Methotrexate and electrostimulation cooperate to alleviate the relapse of psoriasiform skin inflammation by suppressing memory T cells.

Methotrexate (MTX) is an immunosuppressant used to treat autoimmune diseases, including psoriasis. However, like other immunosuppressants, MTX alone does not prevent their recurrence. Electrostimulation (ES) has been utilized to treat some inflammatory disorders without any major side-effect. But it remains unknown if ES alone, or together with MTX, ameliorates autoimmune disease relapse: a sticky medical problem. In particular, the mechanisms underlying ES action remain unclear. The objective of this study was to determine an impact of ES and/or MTX on psoriasis relapse and their potential cooperation. We found that regional ES, but not MTX, ameliorated psoriasiform skin inflammation recurrence. Interestingly, treatment with both MTX and ES further prevented psoriasis recurrence compared to ES alone. Moreover, ES downregulated potassium channel Kv1.3 on T-cells and reduced CD4+/CD8+ effector memory (TEM) and CD8+ skin-resident memory T (TRM) cells, while ES plus MTX further decreased CD8+ TEM/TRM cells compared to ES alone. However, ES failed to further attenuate psoriasis recurrence or suppress T cell memory in Kv1.3-deficient mice, whereas lack of Kv1.3 itself ameliorated psoriasis relapse by shrinking T cell memory pool. Importantly, ES moderately inhibited T-cell proliferation in vitro. ES also reduced human CD8+ TRM cells and attenuated human skin lesions in humanized mice grafted with lesional skin from patients with recurrent psoriasis, with an enhanced efficacy in mice treated with both ES and MTX. Thus, ES and MTX cooperated to prevent psoriasis relapse by reducing T-cell memory via targeting potassium channel Kv1.3. Our studies may be implicated for treating human psoriasis.

Effects of Chaerophyllum macropodum Boiss. leaves essential oil in inflammatory and neuropathic pain: uncovering the possible mechanism of action.

BACKGROUND: Chaerophyllum macropodum Boiss. (popularly known as "Jafari farangi kohestani") is a predominant medicinal plant traditionally utilized in the treatments of peritoneal inflammation and headache in Persian folk medicine. Here, we have revealed the anti-neuropathic and anti-nociceptive activities of C. macropodum leaves essential oil (CMEO) in addition to uncovering the possible mechanisms of action. METHODS: Formalin-induced paw licking model was used to assess the anti-nociceptive activity of CMEO and its major constituent, terpinolene (TP). The anti-nociceptive activity of these compounds was determined by investigating the roles of various non-opioid and NO-cGMP-K+ channels. Additionally, the anti-neuropathic potential of CMEO and TP was determined using cervical spinal cord contusion/CCS technique. RESULTS: The CMEO exerted significant anti-nociceptive activity with a remarkable activity seen in the second phase of formalin-induced paw licking model and this activity were remarkably reversed by pre-treatment of naloxone (an opioid antagonist). Pretreatment with several types of NO-cGMP-potassium channel pathway meaningfully reversed the anti-nociceptive potential of CMEO in phase II of formalin model. Moreover, pre-treatment with several antagonists of non-opioid receptors revealed that only the antagonist of TRPV-1, serotonin type 3, 5-HT2, α2 adrenergic, and CB1 receptors (capsaicin, ondansetron, ketanserin, yohimbine, and SR141716A, respectively) reversed CMEO anti-nociception. CMEO and TP also remarkably reversed hyperalgesia and mechanical allodynia in the CCS technique. CONCLUSION: The CMEO exerts anti-nociceptive and anti-neuropathic activities via the modulation of NO-cGMP potassium channel pathway, opioid as well as several non-opioid receptor activity. TP might partly contribute to the observed activities of CMEO.

Electroacupuncture inhibits PDK1/Akt/HCN4 pathway to improve neurogenic urinary retention in rats. / 电针通过抑制PDK1/Akt/HCN4é€šè·¯æ”¹å–„å¤§é¼ ç¥žç»æºæ€§å°¿æ½´ç•™.

OBJECTIVES: To observe the therapeutic effect of electroacupuncture (EA) on neurogenic urinary retention rats, so as to explore the underlying mechanism of EA in treating neurogenic urinary retention by focusing on 3-phosphoinositide-dependent protein kinase 1 (PDK1)/protein kinase B (Akt)/hyperpolarization activated cyclic nucleotide-gated cation channel 4 (HCN4) pathway. METHODS: Female SD rats were randomly divided into sham operation, model, EA, PDK1 inhibitor, HCN4 blocker and EA + HCN4 blocker groups, with 20 rats in each group. The model of sacral spinal cord injury was established by modified Hassan Shaker spinal cord transection method. EA (2 Hz/15 Hz, 0.5 mA) was applied to "Zhongji" (CV3) and "Zhongliao" (BL33) for 20 min, once daily for 10 days. Rats of the PDK1 inhibitor group received intraperitoneal injection of OSU-03012 (20 mg/kg), and rats of the HCN4 blocker group received intraperitoneal injection of ivabradine (10 mg/kg), both once every other day for 10 days. The urodynamic indexes of rats were detected by multi-channel physiological recorder；muscle strip test was used to detect detrusor excitability；the morphological changes of bladder were observed by HE staining. Immunofluorescence double staining was used to detect the co-expression of HCN4 and C-Kit, a specific marker of interstitial cells of Cajal in bladder. Western blot was used to detect the expression of PDK1/Akt/HCN4 pathway proteins in bladder tissue and heat shock protein 27 (HSP27), a protein related to bladder contraction function. RESULTS: Compared with the sham operation group, the rats in the model group showed urinary dysfunction, decreased leak point pressure, isolated detrusor spontaneous contraction frequency, fluorescence intensity of C-Kit positive cells, HCN4+/C-Kit+ co-expression, HCN4 and p-HSP27/HSP27 protein expression in bladder tissue (P<0.05), and increased maximum bladder capacity and comp-liance, minimum tension during contraction of isolated detrusor, PDK1 and p-Akt/Akt protein expression in bladder tissue (P<0.05). Meanwhile, the above index were all reversed after EA and PDK1 inhibitor intervention (P<0.05). In comparison with the EA group, the rats had severe urinary dysfunction, the urine leakage point pressure, spontaneous contraction frequency, fluorescence intensity of C-Kit positive cells, the co-expression of HCN4+/C-Kit+, and the protein expression of HCN4 and p-HSP27/HSP27 were decreased (P<0.05), the maximum bladder capacity and compliance, the minimum tension during contraction of isolated detrusor, and the protein expression of PDK1 and p-Akt/Akt in bladder tissue were increased (P<0.05) in both HCN4 blocker and EA+HCN4 blocker groups. HE staining showed exfoliated bladder epithelium and disordered layers, vacuolization of bladder wall cells, with infiltration of neutrophils in mucosal and muscular layers in the model group, which were relatively milder in the EA and PDK1 inhibitor groups, but worse in the HCN4 blocker and EA + HCN4 blocker groups. CONCLUSIONS: EA can improve the urinary dysfunction in rats with neurogenic urinary retention, which may be related to its effect in inhibiting the activation of PDK1/Akt pathway, promo-ting HCN4-mediated detrusor excitatory contraction and urinary electrical signal activation.

NIR-II Regulation of Mitochondrial Potassium Channel with Dual-Targeted Conjugated Oligomer Nanoparticles for Efficient Cancer Theranostics In Vivo.

Cell fate can be efficiently modulated by switching ion channels. However, the precise regulation of ion channels in cells, especially in specific organelles, remains challenging. Herein, biomimetic second near-infrared (NIR-II) responsive conjugated oligomer nanoparticles with dual-targeted properties are designed and prepared to modulate the ion channels of mitochondria to selectively kill malignant cells in vivo. Upon 1060 nm laser irradiation, the mitochondria-located nanoparticles photothermally release a specific ion inhibitor of the potassium channel via a temperature-sensitive liposome, thus altering the redox balance and pathways of mitochondria. NIR-II responsive nanoparticles can effectively regulate the potassium channels of mitochondria and fully suppress tumor growth. This work provides a new modality based on the NIR-II nanoplatform to regulate ion channels in specific organelles and proposes an effective therapeutic mechanism for malignant tumors.

Kalium 3.0 is a comprehensive depository of natural, artificial, and labeled polypeptides acting on potassium channels.

Here, we introduce the third release of Kalium database (http://kaliumdb.org/), a manually curated comprehensive depository that accumulates data on polypeptide ligands of potassium channels. The major goal of this amplitudinous update is to summarize findings for natural polypeptide ligands of K+ channels, as well as data for the artificial derivatives of these substances obtained over the decades of exploration. We manually analyzed more than 700 original manuscripts and systematized the information on mutagenesis, production of radio- and fluorescently labeled derivatives, and the molecular pharmacology of K+ channel ligands. As a result, data on more than 1200 substances were processed and added enriching the database content fivefold. We also included the electrophysiological data obtained on the understudied and neglected K+ channels including the heteromeric and concatenated channels. We associated target channels in Kalium with corresponding entries in the official database of the International Union of Basic and Clinical Pharmacology. Kalium was supplemented with an adaptive Statistics page, where users are able to obtain actual data output. Several other improvements were introduced, such as a color code to distinguish the range of ligand activity concentrations and advanced tools for filtration and sorting. Kalium is a fully open-access database, crosslinked to other databases of interest. It can be utilized as a convenient resource containing ample up-to-date information about polypeptide ligands of K+ channels.

[Antiarrhythmic active components in traditional Chinese medicine acting on potassium channels].

Arrhythmia is an external manifestation of cardiac electrophysiological disorder. It exists in healthy people and patients with various heart diseases, which is often associated with other cardiovascular diseases. The contraction and diastole of myocardium are inseparable from the movement of ions. There are many ion channels in the membrane and organelle membrane of myocardium. The dynamic balance of myocardial ions is vital in maintaining myocardial electrical homeostasis. Potassium ion channels that have a complex variety and a wide distribution are involved in the whole process of resting potential and action potential of cardiomyocytes. Potassium ion channels play a vital role in maintaining normal electrophysiological activity of myocardium and is one of the pathogenesis of arrhythmia. Traditional Chinese medicine(TCM)has unique advantages in treating arrhythmia for its complex active components and diverse targets. A large number of TCM preparations have definite effect on treating arrhythmia-related diseases, whose antiarrhythmic mechanism may be related to the effect on potassium channel. This article mainly reviewed the relevant studies on the active components in TCM acting on different potassium channels to provide references for clinical drug use and development.

Tongmai Yangxin pill alleviates myocardial no-reflow by activating GPER to regulate HIF-1α signaling and downstream potassium channels.

CONTEXT: The Tongmai Yangxin pill (TMYX) has potential clinical effects on no-reflow (NR); however, the effective substances and mechanisms remain unclear. OBJECTIVE: This study evaluates the cardioprotective effects and molecular mechanisms of TMYX against NR. MATERIALS AND METHODS: We used a myocardial NR rat model to confirm the effect and mechanism of action of TMYX in alleviating NR. Sprague-Dawley (SD) rats were divided into Control (Con), sham, NR, TMYX (4.0 g/kg), and sodium nitroprusside (SNP, 5.0 mg/kg), and received their treatments once a day for one week. In vitro studies in isolated coronary microvasculature of NR rats and in silico network pharmacology analyses were performed to reveal the underlying mechanisms of TMYX and determine the main components, targets, and pathways of TMYX, respectively. RESULTS: TMYX (4.0 g/kg) showed therapeutic effects on NR by improving the cardiac structure and function, reducing NR, ischemic areas, and cardiomyocyte injury, and decreasing the expression of cardiac troponin I (cTnI). Moreover, the mechanism of TMYX predicted by network pharmacology is related to the HIF-1, NF-κB, and TNF signaling pathways. In vivo, TMYX decreased the expression of MPO, NF-κB, and TNF-α and increased the expression of GPER, p-ERK, and HIF-1α. In vitro, TMYX enhanced the diastolic function of coronary microvascular cells; however, this effect was inhibited by G-15, H-89, L-NAME, ODQ and four K+ channel inhibitors. CONCLUSIONS: TMYX exerts its pharmacological effects in the treatment of NR via multiple targets. However, the contribution of each pathway was not detected, and the mechanisms should be further investigated.

Identification and characterization of the key lethal toxin from jellyfish Cyanea nozakii.

Jellyfish Cyanea nozakii venom is a complex mixture of various toxins, most of which are proteinous biological macromolecules and are considered to be responsible for clinical symptoms or even death after a severe sting. Previous transcriptome and proteome analysis identified hundreds of toxins in the venom, including hemolysins, C-type lectin, phospholipase A2, potassium channel inhibitor, metalloprotease, etc. However, it is not clear which toxin in the venom plays the most important role in lethality. Herein, we isolated the key lethal toxin (Letoxcn) from jellyfish Cyanea nozakii using anion exchange chromatography, size-exclusion chromatography, and cation exchange chromatography. The molecular weight of Letoxcn is ∼50 kDa with the N-terminal sequences of QADAEKVNLPVGVCV. Peptide mass fingerprinting analysis of Letoxcn shows that it may have some motifs of phospholipase, metalloproteinase, thrombin-like enzyme, potassium channel toxin, etc. However, only metalloproteinase activity but no hemolytic, PLA2, or blood coagulation activity was observed from in vitro toxicity analysis. Overall, this study uncovered and characterized the key lethal toxin in the venom of jellyfish Cyanea nozakii, which will not only help to reveal the molecule mechanism of the lethality, but also develop effective treatment like antivenom for this jellyfish sting in the future.

Antiarrhythmic active components in traditional Chinese medicine acting on potassium channels / 中国中药杂志

Arrhythmia is an external manifestation of cardiac electrophysiological disorder. It exists in healthy people and patients with various heart diseases, which is often associated with other cardiovascular diseases. The contraction and diastole of myocardium are inseparable from the movement of ions. There are many ion channels in the membrane and organelle membrane of myocardium. The dynamic balance of myocardial ions is vital in maintaining myocardial electrical homeostasis. Potassium ion channels that have a complex variety and a wide distribution are involved in the whole process of resting potential and action potential of cardiomyocytes. Potassium ion channels play a vital role in maintaining normal electrophysiological activity of myocardium and is one of the pathogenesis of arrhythmia. Traditional Chinese medicine(TCM)has unique advantages in treating arrhythmia for its complex active components and diverse targets. A large number of TCM preparations have definite effect on treating arrhythmia-related diseases, whose antiarrhythmic mechanism may be related to the effect on potassium channel. This article mainly reviewed the relevant studies on the active components in TCM acting on different potassium channels to provide references for clinical drug use and development.

[Association study between the KCNE family gene polymorphisms of potassium channel gene and the susceptibility of atrial fibrillation].

Objective: To investigate the relationship between KCNE family gene polymorphisms of potassium channel gene and the susceptibility of atrial fibrillation (AF). Methods: In the case-control study, a total of 648 subjects were studied, of which 338 patients with atrial fibrillation were selected from the Department of Cardiovascular Medicine, Putuo Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from January 2019 to December 2019, and 310 healthy people were selected from the physical examination population during the same period. DNA sequencing technology and polymerase chain reaction (PCR) were used to detect the genotype and allele frequency of rs1805127 of KCNE1, rs9984281 of KCNE2, rs9516, rs626930 of KCNE3 and rs12621643 of KCNE4. Results: The ages of subjects in atrial fibrillation group and control group were (69±13) and (73±8) years, respectively (P=0.077). Men subjects accounted for 57.70% (195 men) and 40.00% (124 men) in the two groups, respectively (P=0.092). The distribution frequencies of the allele C at rs1805127 of gene KCNE1, the allele A at rs9984281 of gene KCNE2 and the allele G at rs12621643 of gene KCNE4 were significantly different between groups (P<0.05). After adjustment for sex, smoking, hypertension, cardiac insufficiency and other factors, it was found that the increase in the frequency of the above three loci would increase the risk of atrial fibrillation (rs1805127 OR=7.064, 95%CI:1.559-31.997; rs9984281 OR=4.210, 95%CI:1.118-15.850; rs12621643 OR=2.679, 95%CI:1.025-6.998). Conclusion: The rs1805127 of KCNE1, the rs9984281 of KCNE2,the rs12621643 of KCNE4 were significantly associated with the susceptibility to atrial fibrillation.

Emerging mechanisms involving brain Kv7 channel in the pathogenesis of hypertension.

Hypertension is a prevalent health problem inducing many organ damages. The pathogenesis of hypertension involves a complex integration of different organ systems including the brain. The elevated sympathetic nerve activity is closely related to the etiology of hypertension. Ion channels are critical regulators of neuronal excitability. Several mechanisms have been proposed to contribute to hypothalamic-driven elevated sympathetic activity, including altered ion channel function. Recent findings indicate one of the voltage-gated potassium channels, Kv7 channels (M channels), plays a vital role in regulating cardiovascular-related neurons activity, and the expression of Kv7 channels is downregulated in hypertension. This review highlights recent findings that the Kv7 channels in the brain, blood vessels, and kidneys are emerging targets involved in the pathogenesis of hypertension, suggesting new therapeutic targets for treating drug-resistant, neurogenic hypertension.

Transcriptome Sequencing and Comparison of Venom Glands Revealed Intraspecific Differentiation and Expression Characteristics of Toxin and Defensin Genes in Mesobuthus martensii Populations.

Mesobuthus martensii, a famous and important Traditional Chinese Medicine has a long medical history and unique functions. It is the first scorpion species whose whole genome was sequenced worldwide. In addition, it is the most widespread and infamous poisonous animal in northern China with complex habitats. It possesses several kinds of toxins that can regulate different ion channels and serve as crucial natural drug resources. Extensive and in-depth studies have been performed on the structures and functions of toxins of M. martensii. In this research, we compared the morphology of M. martensii populations from different localities and calculated the COI genetic distance to determine intraspecific variations. Transcriptome sequencing by RNA-sequencing of the venom glands of M. martensii from ten localities and M. eupeus from one locality was analyzed. The results revealed intraspecific variation in the expression of sodium channel toxin genes, potassium channel toxin genes, calcium channel toxin genes, chloride channel toxin genes, and defensin genes that could be related to the habitats in which these populations are distributed, except the genetic relationships. However, it is not the same in different toxin families. M. martensii and M. eupeus exhibit sexual dimorphism under the expression of toxin genes, which also vary in different toxin families. The following order was recorded in the difference of expression of sodium channel toxin genes: interspecific difference; differences among different populations of the same species; differences between sexes in the same population, whereas the order in the difference of expression of potassium channel toxin genes was interspecific difference; differences between both sexes of same populations; differences among the same sex in different populations of the same species. In addition, there existed fewer expressed genes of calcium channel toxins, chloride channel toxins, and defensins (no more than four members in each family), and their expression differences were not distinct. Interestingly, the expression of two calcium channel toxin genes showed a preference for males and certain populations. We found a difference in the expression of sodium channel toxin genes, potassium channel toxin genes, and chloride channel toxin genes between M. martensii and M. eupeus. In most cases, the expression of one member of the toxin gene clusters distributed in series on the genome were close in different populations and genders, and the members of most clusters expressed in same population and gender tended to be the different. Twenty-one toxin genes were found with the MS/MS identification evidence of M. martensii venom. Since scorpions were not subjected to electrical stimulation or other special treatments before conducting the transcriptome extraction experiment, the results suggested the presence of intraspecific variation and sexual dimorphism of toxin components which revealed the expression characteristics of toxin and defensin genes in M. martensii. We believe this study will promote further in-depth research and use of scorpions and their toxin resources, which in turn will be helpful in standardizing the identification and medical applications of Quanxie in traditional Chinese medicine.

New insights on the phytochemical intervention for the treatment of neuropsychiatric disorders using the leaves of Michelia champaca: an in vivo and in silico approach.

CONTEXT: Michelia champaca L. (Magnoliaceae) has been known since ancient times for its rich medicinal properties. OBJECTIVE: The ethanol extract of Michelia champaca leaves (EEMC) was evaluated on depression and anxiety using in vivo and in silico studies. MATERIALS AND METHODS: Swiss albino mice were divided into control, standard, 100 and 200 mg/kg b.w. EEMC groups and for drug administration using oral gavage. The antidepressant activity was evaluated using forced swim test (FST) and tail suspension test (TST) whereas the anxiolytic activity through elevated plus maze and light and dark tests. The in silico studies included molecular docking against human potassium channel KCSA-FAB and human serotonin transporter, and ADME/T analysis. RESULTS: Open arm duration and entries were comparable between 200 mg/kg b.w. group (184.45 ± 1.00 s and 6.25 ± 1.11, respectively) and that of diazepam treated group (180.02 s ± 0.40 and 6.10 ± 0.05, respectively). Time spent in the light cubicle was higher (46.86 ± 0.03%), similar to that of diazepam (44.33 ± 0.64%), suggesting its potent anxiolytic activity. A delayed onset of immobility and lowered immobility time was seen at both the treatment doses (FST: 93.7 ± 1.70 and 89.1 ± 0.40 s; TST: 35.05 ± 2.75 and 38.50 ± 4.10 s) and the standard drug imipramine (FST: 72.7 ± 3.72 and TST: 30.01 ± 2.99 s), indicative of its antidepressant ability. In silico studies predicted doripenem to induce anxiolytic and antidepressant activity by inhibiting human potassium channel KCSA-FAB and human serotonin transporter proteins, respectively. CONCLUSIONS: EEMC is a rich source of bioactive compounds with strong antidepressant and anxiolytic properties.

Structure-Based Optimization of Coumestan Derivatives as Polyketide Synthase 13-Thioesterase(Pks13-TE) Inhibitors with Improved hERG Profiles for Mycobacterium tuberculosis Treatment.

Pks13 was identified as a key enzyme involved in the final step of mycolic acid biosynthesis. We previously identified antitubercular coumestans that targeted Pks13-TE, and these compounds exhibited high potency both in vitro and in vivo. However, lead compound 8 presented potential safety concerns because it inhibits the hERG potassium channel in electrophysiology patch-clamp assays (IC50 = 0.52 µM). By comparing the Pks13-TE-compound 8 complex and the ligand-binding pocket of the hERG ion channel, fluoro-substituted and oxazine-containing coumestans were designed and synthesized. Fluoro-substituted compound 23 and oxazine-containing coumestan 32 showed excellent antitubercular activity against both drug-susceptible and drug-resistant Mtb strains (MIC = 0.0039-0.0078 µg/mL) and exhibited limited hERG inhibition (IC50 ≥ 25 µM). Moreover, 32 exhibited improved metabolic stability relative to parent compound 8 while showing favorable bioavailability in mouse models via serum inhibition titration assays.

Effects of taurine on vascular tone.

Taurine is widely distributed at high concentrations in mammalian tissues, and it plays an important role in a wide range of biological effects including modulation of cardiovascular functions. This review summarizes the role of taurine in vascular tone and blood pressure modulation based on experimental and human studies. It is well established that supplementation of taurine prevents development of hypertension in several animal models and p.o. taurine administration reduces blood pressure in hypertensive patients. Both central and peripheral actions of taurine may be involved in its hypotensive effects. In isolated animal arteries, taurine exerts vasodilation through endothelium-dependent and independent mechanisms. Several studies showed that taurine relaxed various animal arteries through opening potassium channels. We have recently shown that taurine relaxes human internal mammary and radial arteries by opening large conductance Ca2+-activated K+ channels. To date, the molecular mechanism(s) involved in the vascular effects of taurine are largely unknown and require further investigation. Clarifying the mechanisms in which taurine affects the vascular system may facilitate the development of therapeutic and/or diet-based strategies to reduce the burden of vascular diseases.

The NO-cGMP-K+ Channel Pathway Participates in Diuretic and Cardioprotective Effects of Blutaparon portulacoides in Spontaneously Hypertensive Rats.

Blutaparon portulacoides is a Brazilian plant species that is widely used in folk medicine. The present study investigated the role of an aqueous extract of B. portulacoides against hypertension in spontaneously hypertensive rats. The aqueous extract of B. portulacoides was obtained from the whole plant. Its chemical profile was analyzed by ultraperformance liquid chromatography-tandem mass spectrometry. The acute toxicity of the aqueous extract of B. portulacoides was evaluated in female Wistar rats. Male 6-month-old spontaneously hypertensive rats then received the aqueous extract of B. portulacoides (30, 100, and 300 mg/kg), hydrochlorothiazide (25 mg/kg), or vehicle once daily for 28 days. On days 1, 14, and 28, the diuretic effects of the aqueous extract of B. portulacoides were evaluated. The role of prostaglandins and the nitric oxide-cyclic guanosine monophosphate-potassium channel pathway in the diuretic activity of the aqueous extract of B. portulacoides was also investigated. At the end of the treatment, hepatic and renal biochemical markers, serum nitrotyrosine, malondialdehyde, nitrite, and aldosterone levels, and angiotensin-converting enzyme activity were measured. The electrocardiographic profile, blood pressure, and renal vascular reactivity were also assessed. The heart, kidneys, and liver were collected to determine relative organ weight, histopathology, and cardiac morphometry. Caffeic acid, ferulic acid, and several flavonoids were identified in the aqueous extract of B. portulacoides. No signs of toxicity were observed. Prolonged treatment with the aqueous extract of B. portulacoides (300 mg/kg) induced significant diuretic activity by activating the nitric oxide-cyclic guanosine monophosphate-potassium channel pathway. These effects reduced blood pressure and oxidative stress and prevented renal vascular dysfunction and left ventricular hypertrophy that was induced by hypertension. Overall, the present data suggest that the aqueous extract of B. portulacoides has important diuretic and cardioprotective effects by activation of the nitric oxide-cyclic guanosine monophosphate-potassium channel pathway.

Protective effects of 5(S)-5-carboxystrictosidine on myocardial ischemia-reperfusion injury through activation of mitochondrial KATP channels.

5(S)-5-carboxystrictosidine (5-CS) is a compound found in Mappianthus iodoides Hand.-Mazz., root, a traditional Chinese medicine used for the treatment of coronary artery disease. In this study, we investigated whether 5-CS protects heart against I/R injury. Sprague-Dawley rats were treated with 5-CS intraperitoneally for 7 days before the experiment. Hearts were perfused for 20 min global ischemia and 180 min reperfusion. 5-CS significantly inhibited an increase in the post-ischemic left ventricular end-diastolic pressure (LVEDP) and improved the post-ischemic left ventricular developed pressure (LVDP), dP/dt maximum and dP/dt minimum rates of pressure change, and coronary flow as compared with sham group. Pretreatment with 5-hydroxydecanoic acid (5-HD), an inhibitor of mitochondrial KATP channel, for 10 min before ischemia attenuated the improvement of LVEDP, LVDP, dP/dt maximum and dP/dt minimum rates of pressure change, and coronary flow induced by 5-CS. 5-CS markedly decreased the infarct size and attenuated the increased lactate dehydrogenase (LDH) level in effluent during reperfusion. Pretreatment with 5-HD also blocked these protective effects of 5-CS. 5-CS increased Mn-SOD, catalase, and HO-1 levels decreased by I/R injury and pretreatment of 5-HD blocked the 5-CS effects. Increases in Bax, cleaved caspase-3 and cytochrome c levels, caspase-3 and caspase-9 activity, and decrease in Bcl-2 level by I/R injury were attenuated by 5-CS treatment and pretreatment of 5-HD blocked its effects. These results suggest that the protective effects of 5-CS against myocardial I/R injury may be partly related to activating antioxidant enzymes and suppressing apoptosis through opening mitochondrial KATP channels.

Lippia origanoides essential oil induces tocolytic effect in virgin rat uterus and inhibits writhing in a dysmenorrhea mouse model.

ETHNOPHARMACOLOGICAL RELEVANCE: The species Lippia origanoides Kunth, popularly known as "salva-de-marajó", is used in Brazilian traditional "quilombola" communities to treat menstrual cramps and uterine inflammation. AIM OF THE STUDY: Evaluate the spasmolytic activity of Lippia origanoides essential oil (LOO) on experimental models of uterine conditions related to menstrual cramps and investigate its mechanism of action. MATERIALS AND METHODS: Virgin rat-isolated uterus was mounted in the organ bath apparatus to evaluate the spasmolytic effect of LOO on basal tonus and contractions induced by carbachol, KCl, or oxytocin. We used pharmacological agents to verify the relaxation mechanism of LOO. The evaluation of uterine contractility in virgin rats, after treatment with LOO for three consecutive days, was carried out by the construction of a concentration-response curve with oxytocin or carbachol. The primary dysmenorrhea animal model was replicated with an injection of estradiol cypionate in female mice for three consecutive days, followed by intraperitoneal application of oxytocin. RESULTS: LOO relaxed the rat uterus precontracted with 10-2 IU/mL oxytocin (logEC50 = 1.98 ± 0.07), 1 µM carbachol (logEC50 = 1.42 ± 0.07) or 60 mM KCl (logEC50 = 1.53 ± 0.05). It was also able relax uterus on spontaneous contractions (logEC50 = 0.41 ± 0.05). Preincubation with glibenclamide, propranolol, phentolamine or L-NAME in contractions induced by carbachol did not alter significantly the relaxing effect of LOO. However, in the presence of 4-aminopyridine, CsCl or tetraethylammonium there was a reduction of LOO potency, whereas the blockers methylene blue, ODQ, aminophylline and heparin potentiated the LOO relaxing effect. Preincubation with LOO in a Ca2+ free medium at concentrations of 27 µg/mL or 81 µg/mL reduced the contraction induced by carbachol. The administration of LOO for 3 days did not alter uterus contractility. The treatment with LOO at 30 or 100 mg/kg intraperitoneally, or 100 mg/kg orally, inhibited writhing in female mice. The association of LOO at 10 mg/kg with nifedipine or mefenamic acid potentiated writhing inhibition in mice. CONCLUSIONS: The essential oil of L. origanoides has tocolytic activity in rat isolated uterus pre-contracted with KCl, oxytocin, or carbachol. This effect is possibly related to the opening of potassium channels (Kir, KV, and KCa), cAMP increase, and diminution of intracellular Ca2+. This relaxant effect, probably, contributed to reduce the number of writhings in an animal model of dysmenorrhea being potentiated by nifedipine or mefenamic acid. Taken together, the results here presented indicate that this species has a pharmacological potential for the treatment of primary dysmenorrhea, supporting its use in folk medicine.

The 40-Hz White Light-Emitting Diode (LED) Improves the Structure-Function of the Brain Mitochondrial KATP Channel and Respiratory Chain Activities in Amyloid Beta Toxicity.

It has been described that using noninvasive exposure to 40-Hz white light LED reduces amyloid-beta, a peptide thought to initiate neurotoxic events in Alzheimer's disease (AD). However, the mechanisms remain to be identified. Since AD impairs mitochondrial potassium channels and respiratory chain activity, the objectives of the current study were to determine the effect of 40-Hz white light LED on structure-function of mitoKATP channel and brain mitochondrial respiratory chain activity, production of reactive oxygen species (ROS), and ΔΨm in AD. Single mitoKATP channel was considered using a channel incorporated into the bilayer lipid membrane and expression of mitoKATP-Kir6.1 subunit as a pore-forming subunit of the channel was determined using a western blot analysis in Aß1-42 toxicity and light-treated rats. Our results indicated a severe decrease in mito-KATP channel permeation and Kir6.1 subunit expression coming from the Aß1-42-induced neurotoxicity. Furthermore, we found that Aß1-42-induced neurotoxicity decreased activities of complexes I and IV and increased ROS production and ΔΨm. Surprisingly, light therapy increased channel permeation and mitoKATP-Kir6.1 subunit expression. Noninvasive 40-Hz white light LED treatment also increased activities of complexes I and IV and decreased ROS production and ΔΨm up to ~ 70%. Here, we report that brain mito-KATP channel and respiratory chain are, at least in part, novel targets of 40-Hz white light LED therapy in AD.

Risk of out-of-hospital cardiac arrest in antidepressant drug users.

Conflicting results have been reported regarding the association between antidepressant use and out-of-hospital cardiac arrest (OHCA) risk. We investigated whether the use of antidepressants is associated with OHCA. METHODS: We conducted a nationwide nested case-control study to assess the association of individual antidepressant drugs within drug classes with the hazard of OHCA. Cases were defined as OHCA from presumed cardiac causes. Cox regression with time-dependent exposure and time-dependent covariates was conducted to calculate hazard ratios (HR) and 95% confidence intervals (95% CIs) overall and in subgroups defined by established cardiac disease and cardiovascular risk factors. Also, we studied antidepressants with and without sodium channel blocking or potassium channel blocking properties separately. RESULTS: During the study period from 2001 to 2015 we observed 10 987 OHCA cases, and found increased OHCA rate for high-dose citalopram (>20 mg) and high-dose escitalopram (>10 mg; HR:1.46 [95% CI:1.27-1.69], HR:1.43 [95% CI:1.16-1.75], respectively) among selective serotonin reuptake inhibitors (reference drug sertraline), and for high-dose mirtazapine (>30; HR:1.59 [95% CI:1.18-2.14]) among the serotonin-norepinephrine reuptake inhibitors or noradrenergic and specific serotonergic antidepressants (reference drug duloxetine). Among tricyclic antidepressants (reference drug amitriptyline), no drug was associated with significantly increased OHCA rate. Increased OHCA rate was found for antidepressants with known potassium channel blocking properties (HR:1.14 [95% CI:1.05-1.23]), but for not those with sodium channel blocking properties. Citalopram, although not statistically significant, and mirtazapine were associated with increased OHCA rate in patients without cardiac disease and cardiovascular risk factors. CONCLUSION: Our findings indicate that careful titration of citalopram, escitalopram and mirtazapine dose may have to be considered due to drug safety issues.