 283.4±20.3 mmHg·sec), but was unchanged in KO mice (143.8±13.8 mmHg·sec) suggesting that the buffering influence of the ADNs seen in the WT prior to their section was dependent on the presence of ASIC2. We then tested the central mediation of the BR by electrically stimulating ADN and recording the reflex decreases in heart rate (HR) and BP. As seen below, the centrally mediated activation of the BR was similar in the ASIC2 KO (n=9) and WT (n=7) mice.

Responses to ADN stim.
WT
ASIC2−/−

ΔHR (beats/min)
10 Hz
−16.9±2.5
−16.1±2.4

20 Hz
−52.8±10.8
−45.2±5.9

30 Hz
−81.3±15.9
−81.1±11.6

ΔBP (mmHg)
10 Hz
−5.6±2.4
−8.7±3.3

20 Hz
−17.5±4.5
−19.1±5.7

30 Hz
−26.4±5.4
−30.1±5.5

We conclude that ASIC2 is an essential determinant of the arterial baroreflex primarily by virtue of its contribution to mechanosensitivity of the arterial baroreceptors and not by altering the central mediation of the baroreflex. This work was supported by NIH grant HL14388
Effect of pyridostigmine on the sympathovagal balance and cardiac morphometry in heart failure
Authors: Lataro Renata M , Silva Carlos Alberto A , Prado Cibele M , Rossi Marcos A , Fazan Rubens , Salgado Helio C
Published: June 2021

Sympathovagal balance and cardiac morphometry were evaluated in heart failure (HF) rats, 4 weeks after treatment with the reversible acetylcholinesterase inhibitor pyridostigmine (PYR). HF was produced by left coronary artery ligation under anesthesia. Conscious animals were equipped with catheters in the femoral artery and vein. Methyl atropine and propranolol were used to evaluate the sympathovagal balance and the intrinsic heart rate (IHR). In HF rats PYR reduced heart rate (Control: 335±5; HF: 388±11; HF+PYR: 347±4 bpm), increased vagal tone (Control: 92±13; HF: 40±8; HF+PYR: 107±9 bpm), reduced sympathetic tone (Control: 19±4; HF: 47±9; HF+PYR: 23±5 bpm) and did not change IHR (Control: 377±5; HF: 392±6; HF+PYR: 394±8 bpm) or cardiac/body weight ratio (Control: 2.9±0.1; HF: 3.5±0.1; HF+PYR: 3.6±0.1 mg/g). However, PYR reduced the diameter of the myocytes from the left ventricle (Control: 13.2±0.2; HF: 19.9±0.6; HF+PYR: 17.0±0.5 ìm). In conclusion, it was demonstrated that pyridostigmine increased cardiac vagal tone and reduced the sympathetic tone without changing the IHR of HF rats. In addition, PYR reduced the diameter of the myocytes from the left ventricle.

Support: FAPESP, CNPq and CAPES.
Maternal Diabetes Increases Small Conductance Ca2+‐activated K+ (SK) Currents Which Alters Action Potential Properties and Excitability of Cardiac Motoneurons in the Nucleus Ambiguus
Authors: Lin Min , Chen Qing‐Hui , Li Lihua , Wurster Robert D , Cheng Zixi (Jack)
Published: June 2021

Maternal diabetes (MD) impairs baroreflex control of heart rate. PCMNs play a key role in the baroreflex. We examined the effects of MD on excitability, action potential (AP) properties and SK channels of PCMNs. Neonatal mice from OVE26 diabetic (Type 1) mothers (NMDM) and normal FVB mothers (control) were used. XRITC was injected into the pericardial sac at P7–9 to label PCMNs. Two days later, XRITC‐labeled PCMNs in slices were identified. Whole‐cell (current and voltage) clamps were used to measure spike frequency, repolarization (half‐width), afterhyperpolarization (AHP), outward currents, and afterhyperpolarization currents (IAHP). Compared to control, we found (p<0.05) in NMDM that: 1) spike frequency decreased; 2) the half‐width and AHP peak amplitude increased; 3) the peak amplitude of outward transient currents and IAHP increased; 4) Cd2+ (Ca2+ channels blocker)‐sensitive transient outward currents and IAHP increased; 5) application of Cd2+ increased AP half‐width and decreased AHP amplitude; 6) apamin‐sensitive transient outward currents and IAHP increased; 7) blockade of SK channels with apamin increased AP half‐width and decreased AHP amplitude; 8) apamin application increased the firing rate to current injections and largely abolished the difference of the firing rate between control and NMDM. We suggest that the augmented SK currents may contribute to altered AP properties and the attenuated excitability of PCMNs in NMDM. NIH R01 HL79636.
ASIC3 in dorsal root ganglion neurons contributes to femoral occlusion enhanced sympathetic responsiveness
Authors: Liu Jiahao , Xing Jihong , Gao Zhaohui , Li Jianhua
Published: June 2021

Acid sensing ion channel subtype 3 (ASIC3) is responsive to acid in the extracellular medium. Prior studies suggest that muscle metabolite lactic acid and ASIC play a role in muscle afferent mediated reflex sympathetic response. Also, femoral occlusion increases the reflex sympathetic nerve response. Thus, we tested the hypothesis that enhanced ASIC3 expression and its responsiveness in primary afferent neurons innervating muscles contribute to the exaggerated reflex sympathetic responses after femoral occlusion. The femoral occlusion was induced by the femoral artery ligation in rats. First, we employed Western blot to examine expression of ASIC3 in dorsal root ganglion (DRG). The data showed that 24 hrs of femoral occlusion led to upregulation of ASIC3 expression in DRG (optical density: 0.93 ± 0.08 in control vs. 1.47 ± 0.04 after occlusion, P<0.05), e.g. 1.58‐fold increase. Second, experiments using whole cell patch‐clamp demonstrated that current amplitude of DRG neurons innervating muscle was larger in response to a lower pH in femoral occlusion. Third, responses of renal sympathetic nerve activity and blood pressure to acid injected into the arterial blood supply of hindlimb muscles were also enhanced after the ligation. This study suggests that ASIC3 has an important contribution to augmented sympathetic responsiveness after femoral occlusion. (Supported by R01 HL078866 and R01 HL090720).
A Developmentally Non‐coding RNA regulates A. nidulans SYG1 plus gprB
Authors: Alcocer Jose Guadalupe , Miller Karen , Miller Bruce
Published: June 2021

Mating type genes control self/non‐self recognition during fertilization, karyogamy and meiosis in the filamentous fungi. Aspergillus nidulans matA is a homolog of the human sex‐determining factor SRY. The developmentally regulated matA gene shows strict chromosomal position effect, suggesting that epigenetic events could be involved in silencing its expression in a sub‐population of cells. This chromosomal domain includes other coordinately regulated genes, one of which is a non‐coding RNA, jgaA. This non‐coding RNA is a member of a large family of eukaryotic RNAs that represent genomic “dark matter” and which have potential roles in gene silencing. Transcription of jgaA and SYG1, a human homolog of the Xenotropic and polytropic retrovirus receptor (XPR1), are convergent with a 30 bp overlap. Northern Blot analysis demonstrated that jgaA is co‐regulated with matA during sexual development in A. nidulans. A gene deletion of the jgaA shows a 42% decrease in the number of cleistothecia produced per plate. Quantitative RT‐PCR has revealed an up‐regulation of the G protein‐couple receptor (gprB), and change the expression level of SYG1 in the null strain. As well, qRT‐PCR has shown jgaA to be a gene regulator of SYG1 dependent on the RNA interference pathway.
Immunoregulation by the neurohypophysis
Authors: Quintanar‐Stephano Andrés , Villalobos Criseida , Arroyo Karla , Organista Alejandro , Tinajero Manuel , Chavira Roberto , Ventura Javier , Muñóz Martín , Campos Rafael , Reyna Humberto , Kovacs Kalman , Berczi Istvan
Published: June 2021

The role of the neurohypophysial hormones on immunoregulation has not been completely elucidated. To obtain a deeper insight, groups of Lewis rats were subjected to sham operation (SHAM), anterior (AL) or neurointermediate pituitary lobectomy (NIL) or total hypophysectomy (HYPX) and immunized for adjuvant induced arthritis (AIA) or experimental autoimmune encephalomyelitis (EAE). Intact control groups were included for reference. Groups were sacrificed 15 days postimmunization. Serum levels of PRL, ACTH and AVP, and spleenic ILs mRNA expression and macrophages number were assessed. In the AIA experiment, SHAM animals showed normal PRL, ACTH and AVP serum levels, increased expression of ILs 1 and 12, no changes in the remaining ILs, and significant increase in macrophages number. In the AL rats, normal AVP and low PRL and ACTH serum levels occurred. Except TNFα, ILs‐1,‐2,‐6,‐10,‐12, INFγ and macrophages number were significantly increased. In NIL rats, low AVP and normal PRL and ACTH levels occurred, and no alterations in ILs expression and macrophages number were found. In HYPX animals, low PRL, ACTH and AVP were apparent, while ILs‐1 and ‐12 and macrophages number were significantly increased. In general, similar results were obtained in EAE groups. The results indicate that immune responses can occur in absence of the pituitary gland and that AVP is an important immunoregulator.

Supported by UAA and CONACYT. México
Behavioral Actions of Neuropeptide W: More Evidence for a Role in the Stress Response
Authors: Pate Alicia Nicole , Samson Willis K
Published: June 2021

Neuropeptide W (NPW), an endogenous peptide ligand for GPR7 and GPR8, is produced in hypothalamic and brain stem regions important in the neuroendocrine, behavioral and autonomic responses to stress. Indeed, we demonstrated that central administration of NPW activated the hypothalamo‐pituitary adrenal axis (HPA). We then determined if NPW could alter locomotor activity or mean arterial pressure (MAP), two additional markers of the stress response. Lateral cerebroventricle (i.c.v.) cannulae were implanted in adult male rats 5 days before experimentation. In behavioral testing, basal activity was monitored for 1 hr prior to the administration of saline, 0.1, 0.3, 1, or 3 nmol NPW23 i.c.v. and behavior was monitored for 2 hr. For cardiovascular experiments, a cannula was implanted into the carotid artery. On the following day after recording baseline MAP, rats were injected with 1 nmol NPW23 i.c.v., and MAP was recorded for 1 hr. NPW treatment increased total locomotor activity in a dose‐related manner, and increased stereotypy and ambulatory activity, but did not significantly alter MAP, indicating NPW alters endocrine and behavioral responses to stress without inducing the cardiovascular effects.
Nicotinic acid improves reverse cholesterol transport in dogs
Authors: Le Bloc'h Jérôme , Leray Véronique , Magot Thierry , Krempf Michel , Nguyen Patrick , Ouguerram Khadija
Published: June 2021

Nicotinic acid (NA) improves plasma lipids but the involved mechanisms have not been fully elucidated. A higher HDL‐cholesterol (HDL‐C) concentration has been observed in humans, and the role of cholesteryl ester transfer protein (CETP) in this raise remains to be determined. With this aim, we assessed the NA effect on the reverse cholesterol transport (RCT) in the dog, which is a CETP‐devoid species. RCT was assessed through stable isotope endogenous labeling of HDL‐C and apoAI moieties. NA treatment lowered triglyceride (TG) plasma concentration (p < 0.01) due to a diminution in VLDL‐TG (p < 0.05). Cholesterol plasma concentration was reduced (p < 0.0001) as a result of lowered concentration of both LDL‐C (p < 0.05) and HDL‐C (p < 0.0001). Kinetic studies showed a higher cholesterol esterification rate (p < 0.05) that was in accordance with a rise in cholesterol efflux as measured in vitro (p < 0.05). Cholesterol turnover was accelerated via selective uptake of both HDL and cholesterol esters that explain the HDL‐C reduction (p < 0.05 for both). In conclusion, this study shows that, in CETP‐devoid species as dogs, NA would lower HDL due to a higher catabolism, which would reflect a more active RCT. Moreover, in humans or in other CETP species, NA could also raise HDL‐C as a result of a reduction in plasma TG. Since it has been shown a higher HDL‐C concentration after NA treatment, this second effect should be predominant in human.
CHRONIC HYPOXIA DECREASES THE EXPRESSION OF PKC EPSILON AND ALTERS METHYLATION STATUS OF PKC EPSILON PROMOTER IN H9c2 CELLS
Authors: Patterson Andrew
Published: June 2021

Recent studies have demonstrated that chronic hypoxia during fetal development significantly decreased PKCε protein expression in the heart of adult offspring resulting in an increased heart susceptibility to ischemia and reperfusion injury. We tested the hypothesis that chronic hypoxia directly affects PKCε expression and alters methylation status of PKCε promoter in embryonic rat cardiac H9c2 cells. Cells were grown and divided into four groups, exposing to 21%, 10.5%, 3%, and 1% O2, respectively, for 24 hours. Protein and mRNA were isolated and Western immunoblotting and real‐time PCR were performed to determine the expression levels of PKCε. For methylation studies, DNA was isolated from H9c2 cells exposed to either 21% or 1% O2 and treated with sodium bisulfite. Sodium bisulfite differentially converts all unmethylated, but not methylated cytosines to uracil. Methylation‐specific PCR was performed to assess the methylation status of transcription binding sites. We found cells treated with 1%, but not 10.5% and 3% O2, had significantly decreased PKCε protein and mRNA levels. Furthermore, 1% O2 increased methylation of both SP1 bindings sites (−346, and −268) at PKCε promoter. ChIP assays demonstrated 1% O2 significantly decreased SP1 binding to PKCε promoter, which was restored in the presence of 5‐aza‐2′‐deoxycytidine (DNA methylation inhibitor). Similarly, the addition of 5‐aza‐2′‐deoxycytidine blocked the hypoxia‐induced increase in methylation of both SP1 binding sites and restored PKCε mRNA and protein to the control levels. These findings suggest that chronic hypoxia decreases PKCε expression through increase methylation for SP1 binding sites at PKCε promoter in H9c2 cells.
EFFECTS OF DIETARY CARBOHYDRATES ON MINERAL METABOLISM IN LACTATING DAMS AND THEIR PUPS
Authors: Douard Veronique , Asgerally Abbas , Shapses Sue , Sabbagh Yves , Ferraris Ronaldo
Published: June 2021

Dramatic increases in fructose (F) consumption in the last 40 y have been tightly linked to obesity, insulin resistance and other metabolic abnormalities in adults. However, there is no information about the effects of F on maternal and fetal health. To evaluate the specific effects of excessive F and glucose consumption during gestation and lactation on dams and their litters, 3 groups of female rats were fed isocaloric, isolipidic 60% glucose, F or starch diets for 40 d, from day 2 of gestation to end of lactation. Compared to dams fed glucose and starch, dams fed F had lower rates of intestinal transepithelial Ca transport as well as lower levels of intestinal Ca and calbindin 9K protein, plasma Ca and plasma 1,25‐vitamin‐D. Dams fed glucose or F exhibited lower rates of transepithelial Pi transport, levels of plasma Pi, bone mineral content and bone mineral density (BMD). These marked perturbations in mineral homeostasis resulted in modest decreases in BMD as well as growth rates of pups from F‐fed dams. Our novel findings clearly show that over‐consumption of F and perhaps glucose during pregnancy and lactation impairs bone health of the dams because of decreases in active intestinal Ca and Pi transport caused by impaired production of 1,25‐vitamin D. Dams may mobilize bone Ca and Pi stores to dampen perturbations in mineral homeostasis transmitted to the offspring. (NIH RDK075617, NSF 722365)
Continuum of Basic & Clinical Neurosciences across the Entire Curriculum
Authors: Jozefowicz Ralph F
Published: June 2021

Neurophobia is the fear of neural sciences and clinical neurology that medical students develop due to their inability to apply their basic science knowledge to clinical situations. The treatment for neurophobia is to ensure a strong basic science/clinical integration in all years of the medical school curriculum, resulting in a continuum of neurologic education. The 2nd year Mind, Brain and Behavior (MBB) course at the University of Rochester integrates neural sciences, neuropathology, psychopathology and psychopharmacology in a 9‐week modified PBL format. Neurology and psychiatry faculty, many of whom have MD/PhD's, deliver the bulk of the lectures, and residents serve as PBL tutors and laboratory instructors alongside the faculty. Involvement of clinical faculty and residents in teaching the MBB course not only helps insure that the material taught is clinically relevant, but it also eases the transition to the 3rd year clerkships. The outcomes for the MBB course have been uniformly positive. Not only have students consistently rated MBB as the best basic science course in the curriculum, but their performance on the NBME subject test in neurosciences has been significantly higher than the national mean. A neuroscience course that integrates basic science and clinical neurology is likely to prepare students well for the new USMLE gateway examination. And neurophobia might even be replaced by neurophilia!
Mineralization of breast capsular tissue: changes in factors affecting apatite formation and growth
Authors: Hunter Larry W , Tran Nho V , Miller Virginia M
Published: June 2021

Experiments were designed to investigate isolatable factors that could either promote or inhibit formation of hydroxyapatite (HA) crystals associated with mineralization of the fibrous capsule surrounding silicone breast implants. Explanted capsular tissue was minced, filtered (0.2μm), inoculated into culture plates containing DMEM/10% FBS and kept at 37°C, 95%O2. Within 14 days, biofilm‐like and suspending (planktonic) aggregates containing HA formed to a greater extent in plates inoculated with sample from calcified (CC) than non‐calcified (NC) capsules (158 vs 4 nephelometric turbidity units, respectively). Confocal microscopy of formalin‐fixed sections of NC showed the major cell types to be macrophages and fibroblasts. These cells were immunopositive for fetuin, a blood protein. In contrast, CC were largely fibrous; fetuin labeling was sparse except for the calcific plaque itself on the surface of the capsule adjacent to the implant. Thus, a factor which affects HA formation, possibly a HA nucleator, or a modifier of nucleator activity, can be isolated from mineralized fibrous breast capsules. Localization of fetuin within NC but not CC cells is consistent with its known role in inhibiting HA crystal growth. Supported by grants from the Fetzer Foundation, NIH HL88988 and Division of Experimental Surgery, Mayo Clinic.
Website Resources versus Text Resources: Which do Millenneal Medical Students Utilize Most?
Authors: Osborne David Lee , Busselberg Dietrich , Janssen Herbert F.
Published: June 2021

In the modern era of internet access to a vast world of information, The accuracy of and use of this information by students has significant implications on academic performance. In the past, knowledge was passed from teacher to student via verbal interaction. In more recent times, introduction of modern printing technologies has led to a plethora of printed text information being available to students. Most recently, the advent of the internet introduced a new wrinkle in this delivery of information. Students today have access to faculty delivery of information, textual delivery of information and internet/website delivery of information. Faculty training and peer review for text material minimize perpetuation of incorrect information being transferred to the students. However, use of internet/website based information presents a different scenario. Much of the information available on the internet has been scrutinized, reviewed and analyzed, yet a significant portion of the information is potentially less than accurate and has not been analyzed or reviewed. The biggest problem here is that the student cannot assess the accuracy of the information. Survey of our current class indicates that these students access 57.5 % of their reading information from website sources and 42.5 percent of their information from textual sources. 73% indicated a greater reliance on web based information over textual information.
Courses in modeling transport and metabolism in cardiovascular and respiratory systems
Authors: Raymond Gary M. , Butterworth Erik A. , Bassingthwaighte James B.
Published: June 2021

Quantitative analysis is essential to integrate knowledge systematically from genome through molecular and cell biology to understand how organs and organisms function. On June 14–18, 2010 and August 23–27, 2010, the National Simulation Resource in the Department of Bioengineering, University of Washington, Seattle, is giving modeling courses on transport, pharmacokinetics and metabolism in cardiovascular and respiratory systems for clinical and research scientists. The focus is on approaches to data analysis, on using mathematical models for precisely defining hypotheses, designing experiments and evaluating the fitting of models to data. Participants are encouraged to bring data and models for group discussion. Starting with computer models from www.physiome.org/Models, participants will develop new models using standard tools including JSim, a simulation system for building and analyzing quantitative models. JSim runs on PC, Mac, and Linux platforms and is free and downloadable from www.physiome.org/jsim/download/.

(Supported by NIH T15 HL088516.)
Voluntary Participation in Active Learning Activity Leads to a Better Understanding in Physiology
Authors: Carvalho Helena , West Crystal Ann
Published: June 2021

Students learn when they are thinking about the subject. To teach physiology we must offer opportunities for the student to actively participate in class. This aids in bringing their attention to the topic and thus generates genuine interest in the mechanisms involved. This study evaluated if a relationship existed between voluntary participation in active learning exercises and the performance on the survey. Anonymous cardio‐respiratory surveys were distributed to three groups of students: summer, fall and spring. The spring group was offered the opportunity to discuss with their teacher's assistant in a small group setting before running the BioPac lab exercise. At the end of the session students voluntarily and anonymously responded to a daily survey containing one essay question related to the lab. This activity afforded students the opportunity to explain and apply the concept. Feedback on the submitted responses was shared with the entire class at the beginning of next session and misconceptions were addressed. According to the chi‐square test of independence, students in the spring term had a better overall performance (, p<0.001) on the survey (spring = 61.9% of responses correct, fall = 49.4%, summer = 56.7%). In conclusion, when the opportunity is offered, students become active participants in the learning process translating into an improvement in their understanding of physiological concepts.
Promoting undergraduate research through the Genomics Education Partnership
Authors: Hark Amy T. , Bailey Cheryl P. , Bhalla Satish C. , Elgin Sarah C.R.
Published: June 2021

Rapid increases in DNA sequence information now permit comparative examination of genes and genome organization. The goal of the Genomics Education Partnership (GEP) is to provide undergraduate students with an opportunity to participate in a large‐scale genome sequencing and annotation project to achieve the integrated goals of enhancing student learning in bioinformatics and related fields while making a contribution to new knowledge. The current focus of the GEP is on the dot chromosomes of several Drosophila species. This unique domain warrants further study because it has properties of both euchromatin, including normal gene density, and heterochromatin, including a high density of repetitive elements. Students take ownership of stretches of sequence and work to improve the posted sequence data and generate carefully annotated gene models; their work is supported by the central resources of the GEP. The assembled data permits analysis of the chromosome organization among different Drosophila species, resulting in publication and the development of new research questions. Surveys have indicated student learning gains in knowledge of genes and genomes and also demonstrate that GEP student personal gains are similar to those of students involved in a full‐time summer research experience. This project is funded by HHMI and NIH.
Teaching of introductory courses in biological sciences may require additional measures by teachers
Authors: El‐Sabban Farouk
Published: June 2021

Teaching of introductory courses in biological sciences can be a new experience for some teachers. Students enrolled in these courses are usually young and most likely new to the academic environment, thus are in need of attentive guidance. Explaining the relevance of the course to the academic program that the student has chosen is an essential measure. Based on experience in teaching such courses at the university level and at different geographical locations, some additional measures by teachers are thought to benefit the education process. These measures include: 1) the course syllabus and learning objectives must be discussed with students in class; 2) teachers ought to provide a course calendar that contains dates of significant activities and events; 3) an initial simple questionnaire about educational background is to be completed by each student, which involves: student identity, related courses taken or being taken concurrently with the course being taught, why the student is taking this course?, and what does the student expect from the course?; 4) reminders should be made to students about deadlines for major assignments and dates of events and examinations, even if provided in the course calendar or syllabus; and 5) an anonymous feedback form is to be completed by students at the end of the course, which contains questions such as: how did the content of the course affect student's general and specific awareness of the subject matter?, what did the student like the most about the course?, what did not the student like about the course?, any suggestions for improving the course, and to make comments about the course or its teacher. Also, the use of a course‐specific e‐mail account or another available electronic medium can be of multiple benefits, which include the enhancement of communication among students and their teacher.
Immunohistochemical localisation of VEGF in Cynops pyrrhogaster teeth development
Authors: MIWA Yoko , Sunohara Masataka , SATO Iwao , SHIMADA Kazuyuki
Published: June 2021

Japanese newts, Cynops pyrrhogaster has a polyphyodont dentition that enables us to observe its tooth development thoroughly at a time with sequential appearance of teeth. Vascular endothelial growth factor (VEGF) is a key regulator of blood vessel endothelium. We examined immunohistochemical localization of VEGF and its receptors, and showed the specific expression pattern of VEGF and VEGF receptor in Cynops pyrrhogaster tooth from “dentine matrix formation and mineralixation stage” to “enameloid maturation and enamel‐like matrix formation stage”. The intensity of the immunoreactivity to VEGF and its receptor VEGF receptor‐2 (VEGFR‐2) were positive in inner enamel epithelium and odontoblasts at “dentine matrix formation and mineralixation stage”. We postulate that the different expression of VEGF in inner enamel epithelium, ameloblast and odontoblast during each stage of tooth development may affect a tooth germ formation.