Tension Recording Research Articles

Vasodilation promoted by (E,E)-farnesol involving ion channels in human umbilical arteries

Background(E,E)-farnesol is a sesquiterpene alcohol derived from plants and animals that exhibits pharmacological properties in the cardiovascular system. However, its effects on human umbilical vessels remain unknown. PurposeThus, this study aims to characterize the vasodilatory effect of (E,E)-farnesol in human umbilical arteries (HUA). Study designThe tissue is obtained from pregnant women over 18 years of age, normotensive, and without prepartum complications. After collected, the tissue was segmented and dissected to remove Wharton's jelly and obtain the umbilical arteries segments. MethodsHUA segments were isolated and sectioned into rings that were subjected to isometric tension recordings in an organ bath. Results(E,E)-farnesol (1 μmol/L to 1 mmol/L) promoted vasodilatory effect in HUA preparations, affecting basal tone, and inhibiting the electromechanical coupling induced by KCl 60 mmol/L with greater potency (EC50 225.3 μmol/L) than the pharmacomechanical coupling induced by 5-HT 10 μmol/L (EC50 363.5 μmol/L). In the absence of extracellular calcium, pharmacomechanical coupling was also abolished, and contractions induced by CaCl2 or BaCl2 were attenuated by (E,E)-farnesol indicating a possible direct inhibition of L-type VOCC as a mechanism of the vasodilatory effect. The vasodilator efficacy of (E,E)-farnesol on reduction of vasocontraction induced by the presence of tetraethylammonium (1 or 10 mmol/L), 4-aminopyridine (1 mmol/L) and glibenclamide (10 μmol/L) suggesting a possible influence of different potassium channels (BKCa, KV and KATP). ConclusionThese results suggest that (E,E)-farnesol may be a promising pharmacological candidate for obstetric hypertensive disorders.

O105 The impact of experimental hyperchloraemic acidosis on porcine isolated visceral arterial contractility

Abstract Introduction Hyperchloraemic acidosis is known to be associated with impaired renal function in post-operative patients. We have experimentally investigated whether elevation in chloride and hydrogen ions have the potential to negatively impact the porcine renal vasculature. Methods Porcine renal (RA) and mesenteric (MA) arteries were placed in Krebs-Henseleit solution (K-H), gassed with 95%O2/5%CO2, and prepared for isometric tension recordings. 60mM KCl was used for standardized contractions and preparations were then exposed to the thromboxane-mimetic U46619, followed 6-18mM of either NaCl or Na Gluconate (NaGlu). Preparations were also exposed to increasing concentrations of noradrenaline in normal K-H (pH 7.4) and K-H pH 7.2. Results U46619 (10-20nM) produced stable contractions in RA and MA equivalent to 50% of that to 60mM KCl. 18mM NaCl caused a further contraction in RA (19.8±4.2%, n=9, p < 0.01), while 18mM NaGlu (3.8±4.4%, n=9) did not. Neither 6-18mM NaCl nor 6-18mM NaGlu caused responses in MA (< 4%, n=6). Noradrenaline produced concentration-dependent contractions in MA in normal K-H solution (logEC50 5.43±0.11: Max’ 226.8±24.6% 60mM KCl, n=6) that were significantly reduced (p < 0.05) in K-H pH 7.2 (logEC50 5.13±0.02: Max’ 174.4.8±3.3%, 60mM KCl, n=6). In contrast, in the RA noradrenaline contractions (logEC50 5.80±0.08: Max’ 162.8±12.0% 60mM KCl, n=11) were not affected (p > 0.05) by K-H solution pH 7.2 (logEC50 5.71±0.07: Max’ 177.8±15.3% 60mM KCl, n=11). Conclusion Elevation of chloride ions (experimental hyperchloraemia) selectively constricts porcine renal blood vessels, while corresponding elevation in hydrogen ions (acidosis) selectively dilates the mesenteric vasculature.

O100 The effect of acidosis on contractility induced in porcine splanchnic arteries by clonidine or noradrenaline

Abstract Introduction Clonidine, through its agonist action on central α2-adrenoceptors, is increasingly being used to induce sedation in critically ill patients with persistent acidosis and impaired renal function. Since it is also known to exert cardiovascular effects via peripheral α2-adrenoceptors, we compared its vasoconstrictor activity in porcine isolated arteries at different pH, to that produced by noradrenaline. Methods Isometric tension recordings of porcine isolated mesenteric, splenic and renal arteries (2mm internal diameter) were conducted in modified Krebs-Henseleit solution containing 105mM chloride ions maintained at pH 7.2 and 7.4 (modification of bicarbonate and chloride ions with gluconate ions). The potency of clonidine and noradrenaline was assessed by the pD2 (logarithm of concentration causing 50% of maximum response). Results Clonidine elicited concentration-dependent contractions in the renal artery (pD2 - 7.25±0.09 and 7.10±0.10, n=9) and splenic artery (pD2 - 6.81±0.09 and 7.02±0.06, n=8) that were not altered by a reduction in pH from 7.4 to 7.2 (p >0.05 paired Student's t-test). Clonidine failed to elicit consistent responses in the mesenteric artery (< 10% 60mM KCl). In contrast, the maximum response and potency to noradrenaline in the mesenteric artery (226.6±24.6% and pD2 5.43±0.11, n=6) was significantly reduced (p <0.05) by pH 7.2 (174.4±13.3% and pD2 5.13±0.11, n=6). Responses to noradrenaline in the renal and splenic artery were not affected by changes in pH. Conclusion Acidosis impairs the peripheral vascular actions of the non-selective α-adrenoceptor agonist noradrenaline more than those elicited by the selective α2-adrenoceptor agonist clonidine.

Involvement of beta3-adrenergic receptors in relaxation mediated by nitric oxide in chicken basilar artery

The response of basilar arteries to noradrenaline varies among many animal species, but remains little studied in poultry. Accordingly, we aimed to characterize the adrenergic receptor (AR) subtypes that modulate vascular response in basilar arteries in the chicken, with isometric recording of arterial ring tension using an organ bath. We demonstrated the presence of both alpha and beta (α and β) receptor subtypes through evaluating the response to noradrenaline, with and without a range of β-AR and α-AR antagonists. The concentration-dependent relaxations then induced by a range of β-AR agonists indicated a potency ranking of isoproterenol > noradrenaline > adrenaline > procaterol. We then investigated the effects of β-AR antagonists that attenuate the effect of isoproterenol (propranolol for β1,2,3-ARs, atenolol for β1-ARs, butoxamine for β2-ARs, and SR 59230A for β3-ARs), with Schild regression analysis, ascertaining multiple β-AR subtypes, with neither the β1-AR nor the β2-AR as the dominant subtype. SR 59230A was the only antagonist to yield a pA2 value (7.52) close to the reported equivalent for the relevant receptor subtype. Furthermore, treatment with SR 58611 (a β3-AR agonist) induced relaxation, which was inhibited (P < 0.01) by L-NNA and SR 59230A. Additionally, treating basilar arterial strips (containing endothelium) with SR 58611 induced nitric oxide (NO) production, which was inhibited (P < 0.01) by L-NNA and SR 59230A. Based on this first characterization of AR subtypes in chicken basilar arteries (to our knowledge), we suggest that α- and β-ARs are involved in contraction and relaxation, and that β3-ARs, especially those on the endothelium, may play an important role in vasodilation via NO release.

Key role for Kv11.1 (ether-a-go-go related gene) channels in rat bladder contractility.

In addition, to their established role in cardiac myocytes and neurons, ion channels encoded by ether-a-go-go-related genes (ERG1-3 or kcnh2,3 and 6) (kcnh2) are functionally relevant in phasic smooth muscle. The aim of the study was to determine the expression and functional impact of ERG expression products in rat urinary bladder smooth muscle using quantitative polymerase chain reaction, immunocytochemistry, whole-cell patch-clamp and isometric tension recording. kcnh2 was expressed in rat bladder, whereas kcnh6 and kcnh3 expression were negligible. Immunofluorescence for the kcnh2 expression product Kv11.1 was detected in the membrane of isolated smooth muscle cells. Potassium currents with voltage-dependent characteristics consistent with Kv11.1 channels and sensitive to the specific blocker E4031 (1μM) were recorded from isolated detrusor smooth muscles. Disabling Kv11.1 activity with specific blockers (E4031 and dofetilide, 0.2-20 μM) augmented spontaneous contractions to a greater extent than BKCa channel blockers, enhanced carbachol-driven activity, increased nerve stimulation-mediated contractions, and impaired β-adrenoceptor-mediated inhibitory responses. These data establish for the first time that Kv11.1 channels are key determinants of contractility in rat detrusor smooth muscle.

Targeted temperature management and PbtO2 in traumatic brain injury

IntroductionTargeted Temperature Management (TTM) to normothermia is widely used in traumatic brain injury (TBI). We investigated the effects to of TTM to normothermia patients with TBI (GCS≤12) monitored with multimodality monitoring, to better understand the physiological consequences of this intervention. Research questionIn TBI patients cooled to normothermia and in which brain oxygenation deteriorates, are there changes in physiological parameters which are pertinent to brain oxygenation? Material and method102 TBI patients with continuous recordings of intracranial pressure (ICP) and brain oxygen tension (PbtO2) were studied retrospectively. Non-continuous arterial carbon dioxide (PaCO2) and oxygen (PaO2) tensions, and core body temperature (Tc) were added. PaO2 and PaCO2 were also corrected for Tc. Transitions from elevated Tc to normothermia were identified in 39 patients. The 8 h pre and post the transition to normothermia were compared. Data is given as median [IQR] or mean (SD). ResultsOverall, normothermia reduced ICP (12 [9–18] −11 [8–17] mmHg, p < 0.009) and Tcore (38.3 [0.3]-36.9 [0.4] oC, p < 0.001), but not PbtO2 (23.3 [16.6]-24.4 [17.2–28.7] mmHg, NS). Normothermia was associated with a fall in PbtO2 in 18 patients (24.5 [9.3] −20.8 [7.6] mmHg). Only in those with a fall in PbtO2 with cooling did ICP (15 [10.8–18.5] −12 [7.8–17.3] mmHg, p = 0.002), and temperature corrected PaCO2 (5.3 [0.5]- 4.9 [0.8] kPa, p = 0.001) decrease. Discussion and conclusionA reduction in PbtO2 was only present in the subgroup of patients with a fall in temperature corrected PaCO2 with cooling. This suggests that even modest temperature changes could result in occult hyperventilation in some patients. pH stat correction of ventilation may be an important factor to consider in future TTM protocols.

Effects of Ethanol on Contraction Strength of Chick Neck Striatum Muscle Following Electrical Stimulation of the Nerve

Introduction: Ethanol is a suitable solvent for many in vivo and ex vivo studies. However, it can interfere with normal muscle contraction and make variations in the results. Contrary to the present study, previous investigations revealed the suppressant effect of ethanol on muscle contraction. Methods: This study was based on an isolated chick biventer cervicis nerve-muscle using the twitch tension recording technique. Nerve and muscle complexes were exposed to several concentrations of ethanol (100, 200, 300, 400, and 500 mM), and impulses were recorded. Results: Twitch height increased in time and dose-dependent manner, and the concentration of 500 mM of ethanol after 30 minutes revealed the most elevation of muscle impulses. Conclusion: The potential effects of ethanol on striated muscle contraction are important and should be considered in studies using ethanol as a solvent.

ELDERLY MOUSE DETRUSOR MAINTAINS ITS PEAK FORCE OF CONTRACTION OVER TIME

Abstract Aging is a risk factor for urinary dysfunction. Detrusor weakening has been thought to contribute to the old bladder phenotype. Animal detrusor strips have been used to study bladder function. Strength of contraction in detrusor strips depends on length. This is referred to as the “length-tension relationship.” The aim of our study was to investigate this relationship in a mouse model by comparing the length-tension relationship in old and mature mice. We hypothesize that aging is associated with no change in active detrusor tension capability, however maximal tension will occur at longer lengths.We used two groups of male C57/Bl6 mice for this study, mature 11-12 month old mice and old 22-23 month old mice. Longitudinal intact bladder strips were harvested and placed in a vertical tissue bath between tension recording transducer hooks. Passive tensions and KCl induced contraction tensions for step-wise increments of stretch were observed.In the old group, normalized strip length at the point of maximum active tension was increased by ~13% on average as compared to the mature group with a statistically significant difference (P value 0.0171). Interestingly, the maximum active tension between groups did not differ by age. In conclusion, detrusor from old mice achieve similar maximum active tensions as that from mature mice, however at an increased length. This finding argues against a common belief that the bladder weakens with age. Instead, the aging bladder may adapt to increased filling volumes with an ability to operate at a similar strength of a younger bladder.

Regional Differences in Intestinal Contractile Responses to Radial Stretch in the Human Lower Gastrointestinal Tract.

Radial stretch evokes an increase or decrease in contractions in the lower gastrointestinal tract via mechanosensory enteric neurons that project into the muscle layers. We aim to elucidate the differences in stretch reflexes according to their location in the human colon. We used healthy intestinal smooth muscle tissue excised during elective colon cancer surgery. Conventional intracellular recordings from colonic muscle cells and tension recordings of colonic segments were performed. Radial stretch was evoked through balloon catheter inflation. Changes in the membrane potential and frequency, amplitude, and area under the curve of muscle contractions were recorded before and after the radial stretch at proximal and distal segment sites. In intracellular circular muscle recordings, hyperpolarization was noted at the distal site of sigmoid colonic segments after radial stretch, in contrast to depolarization at all other sites. In tension recordings at proximal ascending or sigmoid colonic segment sites, contractile activation was observed with statistically significant increases in the frequency, amplitude, and area under the curve after radial stretch. Distal sites of ascending and sigmoid colonic segments showed increase and decrease in contraction, respectively. Radial stretch in the human colon (in vitro) evokes excitatory activity at both proximal and distal sites of the ascending colon and at the proximal site of the sigmoid colon, whereas it elicits inhibitory activity at the distal site of the sigmoid colon.

Regional Differences in Intestinal Contractile Responses to Radial Stretch in the Human Lower Gastrointestinal Tract.

Radial stretch evokes an increase or decrease in contractions in the lower gastrointestinal tract via mechanosensory enteric neurons that project into the muscle layers. We aim to elucidate the differences in stretch reflexes according to their location in the human colon. We used healthy intestinal smooth muscle tissue excised during elective colon cancer surgery. Conventional intracellular recordings from colonic muscle cells and tension recordings of colonic segments were performed. Radial stretch was evoked through balloon catheter inflation. Changes in the membrane potential and frequency, amplitude, and area under the curve of muscle contractions were recorded before and after the radial stretch at proximal and distal segment sites. In intracellular circular muscle recordings, hyperpolarization was noted at the distal site of sigmoid colonic segments after radial stretch, in contrast to depolarization at all other sites. In tension recordings at proximal ascending or sigmoid colonic segment sites, contractile activation was observed with statistically significant increases in the frequency, amplitude, and area under the curve after radial stretch. Distal sites of ascending and sigmoid colonic segments showed increase and decrease in contraction, respectively. Radial stretch in the human colon (in vitro) evokes excitatory activity at both proximal and distal sites of the ascending colon and at the proximal site of the sigmoid colon, whereas it elicits inhibitory activity at the distal site of the sigmoid colon.

Selective reduction of neurotransmitter release by cAMP-dependent pathways in mouse detrusor.

Parasympathetic nerve-mediated contractions of detrusor smooth muscle are generated by ATP and acetylcholine (ACh) release from efferent nerve terminals. In humans, ACh is responsible for detrusor contractions in normal human bladders, whereas ATP has an additional role in overactive bladder pathologies. The ATP metabolite, adenosine, relaxes nerve-mediated contractions, with a potential action via presynaptic adenosine A1 receptor activation and subsequent suppression of neuronal ATP release. We investigated the effect of A1 receptor activation and downstream cAMP-dependent pathways on nerve-mediated ATP and ACh release, and detrusor contraction in mouse detrusor. Bladders from male C57BL/6 mice (12 wk) were used for in vitro experiments. Upon electrical field stimulation of intact preparations (detrusor and mucosal layers), ATP or ACh release was measured simultaneously with tension recordings. Activation of A1 receptors by adenosine or exogenous agonists reduced the lower frequency component of nerve-mediated contractions and neuronal ATP release. The A1 receptor antagonist abolished these effects. A1 receptor activation inhibits adenylyl cyclase (AC) activity and cAMP generation. The effect of A1 receptor activation was mimicked by a PKA antagonist but not by modulators of exchange proteins activated by cAMP, demonstrating that modulation of nerve-mediated ATP release is via PKA. Adenosine had no effect on ACh release or the higher frequency component of nerve-mediated contractions. Differential regulation of neurotransmitter release is possible at the detrusor nerve-muscle junction, as demonstrated by A1 receptor activation, and downstream inhibition of AC, cAMP generation, and PKA. The ability to specifically attenuate ATP release offers a potential to target purinergic motor pathways enhanced in overactive bladder pathologies.

Ligamentum arteriosum: Muscular and contractile.

Ductus arteriosus is a muscular artery in fetal circulation, spanning from the bifurcation of the pulmonary trunk to the aortic arch, shunting blood directly from pulmonary circulation into systemic circulation thus by-passing the fluid-filled lungs. Postnatally, it changes name to the ligamentum arteriosum (LA), when a cascade of anatomical and physiological processes leads to its closure. Though the LA has generally been considered as a fibrosed remnant of the ductus arteriosus, anecdotal and contradictory reports still describe the LA as a small muscular artery. We hypothesized the likelihood of contractile muscular elements retainment in this so-called ligament. To investigate this, mediastinum of wild-type mouse, pig, and human LA were subjected to routine and special histological staining, single-immunolabeling, electron microscopy (mouse and pig only), and tension recording of explanted pig LA in organ bath experiments. Contrary to a canonical ligament, the LA was mainly made up of α-smooth muscle actin-positive cells in all three species, confirmed by routine and special histological staining as well as transmission electron microscopy. Myocytes within the LA contracted in response to exogenous noradrenalin (NA). NA-induced precontracted LA relaxed upon administration of the α1-adrenergic blockers (prazosin and tamsulosin). Though the LA does not function in its original capacity as fetal shunt, it is clearly not a passive structure, and may be described as muscular and contractile. The contractile abilities of LA myocytes may act on the two great vessels to which it is attached causing a change in their distensibility.

Purification and Characterization of a Novel Factor of Crotoxin Inter-CRO (V-1), a New Phospholipase A2 Isoform from Crotalus durissus collilineatus Snake Venom Using an In Vitro Neuromuscular Preparation

The fractionation of Crotalus durissus collilineatus whole venom through an HPLC chromatographic method enabled the purification of a new V-1 neurotoxin. Inter-CRO (V-1) presents similarity in its primary structure to crotoxin B (CB), suggesting another isoform of this toxin. The aim of this study was to compare V-1 to the crotoxin complex (CA/CB) and CB to elucidate aspects related to its functionality. The homogeneity of the purified protein was confirmed with a molecular mass of 1425.45 Da, further verified by mass spectrometry. The sequence of the protein showed high similarity to other viperid snake venom PLA2 proteins. The results of this study report that V-1 is an uncharacterized novel toxin with different biological activities from CB. V-1 maintained catalytic activity but presented neurotoxic activity as observed by the 2.5-fold increase in twitch tension record compared to control values on isolated muscle cells.

Experimental Investigation of Sensorless Tension Control System for Textile Processes

Sensorless tension control system is investigated for textile processes and machines in this paper. A prototype unit unit was designed and manufactured for this aim. Prototype unit consisted of winding and unwinding warp beams driven by a servomotor and an induction motor. Warp tension was measured by load cells for evaluating the sensorless tension control system performance. Diameters of winding and unwinding warp beams were measured by laser sensors. Wound warp length was measured by an incremental encoder fitted to the shaft of a cylinder rotated by warp yarns. Number of beam rotations of warp beams were measured by separate inductive switches. A software program was developed in LabVIEW to implemet sensorless tension control algorithms and record the performance data. Results showed that the desired tension can be kept constant within 5% deviation limits by the servomotor torque control.

Effects of vasopressin receptor agonists on detrusor smooth muscle tone in young and aged bladders: Implications for nocturia treatment

Purpose:The main goal of this study was to determine the effects of arginine vasopressin (AVP) and desmopressin on bladder contractility and to examine whether the effects of these vasopressin receptor (VR) agonists differ in young versus aged animals. These aims were addressed using urinary bladders from young (3 months) and aged (24 month) female Fischer 344 rats that were isolated and dissected into strips for isometric tension recordings. Bladder strips were exposed to AVP and desmopressin through the perfusate, and tension changes recorded. Results:In young rat bladders, AVP, an agonist at both vasopressin-1 receptors (V1Rs) and vasopressin-2 receptor (V2Rs), concentration-dependently caused contraction of bladder strips with a sensitivity that was greater in young versus aged bladder strips. Removal of the mucosa did not alter the sensitivity of young bladder strips to AVP yet enhanced the AVP sensitivity of aged bladder strips. The differential sensitivity to AVP between young denuded and aged denuded bladder strips was similar. In contrast to AVP, desmopressin (V2R selective agonist) relaxed bladder strips. This response was reduced by removal of the mucosa in young, but not aged, bladder strips. Conclusion:These findings support a direct role for VRs in regulating detrusor tone with V1Rs causing contraction and V2Rs relaxation. In aged bladders, the contractile response to V1R activation is attenuated due to release of a mucosal factor that attenuates V1R-induced contractions. Also in aged bladders, the relaxation response to V2R activation is attenuated by lack of release of a mucosal factor that contributes to V2R-induced relaxation. Thus age-associated changes in the bladder mucosa impair the effects of VRs on bladder tone. Because the V2R signaling system is impaired in the older bladder, administering an exogenous V2R agonist (e.g., desmopressin) could counteract this defect. Thus, desmopressin could potentially increase nighttime bladder capacity through detrusor relaxation in concert with decreased urine production, reducing nocturnal voiding frequency.

Inhibition of TRPC4 channel activity in colonic myocytes by tricyclic antidepressants disrupts colonic motility causing constipation

Tricyclic antidepressants (TCAs) have been used to treat depression and were recently approved for treating irritable bowel syndrome (IBS) patients with severe or refractory IBS symptoms. However, the molecular mechanism of TCA action in the gastrointestinal (GI) tract remains poorly understood. Transient receptor potential channel canonical type 4 (TRPC4), which is a Ca2+‐permeable nonselective cation channel, is a critical regulator of GI excitability. Herein, we investigated whether TCA modulates TRPC4 channel activity and which mechanism in colonic myocytes consequently causes constipation. To prove the clinical benefit in patients with diarrhoea caused by TCA treatment, we performed mechanical tension recording of repetitive motor pattern (RMP) in segment, electric field stimulation (EFS)‐induced and spontaneous contractions in isolated muscle strips. From these recordings, we observed that all TCA compounds significantly inhibited contractions of colonic motility in human. To determine the contribution of TRPC4 to colonic motility, we measured the electrical activity of heterologous or endogenous TRPC4 by TCAs using the patch clamp technique in HEK293 cells and murine colonic myocytes. In TRPC4‐overexpressed HEK cells, we observed TCA‐evoked direct inhibition of TRPC4. Compared with TRPC4‐knockout mice, we identified that muscarinic cationic current (mI cat) was suppressed through TRPC4 inhibition by TCA in isolated murine colonic myocytes. Collectively, we suggest that TCA action is responsible for the inhibition of TRPC4 channels in colonic myocytes, ultimately causing constipation. These findings provide clinical insights into abnormal intestinal motility and medical interventions aimed at IBS therapy.

Abstract 154: Endothelial Dysfunction In Experimental Celiac Disease Is Mediated By Gut-Derived Vascular Inflammation And Oxidative Stress

Objective: Celiac disease (CeD) is an autoimmune enteropathy triggered by dietary gluten, with a prevalence around 1%. Since many patients show heterogeneous symptoms, it is vastly underdiagnosed and yet without any treatment option besides lifelong gluten restriction. Vascular function in CeD patients compared to healthy controls has been assessed and hypothesized CeD as a cardiovascular risk factor. Herewith we aimed to explore the cardiovascular effects of CeD in a murine model, with special emphasis on endothelial dysfunction, vascular inflammation, and oxidative stress, known triggers for cardiovascular disease. Methods: NOD.DQ8 mice were raised on a zein-based, gluten-free diet. During the experiment, mice received gavage with peptic-tryptic digest of gliadin and were switched to a gluten-containing diet (Gliadin group). A control group (Zein group) was continued on gluten-free diet and received accordingly digested zein. Results: Blood pressure measurements revealed arterial hypertension in the Gliadin group. Endothelium-dependent relaxation was impaired in the Gliadin group compared to Zein, whereas no change in endothelium-independent was observed, tested by isometric tension recordings. Pro-inflammatory genes, like Tnfa and Nox2 were upregulated in the Gliadin group measured by quantitative rtPCR in aortic and intestinal tissue. Infiltration by intraepithelial T-lymphocytes into the epithelium of the small intestine was shown by IHC. In cardiac tissue, gliadin-treatment increased the oxidative stress parameters 3-nitrotyrosine and 4-hydroxy-2-nonenal shown in dot blots. To investigate the inflammatory link between gut and the cardiovascular system plasma proteomics were performed and revealed elevated levels of IL-17A. Conclusion: CeD is a cardiovascular risk factor. However, the mechanism remains unresolved. In a mouse model, we demonstrate that gluten treatment elevates blood pressure and impairs vascular function. Intestinal inflammation conveys to the cardiovascular system, leads to oxidative stress, and thereby impairs endothelial function. A potential mediator might be IL-17A, whose role in other autoimmunity-based cardiovascular risk factors (e.g., psoriasis) has already been demonstrated.

SKA-31-induced activation of small-conductance calcium-activated potassium channels decreased modulation of detrusor smooth muscle function in a rat model of obesity

Increased excitability and contractility of detrusor smooth muscle (DSM) cells are associated with overactive bladder (OAB), which is often induced by obesity. Small-conductance Ca2+-activated K+ (SK) channels regulate the excitability and contractility of DSM cells. Selective pharmacological activation of SK channels attenuates hyperpolarization and the decreased relaxation effect in DSM cells in obesity-induced OAB. However, additional data are needed to confirm the regulatory effect of SK channels on the function of DSM cells in obesity-related OAB. The tested hypothesis was that activation of SK channels decreases modulation of DSM function in a rat model of obesity-related OAB. Female Sprague Dawley rats were fed a normal diet (ND) or a high-fat diet (HFD), weighed after 12weeks, and subjected to urodynamic study, patch-clamp electrophysiology, and isometric tension recording. The average body weight and incidence of OAB were increased in the HFD group. Patch-clamp studies revealed that pharmacological activation of SK channels with SKA-31 had attenuated hyperpolarization of DSM cells. In addition, isometric tension recordings indicated that SKA-31 decreased relaxation of spontaneous phasic contractions of DSM strips in the HFD group. Attenuated function of SK channels increased the excitability and contractility of DSM cells, which contributed to the occurrence of OAB, suggesting that SK channels are potential therapeutic targets for control of OAB.

Endothelium-dependent vasorelaxant effects of praeruptorin a in isolated rat thoracic aorta

ABSTRACT Praeruptorin A (PA) is a natural coumarin compound from the roots of Radix Peucedani and is commonly used in the treatment of certain respiratory diseases and hypertension. Although previous studies identified relaxant effects of PA on tracheal and arterial preparations, little is known about its vasodilative effects and underlying mechanisms. Here, an organ bath system and tension recording methods were used to prepare and analyze isolated rat thoracic aorta artery rings. Aorta artery rings were pre-contracted with phenylephrine and then incubated with PA, and the possible mechanism of relaxation was investigated by adding inhibitors of nitric oxide synthase (NG-nitro-L-arginine methyl ester, L-NAME), endothelial nitric oxide synthase (L-NG-nitroarginine, L-NNA), cyclooxygenase (indomethacin), guanylyl cyclase (1 H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one, ODQ), and KCa channels (tetraethylammonium, TEA). Our study showed that PA-induced vasodilation was blocked by L-NAME, L-NNA, and ODQ, while CaCl2-induced vasoconstriction was countered by PA. Thus, PA may exert a vasodilatory effect by influencing the amounts of endothelium-derived relaxing factors through endothelial-dependent NO-cGMP and prostacyclin pathways (such as NO and prostacyclin 2). In the rat thoracic aorta, PA reduces vasoconstriction by inhibiting Ca2+ inflow.

Deleterious effects of levamisole, a cocaine adulterant, in rabbit aorta

Levamisole, a veterinary anthelmintic drug, is one of the most widely used and dangerous cocaine adulterants. Like cocaine, levamisole acutely blocks noradrenaline reuptake but with much less potency, although its vascular effects are not well known. In this study, we evaluated the vascular effects of levamisole and cocaine in rabbit aortic rings used for isometric recording of tension in organ baths and protein expression by western blot. Our results indicated that levamisole (10−5–10−3 M) induced a concentration-dependent relaxation in rings precontracted with noradrenaline (10−7–3 × 10−7 M). Furthermore, it reduced the contractile response to phenylephrine (10−9–3 × 10−5 M) that was not modified by cocaine (10−5–10−4 M), and reduced α1-adrenergic receptor expression. Levamisole (10−6–10−4 M) produced a potentiation of the electrical field stimulation that was not further enhanced by the combination of both drugs. However, high concentrations of levamisole (10−3 M) abolished adrenergic neurotransmission whether administered alone or with cocaine (10−4 M). In addition, levamisole (10−5–10−3 M) also decreased endothelium-dependent relaxation to acetylcholine that was not further impaired by cocaine (10−4 M), and that was partially reversed by superoxide dismutase (SOD, 200 U/ml). These results demonstrate that levamisole has a dual effect on the adrenergic system, and its effects are independent of the presence of cocaine. At lower concentrations, it enhances the contractile sympathetic response by blocking presynaptic α2-adrenergic receptors, while at high concentrations, the effect of the antagonism of α1-adrenergic receptor prevails. In addition, levamisole induces endothelial dysfunction by reducing NO bioavailability, and this effect could be in part mediated by oxidative stress.