bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of chronic D1 partial agonist treatment on cocaine self‐administration in squirrel monkeys.
Authors: Bergman Jack , Desai Rajeev I
Published: June 2021

Dopamine receptor partial agonists have been proposed for the management of cocaine addiction. In the present studies, this medication strategy was evaluated in squirrel monkeys that were chronically exposed to the D1 partial agonist SKF 83959 via osmotic minipumps (0.1 mg/kg/hr). In one group, the effects of the D1 agonists SKF 82958 and SKF 38393 on eye blinking were studied before and during chronic treatment. In a second group, lever‐pressing was maintained under concurrent fixed‐ratio schedules of i.v. self‐administration (one lever) and food delivery (second lever); the reinforcing effects of i.v. cocaine were studied before and during chronic treatment. Results show that, prechronically, the D1 agonists SKF 82958 and SKF 38393 produced dose‐related and efficacy‐related increase in rates of eye blinking. Chronic exposure to SKF 83959 produced tolerance to these effects, reflected in >10‐fold rightward (SKF 82958) or downward (SKF 38393) shifts in the dose‐effect functions for eyeblinking. In contrast, the reinforcing strength and dose‐related intake of i.v. cocaine were unchanged during the chronic regimen. These data indicate that tolerance to D1‐mediated effects on overt behavior is produced by chronic D1 receptor activation by SKF 83959. Tolerance is not necessarily accompanied by attenuation of the reinforcing effects of indirect dopaminergic stimulants like cocaine (supported by NIH DA03774).
Role of the central nucleus of the amygdala in hemodynamic responses to cocaine in conscious rats.
Authors: Ruhlman Melissa K , Watanabe Mari A. , Kucenas Sarah , Bowman Tamara A. , Knuepfer Mark M.
Published: June 2021

The central nucleus of the amygdala (CeA) has been shown to play an important role in sympathetic and behavioral responses to stress. We observed a greater vasoconstrictor response to cocaine in some rats (vascular responders or VR) compared to other rats (mixed responders or MR). We hypothesized that the CeA was responsible for greater increases in systemic vascular resistance (SVR) in response to cocaine and that angiotensin II (Ang) and corticotropin‐releasing factor (CRF) receptors were involved. Rats were instrumented for arterial pressure and cardiac output determination and for drug microinjection into the CeA. Rats were given cocaine (5 mg/kg, iv, twice daily, 4X) to determine their response pattern (VR or MR). Subsequently, rats were pretreated with bilateral microinjections (100 nl) of saline, muscimol (80 pmol), losartan (20 ng), or á‐helical‐CRF9‐41 (60 ng) followed by cocaine. Pretreatment with muscimol or losartan attenuated the increase in systemic vascular resistance (SVR) evoked by cocaine. Pretreatment with CRF antagonist prevented the difference in responsiveness between MR and VR by increasing the increase in SVR in MR. Our data suggests that the greater increases in SVR in vascular responders depend on neuronal transmission in the CeA and that Ang receptors facilitate and CRF receptors inhibit SVR responses to cocaine administration. Supported by USPHS RO1 DA13256 and DA0017371.
Lobeline attenuates morphine‐induced hyperactivity in rats
Authors: Miller Dennis K , Rodvelt Kelli R , Polston James E , Cunningham Colin S , Will Matthew J
Published: June 2021

Lobeline diminishes the behavioral and neurochemical effects of nicotine and amphetamines, and is considered a potential pharmacotherapy for stimulant abuse and addiction. Recently we determined that lobeline binds to µopioid receptors, inhibits the effects of µopioid receptor agonists in vitro, and decreases heroin self‐administration by rats. The present study determined the effect of lobeline (0.3‐1.0 mg/kg) on morphine (5‐10 mg/kg)‐induced changes in locomotor activity in rats after acute and repeated drug treatment. After acute treatment, neither morphine nor lobeline significantly altered locomotor activity, relative to rats administered only saline. With repeated treatment, morphine‐treated rats displayed hyperactivity, relative to saline‐treated rats. Importantly, the development of morphine‐induced hyperactivity was attenuated by lobeline in a dose‐dependent manner. In subsequent challenges to rats that had been treated repeatedly with the opiate, acute lobeline administration diminished morphine‐induced hyperactivity. Collectively, this line of research suggests that lobeline should be investigated as a novel treatment for opiate abuse and addiction.
Flow‐induced remodeling: interplay of local inflammation and vascular tone
Authors: Matlung Hanke , Bakker Erik N.T.P. , Bonta Peter , de Vries Carlie J , vanBavel Ed
Published: June 2021

We hypothesize that small artery remodeling is facilitated by inflammation but that smooth muscle cell tone sets its inward or outward direction.

Methods

Mouse mesenteric arcade arteries were ligated, resulting in low flow and high flow vessels. Immediate effects on tone were determined by in vivo microscopy. Structural remodeling was quantified after two days.

Results

Vessels exposed to high blood flow dilated, followed by outward remodeling. Low flow vessels constricted, followed by inward remodeling. Macrophage numbers increased 5‐fold in both groups, and remodeling was absent after macrophages depletion. Yet, the pattern of pro‐ and anti‐inflammatory cytokine expression was similar in high and low flow vessels. Low flow vessels under subsequent full dilation showed increased outward remodeling, as tested by a sequence of 1 day in vivo and 1 day in vitro study in a cannulation setup (13 ± 3% in inflamed arteries versus 6 ± 1% in control, n=5, p<0.05).

Conclusion

Altered blood flow is associated with an inflammatory response that facilitates remodeling; the direction is determined by vascular tone. Supported by the Netherlands Heart Foundation (NHS 2001T038).
Effect of Shear Stress on Connexin43 (Cx43) Protein Expression in Cultured Arteries
Authors: Berberich Kristen , Billig Janelle , Looft‐Wilson Robin
Published: June 2021

Shear stress, the frictional force of blood flow on vessel walls, induces artery dilation and remodeling. Low shear stress is associated with atherosclerosis. Cx43, a gap junction protein found in smooth muscle and/or endothelial cells, is involved in vascular cell‐to‐cell communication. Cx43 is up‐regulated in athero‐prone areas of arteries and by low shear stress in cultured endothelial cells, and genetically decreased Cx43 is associated with decreased atherosclerosis. We tested whether low vs. high shear stress would affect Cx43 expression in cultured arteries. This model results in inward remodeling with low shear stress, which is prevented by high shear stress in an eNOS‐dependent manner. Perfused, pressurized (80 mmHg) murine thoracodorsal arteries were cultured for 16.9‐19.9 hr with high physiological (65 ± 16 dynes/cm2, n=3 pooled) or low (2 ± 1 dynes/cm2, n=3 pooled) shear stress. Using western blotting, we found that differences in shear stress did not alter Cx43 protein (low vs. high: 1.035 : 1), whereas eNOS protein was less in low shear stress arteries (low vs. high: 0.591 : 1), suggesting endothelial dysfunction. These data indicate that despite pathological signs in low shear stress arteries, total Cx43 protein expression is unchanged. Support: APS Undergraduate Fellowship, NIH‐R15HL082647.
A Platform for Enhanced Contrast Ultrasound Targeted Delivery of Therapeutics
Authors: Burke Caitlin Wells , Price Richard J
Published: June 2021

Recently, there has been considerable interest in examining ultrasound‐mediated microbubble destruction as a method for noninvasive delivery of therapeutics. Here, we tested whether nanoparticle delivery could be markedly improved by ultrasound‐mediated destruction of composite delivery agents comprised of 100nm poly(lactide‐co‐glycolide) (PLAGA) nanoparticles that are adhered to 2‐4 μm diameter albumin shelled microbubbles, denoted here as microbubble nanoparticle composite agents (MNCAs). Fluorescently tagged PLAGA nanoparticles were delivered to mouse gracilis muscle via the ultrasonic destruction of circulating MNCAs. Cross‐sections of MNCA treated muscles were compared to muscles treated with microbubbles co‐administered with nanoparticles. We observed a 4‐fold increase in nanoparticle delivery in MNCA treated muscles over muscles treated with a co‐administration. These results suggest that binding the PLAGA nanoparticles to the albumin shell, as opposed to co‐administering them, significantly increases the delivery of nanoparticles to tissue. In preliminary studies using a tumor model in mice, we demonstrated that ultrasound mediated destruction of MNCAs resulted in nanoparticle delivery to tumor tissue. This further supports the utility of these MNCAs for a multitude of targeted drug delivery applications. Supported by the FUSF, the Hartwell Foundation, and NIH HL74082.
Seventieth Anniversary of Angiotensin, the Octapeptide with Two Names
Authors: Igic Rajko
Published: June 2021

In 1939, two research groups a great geographical distance apart independently discovered a novel pressor agent that was released by renin. The Argentine group named it hypertensin, and called its plasma protein substrate hypertensinogen. The US group named it angiotonin. Both names were used over the next two decades, even though Braun Menendez and Irvine Page, in 1958, suggested that the peptide should be named angiotensin. Eventually, this combined name became commonly accepted in order to overcome lasting linguistic confusion. Research scientists and physicians today acknowledge that the discoveries of both renin and angiotensin greatly improved our understanding of several diseases. Certainly medical practice profited significantly from the synthesis and application of numerous pharmacological agents that antagonize either the biosynthesis or pharmacological responses of endogenously generated angiotensin II. Ultimately, discovery of the renin‐angiotensin system enabled many studies that resulted in successful control of vascular disease.
Glut4 Increases with Prolonged Fasting in Northern Elephant Seals
Authors: Vazquez‐Medina Jose Pablo , Champagne Cory , Ortiz C Leo , Crocker Daniel E , Ortiz Rudy M
Published: June 2021

The northern elephant seal (Mirounga angustirostris) experiences periods of prolonged fasting (2‐3 months) as part of its natural life history during which plasma glucose concentrations decrease despite the maintenance of relatively low plasma insulin. Cellular glucose metabolism is regulated by the insulin‐dependent glucose transport protein, Glut 4. Mechanisms of cellular glucose metabolism regulation have not been examined in fasting seals. Therefore, the effects of prolonged fasting on Glut4 and insulin receptor protein content, and plasma glucose were examined. Muscle and blubber biopsies as well as plasma samples were obtained from two groups of northern elephant seal pups (n = 10/group) sampled during their post weaning fasting period: early (2 weeks) and late (6 to 8 weeks). Tissue samples were analyzed by Western blot for Glut4 and insulin receptor protein content. Circulating glucose levels decreased during the fast (9.8 ± 0.5 vs 8.0 ± 0.3 mM). In contrast, mean Glut4 levels increased in both muscle (31%) and blubber (26%) during the fast. Mean blubber insulin receptor content decreased 14% with the fast suggesting that the increase in Glut4 protein content is not insulin‐dependent during the fast in seals, which is consistent with the reduced circulating levels of insulin that we have reported for this species. Furthermore, the increase in Glut4 protein content may represent increased tissue utilization of glucose, which may partially explain the decrease in circulating levels. Funded by UC startup funds.
Differential Regulation of Ubiquitin ligases Atrogin‐1 and MuRF‐1 in Angiotensin II‐Mediated Skeletal Muscle Atrophy
Authors: Yoshida Tadashi , Semprun‐Prieto Laura , Sukhanov Sergiy , Delafontaine Patrick
Published: June 2021

Advanced congestive heart failure is associated with activation of the renin‐angiotensin system and skeletal muscle atrophy. Angiotensin II (Ang II) infusion in mice produces cachexia secondarily to increase of muscle proteolysis mediated by two E3 ubiquitin ligase Atrogin‐1 and MuRF‐1, and also decreased levels of circulating and skeletal muscle IGF‐1.

To determine mechanisms linking ubiquitin ligase expression and IGF‐1 signaling, time‐course dependent expression of Atrogin‐1, MuRF‐1, IGF‐1 and IGF‐1 receptor (IGF1R) was analyzed in skeletal muscles of Ang II infused mice. Expression of Atrogin‐1, MuRF‐1 and IGF1R were elevated one day after the initiation of Ang II‐infusion and were gradually decreased on day 4 and day 7. On the other hand, the expression of IGF‐1 was reduced on day 7. In skeletal muscles of mice overexpressing IGF‐1 specifically in skeletal muscle (MLC‐IGF‐1 mice), no significant reduction of skeletal muscle weight was observed after Ang II infusion and the basal and Ang II‐induced expression of Atrogin‐1 was significantly repressed. On the other hand, basal and Ang II‐induced expression of MuRF‐1 in skeletal muscles of MLC‐IGF‐1 mice was not different from WT animals.

These data demonstrate that the IGF‐1 prevention of Ang II induced skeletal muscle atrophy is mediated via the ability of IGF‐1 to repress Atrogin‐1 expression, rather than MuRF‐1 expression.

This work was supported by NIH Grant HL080682
Does Mitochondrial Uncoupling Generate More Mitochondria in Muscle?
Authors: Conley Kevin E. , Jubrias Sharon A , Shankland Eric , Amara Catherine E , Marcinek David J
Published: June 2021

Uncoupling of oxidative phosphorylation (low ATP/O2 or P/O) has been proposed to trigger the signaling pathway governing mitochondrial biogenesis. Here we test whether uncoupling accounts for variation in mitochondrial oxidative capacity (O2max) among muscles. Mitochondrial P/O and O2max were determined in a range of human muscles in vivo using a combination of magnetic resonance and optical spectroscopic tools. O2max was directly proportional to mitochondrial content in the four human muscles studied. These muscles ranged from well‐coupled (P/O =2.7+0.1, n=10, first dorsal interosseous of the hand, FDI) to 50% uncoupled (P/O =1.5+0.3, n=5, soleus) and showed a corresponding 2‐fold range of O2max. Similarly, O2max varied with the degree of uncoupling in hand muscle (FDI) between healthy adults and those uncoupled by pathology. Thus a proportionality is found between the extent of uncoupling and O2max among muscles and for a single muscle differing in coupling due to disease. These data support the hypothesis that uncoupling activates the signaling pathway governing mitochondrial biogenesis and may play an important role in the variation in mitochondrial content among muscles and with disease.
Chronic Glucose Infusion Increases Tubular Sodium Reabsorption and Renal Blood Flow in Dogs
Authors: Brands Michael W. , Cormican Michael , Banes‐Berceli Amy , Manhiani Marlina , Allen Ashlyn J , Sheppard Tuere A
Published: June 2021

It is not known whether hyperinsulinemia and/or hyperglycemia in metabolic syndrome contribute to the associated hypertension through chronic antinatriuretic actions. We tested this using chronic iv. glucose infusion to increase plasma insulin and glucose concentrations comparable to those measured in metabolic syndrome, and used 24 hr/day methods for measuring mean arterial pressure (MAP; DSI) and renal blood flow (RBF; Transonic). Blood glucose increased ~ 10 mg/dl over the 6‐day glucose infusion period, and plasma insulin increased from 28±4 to 45±12 µU/ml. Urinary sodium excretion averaged 70±8 mEq/d during control, decreased to 49±5 mEq/d on day 1 of glucose, and averaged 51±6 mEq/d over the 6 days. RBF averaged 123±17 ml/min during control, increased to 137±19 on day 1, and averaged 153±17 by day 6 of glucose. Plasma renin activity increased 3‐fold, and all variables returned to control values during recovery. MAP did not increase significantly. However, there was no tendency for MAP to decrease, eliminating pressure natriuresis as a mechanism for the sodium retention. This confirms our earlier report that glucose infusion causes sustained antinatriuresis in dogs, and the renal vasodilation indicates that tubular reabsorption is the mechanism. The renin and RBF responses are consistent with a role for the macula densa, but that and the reason why MAP did not increase require further study. HL56259, HL75625
The effects of sleep on the cardiovascular and the thermoregulatory systems – possible role for hypocretin
Authors: Schwimmer Hagit , Zeitzer Jamie M , Yanagisawa Masashi , Nishino Seiji , Stauss Herald M , Abboud Francois M , Mignot Emmanuel
Published: June 2021

The hypocretin neuropeptides modulate sleep and are anatomically connected to brain structures important for both sleep regulation and autonomic activity. We examined the role of hypocretins in autonomic regulation using a rat model in which hypocretin neurons are ablated. We simultaneously monitored core (Tc) and tail (Tt) temperatures, blood pressure (BP), ECG and locomotor activity. We analyzed the daily patterns, relative contribution of sleep and circadian components, transitional changes, baroreceptor reflex, and heart rate (HR) and BP variability.

Tc and HR are affected by both sleep and time of day, but BP is exclusively affected by sleep. BP and HR both have specific, reproducible patterns of change during state transitions. Tt preceded the actual transitions, implying peripheral early starting of the transition. The loss of hypocretin neurons caused a sleep state‐dependent decrease in BP. The relative contributions of sleep and time‐of‐day effects were differential based on the specific variable being examined. Hypocretins appear to be involved in mediating the effects of sleep on BP and vasoconstriction of skin blood vessels.
Brain salt sensitivity in mice with LVH is enhanced via Rho‐kinase pathway through ENaC activation
Authors: ITO KOJI , HIROOKA YOSHITAKA , SUNAGAWA KENJI
Published: June 2021

Salt intake predisposes patients with left ventricular hypertrophy (LVH) to heart failure. We hypothesized that brain Na‐sensitivity increased in patients with LVH. To examine the mechanism of Na‐sensitivity associated with LVH, we performed aortic banding (AB) to produce mice with LVH. Four weeks after AB, 24‐h urinary catecholamine excretion (U‐CA) tended to increase in AB compared with sham‐operated mice (Sham). AB induced an increase in the LV wall thickness without LV dysfunction. AB was then fed either a high‐salt diet (ABH) or a regular‐salt diet (ABR) for 4 weeks. LV dysfunction and U‐CA increased in ABH compared with ABR. We then examined brain Na‐sensitivity. Intracerebroventricular (ICV) infusion of high‐Na artificial cerebrospinal fluid into AB and Sham increased U‐CA, arterial pressure, and heart rate to a greater extent in AB than in Sham. Infusion (ICV) of an epithelial Na channel (ENaC) blocker into ABH for 4 weeks significantly lowered U‐CA and improved LV function. Infusion of a Rho‐kinase inhibitor also attenuated the salt‐induced sympathetic hyperactivation and LV dysfunction in ABH. The levels of phosphorylated‐moesin, a substrate of Rho‐kinase, were significantly greater in AB than in Sham. These results suggest that increased brain Na‐sensitivity, due to the activation of ENaC via Rho‐kinase contributes to salt‐induced sympathetic hyperactivation and LV dysfunction in mice with LVH.
Baroreflex influence on arterial pressure and heart rate in conscious mice
Authors: Fazan Rubens , Rodrigues Fernanda Luciano , Oliveira Mauro , Salgado Helio Cesar , Dias da Silva Valdo Jose
Published: June 2021

The goal of this study was to determine the baroreflex influence on arterial pressure and pulse intervals (PI) in conscious mice. Male C57BL mice were subjected to sinoaortic denervation (SAD, n=14) or sham surgery (n=17), and catheters were placed into the femoral artery and jugular vein. 24 h or 5 days after surgery arterial pressure was continuously recorded for 30 min in the conscious mice. Efficacy of SAD was determined at the end of pressure recording by i.v. administration of phenylephrine and sodium nitroprusside. The standard deviation of systolic arterial pressure (SAP) measurements and the square root of the mean squared differences of successive values of PI were used as measurements of SAP and PI variability, respectively. Baroreceptor denervated mice showed higher SAP at both 24 h (144±8 vs. 125±4 mmHg) and 5 days (152±3 vs. 135±3 mmHg) after SAD. Variability of SAP was also markedly increased in SAD mice as compared with sham‐operated controls (8.0±1.3 vs. 4.9±0.8 and 9.8±1.1 vs. 6.4±0.6 mmHg, 24 h and 5 days after SAD). PI was found similar among the groups studied (119±8 vs. 115±8 and 105±4 vs. 94±3 ms, 24 h and 5 days after SAD). Variability of PI was less in mice 24 h after SAD (0.90±0.06 ms) compared to that observed in mice subjected to sham surgery (1.28±0.11 ms). Interestingly PI variability did not differ in SAD vs. sham‐operated mice 5 days post surgery (1.87±0.27 and 1.82±0.19 ms) (Support: FAPESP, CNPq).
Assessment of heart rate variability during different sleep stages in rats: analysis of non‐stationarities
Authors: Tobaldini Eleonora , Magagnin Valentina , Porta Alberto , Montano Nicola , Kocsis Bernat
Published: June 2021

An increasing interest has been focused on the assessment of autonomic regulation during sleep by means of heart rate variability (HRV) analysis. The common tools to analyze HRV require signal stationarity, but no studies addressed this problem during sleep. Aim of our study was to evaluate the prevalence of non‐stationarities on HRV series during different sleep stages.

We recorded ECG in rats for 8 hours with episodes of wake (W), slow wave sleep (SWS) and REM sleep and evaluated the stationarity of HRV series of lengths ranging from 100 to 300 beats (with steps of 50). For each series, 8 sub‐sequences of 50 samples were randomly selected and checked if mean and variance remained constant over all the patterns by means of analysis of variance (F‐test) and Bartlett test respectively.

We found increasing percentages of non‐stationarity (from 60 to 100%) with series length increasing from 100 to 200 beats, while all the series longer than 200 were totally non‐stationary. The percentage of non‐stationarity were similar between W, SWS and REM. In conclusion, our data suggest to use time series shorter than 200 beats to reduce non stationarities when assessing HRV during sleep in rats. Moreover, the sources on non‐stationarity may be different in different sleep‐wake stages, being prevalently related to motor activity during W and SWS and more dependent upon sympathetic‐parasympathetic shifts during REM sleep.
ROLE OF ENDOTHELIN IN IMPAIRED RESPONSES OF CEREBRAL ARTERIOLES DURING TYPE 1 DIABETES MELLITUS
Authors: Arrick Denise Mary , Sharpe Glenda , Sun Hong , Mayhan William G
Published: June 2021

Previous studies have suggested that endothelin‐1 may contribute to vascular abnormalities during a variety of disease states, including Type 1 diabetes mellitus. Endothelin‐1 may contribute to structural and functional abnormalities of the blood vessels, and may also regulate the expression of other growth factors and cytokines to influence vascular function. However, there is a lack of information regarding the precise role of endothelin‐1 in altered NOS‐dependent responses of cerebral arterioles during Type 1 diabetes. Thus, our goal was to determine whether acute inhibition of endothelin‐1 receptors (BQ‐123) could influence NOS‐dependent responses of cerebral arterioles in diabetic rats. We measured diameter of pial arterioles in nondiabetic and diabetic (STZ; 50 mg/kg) rats in response to eNOS‐ and nNOS‐dependent (ADP and NMDA) and ‐independent (nitroglycerin) agonists before and during treatment with BQ‐123. In addition, we measured superoxide production by cerebral cortex tissue obtained from nondiabetic and diabetic rats. We found that eNOS‐ and nNOS‐dependent dilation of pial arterioles was impaired in diabetic compared to nondiabetic rats. In addition, treatment with BQ‐123 restored impaired responses of cerebral arterioles in diabetic rats towards that observed in nondiabetic rats. Further the production of superoxide anion by cortex tissue was increased in diabetic rats when compared to nondiabetic rats. We suggest that endothelin‐1 may contribute to impaired responses of cerebral arterioles during Type 1 diabetes. We speculate that endothelin receptor antagonism may be a potential therapeutic tool for the treatment of cerebrovascular dysfunction observed in diabetic subjects.
Nox4 NADPH oxidase mediates oxidative stress and apoptosis caused by TNF‐alpha in cerebral vascular endothelial cells.
Authors: Basuroy Shyamali , Bhattacharya Sujoy , Leffler Charles W , Parfenova Helena
Published: June 2021

Inflammatory brain disease may damage cerebral vascular endothelium leading to cerebral blood flow dysregulation. The pro‐inflammatory cytokine TNFα causes oxidative stress and apoptosis in cerebral microvascular endothelial cells (CMVEC) from newborn pigs. We investigated contribution of NADPH oxidase (Nox family), a cellular source of superoxide (O2·−) to the endothelial inflammatory response. NADPH oxidase inhibitors (DPI and apocynin) greatly reduced TNFα‐evoked O2·− generation and apoptosis. Among the Nox family members, Nox2 and Nox4 are expressed in CMVEC. Nox4 siRNA knockdown completely blocked oxidative stress and apoptosis caused by TNFα, while Nox2 siRNA knockdown only partially (by 20‐30%) attenuated apoptosis. Nox4 is co‐localized with HO‐2, the constitutive isoform of heme oxygenase (HO), which is critical for endothelial protection against TNFα toxicity. The product of HO activity, carbon monoxide (CO), inhibited TNFα induced Nox4 activity and apoptosis. We conclude that Nox4 is the primary source of inflammation‐ and TNFα‐induced oxidative stress leading to apoptosis in brain endothelial cells. The ability of CO to inhibit Nox4 activity, taken together with close intracellular compartmentalization of Nox4 and HO‐2 in cerebral vascular endothelium, may contribute to HO‐2 cytoprotection against inflammatory cerebrovascular disease.
The importance of aldosterone suppression in the restoration of cerebrovascular myogenic function in SHRsp during post stroke Captopril and Losartan treatment
Authors: Smeda John Stanislaw , Daneshtalab Noriko
Published: June 2021

Treatment of Kyoto Wistar stroke prone spontaneously hypertensive rats (SHRsp) with Captopril (CAP) or Losartan (LOS) after hemorrhagic stroke (HS) restores pressure dependent constriction (PDC) in middle cerebral arteries (MCAs) . We assessed the importance of aldosterone (ALD) suppression during both treatments. Plasma ALD was elevated in SHRsp with HS over prestroke levels (3.9 ± 0.8 nM vs 0.15 ± 0.09 nM). SHRsp with HS were treated orally with 50mg/kg/day CAP or 35 mg/kg/day LOS for 28 days. During the last 10 days of treatment ALD (0.66 μg/hr) or vehicle was infused via an osmotic pump . CAP and LOS treatment suppressed plasma ALD (0.23 ± 0.07 and 0.075 ± 0.044 nM respectively), whereas supplementation elevated ALD (6.27±1.75 and 4.49 ± 0.80 nM respectively). ALD supplementation did not alter BP. After 28 days of CAP or LOS treatment, MCAs from SHRsp with HS (studied using a pressure myograph) regained PDC and the ability to constrict in response to protein kinase C activation (1μM phorbol dibutyrate) and elevated [K+]o depolarization. ALD supplementation prevented these changes in CAP but not LOS treated SHRsp. Elevation in plasma ALD enhance the deterioration of myogenic function. We believe that poststroke treatment with LOS (vs CAP) promotes systemic beneficial effects that permit the restoration of cerebrovascular function even under conditions of where plasma ALD is elevated.
Detection of brain‐derived circulating endothelial cells in peripheral blood of newborn infants with cerebrovascular disorders
Authors: Pourcyrous Massroor , Tcheranova Dilyara , Basuroy Shyamali , Leffler Charles W , Parfenova Helena
Published: June 2021

Cerebrovascular disorders in neonates may contribute to long‐term neurological complications. Early detection of cerebrovascular damage is important for clinical management and prognosis. However, early diagnosis of cerebrovascular injury in clinical settings remains challenging. Based on our data, seizures are accompanied by the early appearance of circulating endothelial cells (CECs) of brain origin (BCECs) in blood of newborn piglets that coincides with the late loss of endothelial‐dependent regulation of cerebral blood flow. We hypothesized that BCECs of human neonates with cerebrovascular disorders could provide a non‐invasive diagnostic approach for detecting cerebrovascular injury. Newborn infants with seizures, asphyxia, intraventricular hemorrhage and infection, which may cause cerebrovascular injury, were included in our study. Blood samples were collected from neonates. BCECs were immunodetected by co‐expression of endothelial‐specific (CD146 and CD31) and brain‐specific (GLUT‐1) antigens. In control infants BCECs were not detectable. Conversely, BCECs were detected in preterm infants with sustained seizures. These data suggest that BCECs may be helpful in clinical setting when acting within a small therapeutic window is critical for prophylactic/rescue intervention to improve long‐term neurological outcome in infants with cerebrovascular insults.
Bumetanide and HOE642 administered after initiation of rat middle cerebral artery occlusion effectively reduce rat brain Na uptake and infarct
Authors: Chen Yi‐Je , Anderson Steven E. , O'Donnell Martha E.
Published: June 2021

Increased brain Na uptake across an intact blood‐brain barrier (BBB) contributes to cerebral edema formation in the early hours of ischemic stroke. We have shown previously that a luminal BBB Na‐K‐Cl cotransporter and Na/H exchanger are stimulated by ischemic factors and that both edema and infarct induced by middle cerebral artery occlusion (MCAO) are reduced by i.v. bumetanide or HOE642, inhibitors of the cotransporter and exchanger, respectively. The present study was conducted to determine whether bumetanide and HOE642 reduce the brain Na uptake that underlies edema in ischemic stroke and further, whether they are effective when given after the onset of ischemia. Rats were given bumetanide (30 mg/kg), HOE642 (30 mg/kg) or vehicle i.v. 20 min before, or 1 or 2 hr after initiation of left MCAO. Localized 23Na magnetic resonance spectroscopy with the shift reagent DyTTHA was used to assess total and extravascular brain [Na] in selected regions of interest during up to 5 hr of MCAO. The ipsilateral/contralateral brain ratios of both total [Na] and extravascular [Na] increased linearly following induction of ischemia. Bumetanide and HOE642 significantly reduced brain Na uptake and infarct when given before or after the start of MCAO. Our findings suggest that inhibition of the Na‐K‐Cl cotransporter and Na/H exchanger, even 2 hr after the start of ischemia, effectively reduces brain Na uptake and infarct.

Supported by NINDS
Hypoxic Exercise Training Suppresses Oxidative Stress‐induced Lymphocyte Apoptosis
Authors: Chen Wan‐Ling , Wang Jong‐Shyan
Published: June 2021

This study investigates how hypoxic exercise training affects oxidative stress‐induced lymphocyte apoptosis and further explores its underlying mechanisms. Twelve sedentary males were trained on a bicycle ergometer at about 60%VO2max under 15% O2 air condition for 20 minutes per day, 5 days per week for 4 weeks. Sublethal oxidative stress was administered by treating the lymphocytes with 200μM H2O2, to closely approximate in vivo pro‐oxidative conditions. Our results demonstrated that before the training, strenuous exercise enhanced H2O2‐induced phosphotidyl serine exposure of lymphocyte, which was accompanied by a decline in mitochondrial transmembrane potential (MTP) and increases in active‐form caspase 3, 8 and 9 contents in lymphocyte. However, 4 weeks of hypoxic exercise training attenuated H2O2‐induced lymphocyte caspase activation and apoptotic response during strenuous exercise. We conclude that although strenuous exercise can promote oxidative stress‐induced lymphocyte apoptosis by declining MTP and activating intrinsic and extrinsic caspases, long‐term hypoxic exercise training suppresses the acute exercise effect on oxidative stress‐induced lymphocyte apoptosis.
ANGIOTENSIN II INDUCED APOPTOSIS IN ADULT CARDIOMYOCYTE IS SUPPRESSED BY ALL TRANS‐RETINOIC ACID
Authors: Sharma Anita K , Thangirala Sudha , Dhingra Sanjiv , Ludke Ana , Bajaj Anju , Singal Pawan K.
Published: June 2021

Circulatory levels of Angiotensin II (Ang II) and oxidative stress are increased in heart failure and both of these conditions are known to induce apoptosis. Vitamin A (retinol) is an important antioxidant and its uptake in the heart from plasma is increased in heart failure. Since vitamin A is metabolized to different bioactive molecules, most notably all trans‐retinoic acid (RA), we examined significance of RA in Ang II induced apoptosis in isolated adult cardiac myocytes. Ang II (10−9 M) caused a significant increase in myocytes apoptosis and pre‐treatment with RA (10−7 M) attenuated the morphological and biochemical markers of apoptosis. An increase in Bax / Bcl‐xl ratio by Ang II was prevented by RA. Ang II induced expression of phosphorylated ERK and JNK proteins was also modulated by RA. There was a moderate reduction in mRNA expression of c‐jun and c‐fos by RA treatment. Ang II treatment increased the levels of RXRs and pre‐treatment with RA lead to a reduction in the RXR levels and up‐ regulation of RAR receptors. RARs work in conjunction with RXRs and the present study indicates that low concentration of RA may activate only RAR receptors in cardiac myocytes in the presence of Ang II. The inhibitory effect of RA on the Ang II induced apoptosis in the cardiac myocytes is, thus, through a RAR‐dependent pathway. The results suggest that the interaction between RA and Ang II appears to be more complex than simple suppression of Ang II signaling (Supported by CIHR).
Role of Na+/H+ Exchange (NHE) in hypoxia‐induced pulmonary arterial smooth muscle cell (PASMC) growth and migration
Authors: Undem Clark , Walker Jasmine , Shimoda Larissa A
Published: June 2021

In many lung diseases, chronic hypoxia (CH) causes pulmonary hypertension resulting in part from vascular remodeling due to growth/migration of PASMCs. The mechanisms involved in this process are unresolved, but a role for NHE activity has been suggested. We examined whether NHE activity was required for hypoxia‐induced PASMC growth/migration. Equal numbers of PASMCs from rats exposed to normoxia or CH (10% O2; 3 wk) were plated into 96 well plates (proliferation) or onto transwell filters (migration). In some experiments, cells were exposed to hypoxia (4 or 1% O2) ex vivo. PASMCs were cultured with or without the NHE inhibitor, ethyl isopropyl amiloride (EIPA; 10‐5 M). For proliferation, cells were cultured for 48 hr before addition of BrdU for 24 hrs. ELISA for BrdU incorporation showed that CH and ex vivo hypoxia induced PASMC proliferation. EIPA reduced both basal and hypoxia‐induced growth. For migration, PASMCs were cultured on filters for 24 hr, fixed and Coomasie stained. Cells on the transparent filters were imaged (total), the upper side of the filter scraped and images of migrated cells (bottom of filter) obtained. The percent of migrated cells was greater in cells exposed to CH and hypoxia ex vivo. EIPA reduced migration induced by CH and 4% O2. These data suggest that NHE activity modulates hypoxia‐induced PASMC growth and migration and may contribute to increased muscularization of small pulmonary arteries.
Ozone and allergen exposure exacerbates the role of 5‐HT heteroreceptors in cholinergic mediated airway smooth muscle contraction in a non‐human primate model
Authors: Moore Brian Dean , Schelegle Edward S. , Hyde Dallas , Miller Lisa , Wong Emily , Frelinger Jessica
Published: June 2021

Exposure of adolescent rhesus monkeys to ozone (O3) and/or house dust mite allergen (HDMA) has been shown to contribute to post natal remodeling of the neural, muscular and immunological components of the airway. Similar exposure regimens have associated O3 and HDMA with airway hyper responsiveness. One possible mechanism contributing to the increase in contractility has been attributed to the post‐ganglionic, pre‐synaptic influence of serotonin (5‐HT) on cholinergic mediated airway smooth muscle contraction. Twenty‐four adolescent rhesus monkeys were exposed to 11 episodes of filtered air (FA), HDMA aerosol, O3, or HDMA + O3 (5 days each followed by 9 days of FA). Ozone was delivered for 8 h/day at 0.5 ppm. All monkeys were sensitized to HDMA and were exposed to HDMA aerosol for 2 h/day on days 3‐5 of either FA (n = 6) or O3 (n = 6) exposure. Necropsies were performed at one year of age and 6 conducting airway rings were harvested for evaluation by electrical field stimulation. All four treatment groups exhibited an increase in contractility when exposed to increasing concentrations of 5‐HT (1uM‐100uM). The O3 treated group exhibited the greatest increase in contraction tension in response to 5‐HT (433% of control). Further evaluation of contractility utilizing specific 5‐HT receptor agonists revealed that the 5‐HT3 receptor subtype played a prominent role in exacerbating the cholinergic mediated contraction in the O3 treated group. The influence of 5‐HT3 receptors was also substantiated due to the attenuation of 5‐HT modulated contraction with the addition of a 5‐HT3 receptor antagonist.
Role of Mitochondria in SR Calcium Buffering in Human Airway Smooth Muscle
Authors: Yang Binxia , Thompson Michael , Prakash Y S , Pabelick Christina
Published: June 2021

Sarcoplasmic reticulum (SR) Ca2+ release and reuptake are important mechanisms in airway smooth muscle (ASM) intracellular Ca2+ [Ca2+]i regulation. In other tissues, there is increasing evidence for a role of mitochondria in [Ca2+]i buffering, especially following SR Ca2+ release. Mitochondrial buffering may also influence Ca2+ influx. The purpose of the present study was to examine the role of mitochondria in [Ca2+]i buffering in human ASM. Cells were loaded with fura‐2 and exposed to 10 µM histamine in "0" Ca2+ HBSS containing 1mM lanthanum and 1µM nifedipine (to block Ca2+ influx/efflux) and in the additional presence of 1µM RU360 (mitochondrial Ca2+ uniporter inhibitor) or 1µM CGP37157 (CGP; mitochondrial Na+/Ca2+ exchange inhibitor). Compared to controls, peak [Ca2+]i levels were increased by 30% in the presence of CGP, while RU360 had not effect. Both CGP and RU360 significantly increased store‐operated Ca2+ entry. In cells co‐loaded with fura‐2 and rhod‐2 (mitochondrial Ca2+ indicator), exposure to 5 µM caffeine showed instantaneous SR Ca2+ release followed by an increase in [Ca2+]mito. Exposure to 1 µM ACh resulted in ACh‐induced [Ca2+]i oscillations that were reflected by mitochondria (but with a time delay). In ASM cells co‐labeled for mitochondria (MitoTracker) and SR (fluorescent ryanodine) migration of mitochondria towards SR was observed upon exposure to ACh or cyclopiazonic acid. This migration was completely inhibited by phalloidin (actin inhibitor). These data demonstrate an important role of mitochondria in [Ca2+]i buffering in ASM.

Supported by NIH grant RR024150, and the Flight Attendants Medical Research Institute (FAMRI). Additional funding from the Department of Anesthesiology, Mayo Clinic.
Abnormal lung phenotype in Rab38‐deficient rats, rodent models of Hermansky‐Pudlak syndrome
Authors: Osanai Kazuhiro , Kobayashi Makoto , Higuchi Junko , Tsuchihara Katsuma , Iguchi Masaharu , Huang Jongsu , Toga Hirohisa
Published: June 2021

Several Long Evans rat substrains carrying the phenotype of oculocutaneous albinism and bleeding diathesis are considered as rat model of the Hermansky‐Pudlak syndrome (HPS). The mutation responsible for the phenotype (Ruby) was identified as a point mutation in the initiation codon of Rab38 small GTPase. We investigated the lung phenotype of Long Evans Cinnamon rats. The lung histology revealed uniform enlargement of distal airway space, and alveolar type II cells contained markedly enlarged lamellar bodies. Surfactant phosphatidylcholine (PC) and surfactant protein B were increased in the lung tissue and lamellar body fraction, but not in alveolar lumen. Surfactant protein A levels were decreased in the lung tissue and alveolar lumen. Isolated alveolar type II cells showed aberrant secretory pattern of newly synthesized [3H]PC, i.e. decreased basal secretion and remarkably amplified agonist‐induced secretion. We constructed recombinant adenovirus vector expressing Rab38. The agonist‐induced [3H]PC secretion in Rab38‐deficient cells infected with Ad‐Rab38 was decreased close to that in Rab38+/+ cells. Thus, Rab38‐deficient rats show alveolar structural deformity and aberrant lung surfactant homeostasis with altered alveolar type II cell morphology. These results suggest that Rab38 deficiency develops a complication of lung disease in the phenotype of HPS.
Role of γ‐glutamyl transpeptidase in redox regulation of K+ channel remodeling in heart failure
Authors: Zheng Ming‐Qi , Tang Kang , Xie Bin , Zimmerman Matthew C , Rozanski George J
Published: June 2021

γ‐Glutamyl transpeptidase (γGT) regulates cellular GSH levels in response to extracellular GSH (GSHo). The objective of this study was to identify the role of γGT in reversing K+ channel remodeling in heart failure, which was induced in rats by chronic myocardial infarction (MI). Assays of tissue extracts from MI hearts showed marked increases in γGT activity, protein and mRNA in left ventricle and septum compared with sham hearts. Voltage‐clamp studies of ventricular myocytes from MI hearts showed that down‐regulation of transient outward K+ current (Ito) was reversed after 4‐5 h by 10 mM GSHo or N‐acetylcysteine (NACo). The effect of GSHo but not NACo was blocked by γGT inhibitors acivicin or S‐hexyl‐GSH. Inhibition of GSH synthesis by buthionine sulfoximine did not prevent up‐regulation of Ito by GSHo, but an SOD mimetic (MnTPyP) and catalase blocked recovery of Ito by GSHo. Confocal microscopy using the fluorogenic dye DCFH showed that GSHo increased ROS generation by MI myocytes and to a lesser extent in sham myocytes. Moreover, up‐regulation of Ito by GSHo was blocked by inhibitors of tyrosine kinase (genistein, lavendustin A, AG1024) or thioredoxin reductase (auranofin, 13‐cis‐retinoic acid). These data suggest that GSHo elicits γGT‐ and ROS‐dependent transactivation of tyrosine kinase signaling which up‐regulates K+ channel activity/expression via redox mechanisms.

Supported by NIH grant HL066446.
Oral Administration of EGCG, a Green Tea Antioxidant, Reduces Growth and Capillary Density of Melanoma but does not affect those of the Heart and Skeletal Muscles in Mice
Authors: Gu Jian‐Wei , Tucker Kevan B , Young Emily , Wells Jeremy , Chawla Simran
Published: June 2021

We previously reported that EGCG, a green tea antioxidant, inhibits tumor growth and angiogenesis of breast cancer in mice. However, it is not clear whether EGCG exerts an anti‐angiogenic effect on normal body tissues while inhibiting tumor angiogenesis. The present study evaluates the effects of EGCG on melanoma angiogenesis and growth, capillary density (CD) in the heart and skeletal muscles of mice. Six wk old male mice (C57BL/6J) were given EGCG at 50‐100 mg/kg/d (25 mg/50 ml in drinking water) for 4 wks. Control mice received drinking water only. In the 2nd wk, 10^6 B16F10 (mouse melanoma) cells were injected in the right proximal dorsal. In the end, the tumor, heart, and limb muscles were isolated for measuring tumor size, CD using CD31 immunohistochemistry, and VEGF expression using ELISA. EGCG significantly reduced tumor weight over the control (2.9±0.5 vs. 5.9±1.8 g; n=6; P<0.05), CD (117±21 vs. 167±25; P<0.01), and VEGF expression (32.6±1.6 vs. 41.5±2.3 pg/mg; P<0.01) of the melanomas in mice. EGCG had no effect on CD in the heart (3270±162 vs. 3103±226 #/mm^2) and limb muscles (370±55 vs. 381±44 #/mm^2), compared to the control (P>0.05). EGCG did not affect VEGF expression in the heart and limb muscles, the body weight and heart weight. These findings support the hypothesis that EGCG as an antioxidant inhibits tumor angiogenesis and tumor growth but does not affect the normal tissue CD and growth. (HL51971 & AA013821)
Calcium‐Sensing Receptor Activation In Vivo Decreases Plasma Renin Activity
Authors: Atchison Douglas K. , Beierwaltes William H.
Published: June 2021

The calcium‐sensing receptor (CaR) transmits changes in extracellular calcium to changes in intracellular signaling and hormonal secretion. The CaR is expressed in many different cell types that indirectly or directly regulate renin secretion including endothelial and vascular smooth muscle cells, as well as the renin‐secreting juxtaglomerular (JG) cells. We have demonstrated that Sensipar, a CaR‐activating calcimimetic, decreases renin release in vitro in primary cultures of JG cells. However, the response to CaR activation on renin secretion in vivo is unknown. As such, we hypothesized that activation of the CaR with Sensipar in vivo would also decrease renin secretion in anesthetized, male Sprague‐Dawley rats. We infused Sensipar i.v. into anesthetized rats at a dose of 60 mg/kg/hr over 60 min. Blood pressure and renal blood flow remained constant at 101±3 mm Hg and 6.21±0.39 ml/min/g kidney weight, respectively, during the infusion of Sensipar. Basal plasma renin activity (PRA) was 15.42 ± 4.41 ngAngI/ml/hr. Sensipar decreased PRA by 58% to 6.53 ± 1.88 ngAngI/ml/hr (p<0.05, n=7). While our result can not necessarily be attributed to the JG cell‐expressed CaR, we conclude that CaR activation inhibits renin secretion in vivo in the absence of changes in renal hemodynamics or blood pressure.
Prolactin family regulate vascular tone through the modulation of nitric oxide production
Authors: Gonzalez Carmen , Cuevas Pedro Martinez , Jothar Lucia Martinez , Manzo Pilar Larraga , Salcedo Jimena Velarde
Published: June 2021

Prolactin (PRL) family, include, placental lactogen (PL), growth hormone (GH) and prolactin, have been associated with reproduction, lactation, differentiation and angiogenesis. However, little is known about their effects upon the vasculature. The present study was designed to determine the regulatory effects that PL, GH and PRL exert on the vascular tone and, the association with endothelial nitric oxide (NO) production, a free radical that promotes vasodilation. In this study we used isolated rat aortic rings sub maximally precontracted with phenylephrine and, treated with known vasoactive substances, acetylcholine (ACh) to elicit NO‐mediated relaxation or an endothelium‐independent relaxation NO donor, as controls. PL and GH, promoted only vasodilation‐endothelium dependent, directly associated with an increase of NO production, these actions were comparable with ACh‐induce relaxation. PRL stimulated vasoconstriction and did not modify the basal levels of NO. We are first to report, opposite actions of PL and GH with respect to PRL, in this vascular bed. Further investigation are underway in our laboratory to fully know the role of PL, GH and PRL upon vascular endothelium, which may contribute to the understanding and control of cardiovascular pathologies, like coronary ischemia, that colud resolve through stimulation of vasodilaton. Supported by PROMEP /103.5/07/2574 and CONACyT 84576.