Immunomodulator mediated changes in plasma membrane calcium ATPase in controlling visceral leishmaniasis.

Immunomodulation is an emerging concept to combat infection in recent years. Immunomodulators like arabinosylated-lipoarabinomannan (Ara-LAM) and glycyrrhizic-acid (GA) possess anti-leishmanial property, whereas sodium-antimony-gluconate (SAG) is still considered as the first choice for chemotherapy against leishmaniasis. During infection, invasion of Leishmania donovani needs the potential requirement of Ca2+, which is further responsible for apoptosis in intracellular amastigotes. However, suppression of elevated intracellular calcium by the activation of plasma-membrane-calcium-ATPase (PMCA4) facilitates survival of L. donovani in the host. In the present study, SAG, Ara-LAM, and GA were found to evoke significant increase in intracellular Ca2+ in L. donovani infected macrophages by inhibiting PMCA4. Moreover, PMCA4 inhibition by TFP or PMCA4 siRNA elevated the level of PKCß, whereas calcium-independent upregulation of PKCζ remained unchanged in infected macrophages. Furthermore, application of immunomodulators in infected macrophages resulted in down-regulation of PKCζ, conversion of anti-inflammatory to pro-inflammatory cytokines and inhibition of PMCA4. Plasma membrane-associated ceramide which is known to be elevated during leishmaniasis, triggered upregulation of PMCA4 via PKCζ activation. Interestingly, immunomodulators attenuated ceramide generation, which resulted into reduced PKCζ activation leading to the decreased PMCA expression in infected macrophages. Therefore, our study elucidated the efficacy of SAG, Ara-LAM, and GA in the reduction of parasite burden in macrophages by suppressing PMCA activation through inhibition of ceramide mediated upregulation of PKCζ.

Effects of Covalent Conjugates of Fullerene Derivatives with Xanthene Dyes on Activity of Ca2+-ATPase of the Sarcoplasmic Reticulum.

The effects of the newly synthesized covalent conjugates of water-soluble fullerene derivatives (WSFD) with xanthene dyes: polyanionic WSFD-fluorescein (1), polycationic WSFD-fluorescein (2), polyanionic WSFD-eosin (3), and polyanionic WSFD (4), polycationic WSFD (5), fluorescein (6) and eosin (7), on activity of the membrane-bound Ca2+-ATPase of the sarcoplasmic reticulum (SR Ca2+-ATPase) were studied. Compounds 1, 3, 4, 6, and 7 inhibit the hydrolytic function of the enzyme, the inhibition constants for these compounds are Ki=1.3×10-5 M (1), Ki=4.7×10-6 M (3), Ki=2.5×10-6 M (4), Ki=6.1×10-5 M (6), and Ki=5.8×10-6 M (7). The effects of compounds 3, 6, and 7 on the hydrolytic function of the enzyme is competitive; compounds 1 and 4 are noncompetitive. Polycationic WSFD fluorescein (2) and polycationic WSFD (5) do not affect ATP hydrolysis, but inhibit active Ca2+ transport in a concentration of 0.01 mM by 100±10 and 40±4%, respectively. Conjugates 1 and 3 completely inhibit the hydrolytic and transport functions of the enzyme in a concentration of 0.01 mM, and in a concentration of 0.001 mM inhibit active Ca2+ transport by 60±6 and 55±6% uncoupling the hydrolytic and transport functions of SR Ca2+-ATPases. The obtained results demonstrate a significant effect of the studied compounds on the active transmembrane transfer of Ca2+ and make it possible to predict the presence of antimetastatic and antiaggregatory activities of the studied compounds.

Deletion of the Golgi Ca2+-ATPase PMR1 gene potentiates antifungal effects of dodecanol that depend on intracellular Ca2+ accumulation in budding yeast.

One strategy for overcoming infectious diseases caused by drug-resistant fungi involves combining drugs rendered inactive by resistance with agents targeting the drug resistance mechanism. The antifungal activity of n-dodecanol disappears as incubation time passes. In Saccharomyces cerevisiae, anethole, a principal component of anise oil, prolongs the transient antifungal effect of dodecanol by downregulating genes of multidrug efflux pumps, mainly PDR5. However, the detailed mechanisms of dodecanol's antifungal action and the anethole-induced prolonged antifungal action of dodecanol are unknown. Screening of S. cerevisiae strains lacking genes related to Ca2+ homeostasis and signaling identified a pmr1Δ strain lacking Golgi Ca2+-ATPase as more sensitive to dodecanol than the parental strain. Dodecanol and the dodecanol + anethole combination significantly increased intracellular Ca2+ levels in both strains, but the mutant failed to clear intracellular Ca2+ accumulation. Further, dodecanol and the drug combination reduced PMR1 expression and did not lead to specific localization of Pmr1p in the parental strain after 4-h treatment. By contrast with the parental strain, dodecanol did not stimulate PDR5 expression in pmr1Δ. Based on these observations, we propose that the antifungal activity of dodecanol is related to intracellular Ca2+ accumulation, possibly dependent on PMR1 function, with anethole enabling Ca2+ accumulation by restricting dodecanol efflux.

Disaccharide combinations and the expression of enolase3 and plasma membrane Ca2+ ATPase isoform in sturgeon sperm cryopreservation.

Acipenser sinensis and Acipenser dabryanus are critically endangered species, so germplasm conservation via cryopreservation of sperm is necessary. Disaccharides can act as membrane-impermeable cryoprotectants, and enolase3 (ENO3) and plasma membrane Ca2+ ATPase isoform (PMCA2) are proteins associated with sperm quality. We considered seven characteristics of sperm quality in cultured brood stock from A. sinensis and A. dabryanus. We tested use of sucrose or trehalose alone and in combination at different concentrations for cryopreservation of A. dabryanus sperm. A low concentration of sucrose plus trehalose (S15 T15 ) was optimal. Mixing of the extender with sucrose, lactose, or trehalose alone or with pairwise mixtures revealed that a mixture of lactose and trehalose (L15 T15 ) gave the best results for both A. sinensis and A. dabryanus. Enolase3 and PMCA2 expression levels were measured in cryopreserved A. sinensis sperm via Western blotting. Relative ENO3 and PMCA2 expression levels were examined, and the relationship between disaccharide composition, sperm quality and protein expression was explored in A. sinensis. The results showed that relative ENO3 and PMCA2 expression levels were the highest at L15 T15 in cryopreserved A. sinensis sperm. There were significant positive correlations between ENO3 expression and percentage membrane integrity, and between PMCA2 expression and sperm motility parameters (percentage of motile sperm, curvilinear velocity, straight-line velocity and average path velocity; p < .05) in cryopreserved A. sinensis sperm. Our results indicate the optimal disaccharide combination and concentrations for cryopreservation of A. sinensis and A. dabryanus sperm and suggest that ENO3 and PMCA2 expression levels could serve as a valuable indicator of sperm quality in A. sinensis.

Presence of a thapsigargin-sensitive calcium pump in Trypanosoma evansi: Immunological, physiological, molecular and structural evidences.

In higher eukaryotes, the sarco-endoplasmic reticulum (ER) Ca(2+)-ATPase (SERCA) is characterized for its high sensitivity to low concentrations of thapsigargin (TG), a very specific inhibitor. In contrast, SERCA-like enzymes with different sensitivities to TG have been reported in trypanosomatids. Here, we characterized a SERCA-like enzyme from Trypanosoma evansi and evaluated its interaction with TG. Confocal fluorescence microscopy using BODIPY FL TG and specific anti-SERCA antibodies localized the T. evansi SERCA-like enzyme in the ER and confirmed its direct interaction with TG. Moreover, the use of either 1 µM TG or 25 µM 2',5'-di (tert-butyl)-1,4-benzohydroquinone prevented the reuptake of Ca(2+) and consequently produced a small increase in the parasite cytosolic calcium concentration in a calcium-free medium, which was released from the ER pool. A 3035 bp-sequence coding for a protein with an estimated molecular mass of 110.2 kDa was cloned from T. evansi. The corresponding gene product contained all the invariant residues and conserved motifs found in other P-type ATPases but lacked the calmodulin binding site. Modeling of the three-dimensional structure of the parasite enzyme revealed that the amino acid changes found in the TG-SERCA binding pocket do not compromise the interaction between the enzyme and the inhibitor. Therefore, we concluded that T. evansi possesses a SERCA-like protein that is inhibited by TG.

Impairment of calcium ATPases by high glucose and potential pharmacological protection.

The review deals with impairment of Ca(2+)-ATPases by high glucose or its derivatives in vitro, as well as in human diabetes and experimental animal models. Acute increases in glucose level strongly correlate with oxidative stress. Dysfunction of Ca(2+)-ATPases in diabetic and in some cases even in nondiabetic conditions may result in nitration of and in irreversible modification of cysteine-674. Nonenyzmatic protein glycation might lead to alteration of Ca(2+)-ATPase structure and function contributing to Ca(2+) imbalance and thus may be involved in development of chronic complications of diabetes. The susceptibility to glycation is probably due to the relatively high percentage of lysine and arginine residues at the ATP binding and phosphorylation domains. Reversible glycation may develop into irreversible modifications (advanced glycation end products, AGEs). Sites of SERCA AGEs are depicted in this review. Finally, several mechanisms of prevention of Ca(2+)-pump glycation, and their advantages and disadvantages are discussed.

In vitro sensitivity of Plasmodium falciparum from China-Myanmar border area to major ACT drugs and polymorphisms in potential target genes.

Drug resistance has always been one of the most important impediments to global malaria control. Artemisinin resistance has recently been confirmed in the Greater Mekong Subregion (GMS) and efforts for surveillance and containment are intensified. To determine potential mechanisms of artemisinin resistance and monitor the emergence and spread of resistance in other regions of the GMS, we investigated the in vitro sensitivity of 51 culture-adapted parasite isolates from the China-Myanmar border area to four drugs. The 50% inhibitory concentrations (IC50s) of dihydroartemisinin, mefloquine and lumefantrine were clustered in a relatively narrow, 3- to 6-fold range, whereas the IC50 range of artesunate was 12-fold. We assessed the polymorphisms of candidate resistance genes pfcrt, pfmdr1, pfATP6, pfmdr6 and pfMT (a putative metabolite/drug transporter). The K76T mutation in pfcrt reached fixation in the study parasite population, whereas point mutations in pfmdr1 and pfATP6 had low levels of prevalence. In addition, pfmdr1 gene amplification was not detected. None of the mutations in pfmdr1 and pfATP6 was associated significantly with in vitro sensitivity to artemisinin derivatives. The ABC transporter gene pfmdr6 harbored two point mutations, two indels, and number variations in three simple repeats. Only the length variation in a microsatellite repeat appeared associated with altered sensitivity to dihydroartemisinin. The PfMT gene had two point mutations and one codon deletion; the I30N and N496- both reached high levels of prevalence. However, none of the SNPs or haplotypes in PfMT were correlated significantly with resistance to the four tested drugs. Compared with other parasite populations from the GMS, our studies revealed drastically different genotype and drug sensitivity profiles in parasites from the China-Myanmar border area, where artemisinins have been deployed extensively for over 30 years.

Artemisinins and the biological basis for the PfATP6/SERCA hypothesis.

With the advent of artemisinin resistance, it is timely to revisit the biological basis for the controversial suggestion that this class of antimalarial exerts its activity by inhibiting a calcium ATPase (PfATP6) that is most similar to sarcoplasmic endoplasmic reticulum calcium ATPases (SERCAs). Herein, evidence is discussed that relates to this hypothesis as alternative suggestions for how artemisinins might act have been reviewed elsewhere.

Purified E255L mutant SERCA1a and purified PfATP6 are sensitive to SERCA-type inhibitors but insensitive to artemisinins.

The antimalarial drugs artemisinins have been described as inhibiting Ca(2+)-ATPase activity of PfATP6 (Plasmodium falciparum ATP6) after expression in Xenopus oocytes. Mutation of an amino acid residue in mammalian SERCA1 (Glu(255)) to the equivalent one predicted in PfATP6 (Leu) was reported to induce sensitivity to artemisinin in the oocyte system. However, in the present experiments, we found that artemisinin did not inhibit mammalian SERCA1a E255L either when expressed in COS cells or after purification of the mutant expressed in Saccharomyces cerevisiae. Moreover, we found that PfATP6 after expression and purification from S. cerevisiae was insensitive to artemisinin and significantly less sensitive to thapsigargin and 2,5-di(tert-butyl)-1,4-benzohydroquinone than rabbit SERCA1 but retained higher sensitivity to cyclopiazonic acid, another type of SERCA1 inhibitor. Although mammalian SERCA and purified PfATP6 appear to have different pharmacological profiles, their insensitivity to artemisinins suggests that the mechanism of action of this class of drugs on the calcium metabolism in the intact cell is complex and cannot be ascribed to direct inhibition of PfATP6. Furthermore, the successful purification of PfATP6 affords the opportunity to develop new antimalarials by screening for inhibitors against PfATP6.

Protective effects of Chlorpromazine and Verapamil against cadmium-induced kidney damage in vivo.

Overexposure to cadmium (Cd) can induce kidney damage, which was related to the oxidative damage and disturb intracellular Ca2+ homeostasis. Chlorpromazine (CPZ), targeting calmodulin (CaM), and the Ca2+ channel blocker Verapamil (Ver) are involved in intracellular Ca2+ homeostasis processes. The aim of the study was to investigate the kidney damage caused by Cd administrated for 6 weeks and to evaluate the effects of pre-treatment with either chlorpromazine or verapamil on Cd-induced kidney damage. Thirty-two Wistar rats were divided randomly into 4 groups by weight, i.e., control group, Cd-treated group, and CPZ or Ver pre-treated group. The Cd-treated group rats were subcutaneously (s.c.) injected with 7micromol CdCl2/kg body weight/day. The CPZ and Ver pre-treated group rats were intraperitoneally (i.p.) injected with 5mg CPZ/kg body weight/day, 4mg Ver/kg body weight/day, respectively, 1h before the s.c. administration of 7micromol CdCl2/kg body weight/day. The control group rats were injected s.c. with saline at the same time. The volume of injection was 2ml/kg body weight, 5 times per week, for up to 6 weeks. After 6 weeks, Cd concentrations in the renal cortex and urine were significantly higher in Cd-treated group than that in controls. Cd concentrations of the urine in CPZ and Ver pre-treated groups were significantly lower than that in Cd-treated group, but there were no significant changes in the renal cortex. Compared with the controls, urinary NAG, ALP activities, and the levels of GSH, MDA, and the activities of PKC, Na(+)-K(+)-ATPase, and Ca(2+)-ATPase in rats from the Cd-treated group were significantly increased. SOD activity was suppressed by Cd. Urinary NAG activity and the level of GSH and the activities of PKC and Ca(2+)-ATPase in both CPZ and Ver pre-treated groups were significantly lower than that in Cd-treated rats. The present results showed that Cd-induced kidney damage was related to the oxidative damage and disturb intracellular Ca2+ homeostasis. Both CPZ and Ver possess some ability to prevent cadmium-induced kidney damage via antioxidative action and by maintaining calcium homeostasis.

Methyl tert-butyl ether (MTBE) induced Ca(2+)-dependent cytotoxicity in isolated rabbit tracheal epithelial cells.

As a volatile synthetic organic chemical, methyl tert-butyl ether (MTBE) was the most common gasoline additive. The increasing use of MTBE raised concern over its health safety. Inhalation was the principle route of exposure for the general population. This study used a model of rabbit tracheal epithelial cells (RTEs) in primary culture to investigate the cytotoxic effects induced by MTBE and the potential mechanism. RTEs were incubated with medium alone (control), 0.5, 50, 5000ppm MTBE respectively. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazo liumbromide) assay, staining with fluorescein diacetate, propidium iodide and lactate dehydrogenase leakage ratio were used to assess MTBE cytotoxicity on cells. We also observed a significant elevation in cytosolic Ca2+ by fluorescence probe Fluo-3AM at 3, 6 and 12h following exposure to MTBE. Loss of mitochondrial membrane potential (MMP) was detected following 12 and 24h treatment of NP and assessment by rhodamine 123 (Rh123) staining. Activity changes of the Ca(2+)-ATPase, Ca(2+)-Mg(2+)-ATPase following MTBE treatment displayed a similar trend, suggesting an initial elevation before 6h and subsequent dramatic decrease at 12h. Our results demonstrated that induction of cell injury, associated with mitochondrial dysfunction, and alterations in cytosolic Ca2+ in RTEs represent key mechanisms by which MTBE exerts its cytotoxic effects.

Intracellular calcium dynamics and acetylcholine-induced triggered activity in the pulmonary veins of dogs with pacing-induced heart failure.

BACKGROUND: Heart failure increases autonomic nerve activities and changes intracellular calcium (Ca(i)) dynamics. OBJECTIVE: The purpose of this study was to investigate the hypothesis that abnormal Ca(i) dynamics are responsible for triggered activity in the pulmonary veins (PVs) during acetylcholine infusion in a canine model of heart failure. METHODS: Simultaneous optical mapping of Ca(i) and membrane potential was performed in isolated Langendorff-perfused PV-left atrial (LA) preparations from nine dogs with ventricular pacing-induced heart failure. Mapping was performed at baseline, during acetylcholine (1 micromol/L) infusion (N = 9), and during thapsigargin and ryanodine infusion (N = 6). RESULTS: Acetylcholine abbreviated the action potential. In four tissues, long pauses were followed by elevated diastolic Ca(i), late phase 3 early afterdepolarizations, and atrial fibrillation (AF). The incidence of PV focal discharges during AF was increased by acetylcholine from 2.4 +/- 0.6 beats/s (N = 4) to 6.5 +/- 2.2 beats/s (N = 8; P = .003). PV focal discharge and PV-LA microreentry coexisted in 6 of 9 preparations. The spatial distribution of dominant frequency demonstrated a focal source pattern, with the highest dominant frequency areas colocalized with PV focal discharge sites in 35 (95%) of 37 cholinergic AF episodes (N = 8). Thapsigargin and ryanodine infusion eliminated focal discharges in 6 of 6 preparations and suppressed the inducibility of AF in 4 of 6 preparations. PVs with focal discharge have higher densities of parasympathetic nerves than do PVs without focal discharges (P = .01), and periodic acid-Schiff (PAS)-positive cells were present at the focal discharge sites. CONCLUSION: Ca(i) dynamics are important in promoting triggered activity during acetylcholine infusion in PVs from pacing-induced heart failure. PV focal discharge sites have PAS-positive cells and high densities of parasympathetic nerves.

Beneficial influence of capsaicin on lipid peroxidation, membrane-bound enzymes and glycoprotein profile during experimental lung carcinogenesis.

This study was designed to examine the impact of a principal component of hot red peppers and chilli peppers, capsaicin, on alterations in lipid peroxidation, membrane-bound enzyme profiles and glycoprotein levels during benzo(a)pyrene (BP)-induced lung cancer in Swiss albino mice. BP (50 mgkg(-1)) induced deleterious changes that were that revealed by alterations in lipid peroxidation, membrane-bound enzyme (Na+/K+ ATPase, Ca2+ ATPase and Mg2+ ATPase) activity, levels of total protein and protein-bound carbohydrate components (sialic acid, hexose, hexosamine, hexuronic acid and fucose). Pre-co-treatment with capsaicin (10 mg kg(-1)) restored the detrimental effects induced by BP, indicating its protective role in BP-induced lung cancer.

Lusitropic effects of dobutamine in young and aged mice in vivo.

Aged individuals have impaired diastolic relaxation-lusitropic function. Dobutamine, a selective B1-adrenergic agonist, is used to augment systolic cardiac function at the termination of cardiopulmonary bypass (CPB). However, our question is whether dobutamine will also enhance the lusitropic function in the aged individual. The myocyte mechanism for the rate of ventricular relaxation is dependent on the velocity of calcium removal from the myocyte contractile elements by sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a), which is regulated by an inhibitory protein, phospholamban (PLB). Ventricular tissues harvested from young (4 month) and aged (20 months) mice were analyzed to compare the protein levels of SERCA2a and PLB with immunoblot and gene expression for PLB with reverse-transcriptase-polymerase chain reaction. The molecular analyses were compared with in vivo left ventricular function in the young and old mice before and during an intravenous infusion of dobutamine (5 microg/kg/min). The SERCA2a levels were not different between the groups; however, there was a 2-fold increase in PLB in the aged group compared with the young group (p < .05). The gene expression for PLB was increased by 5-fold in the aged group compared with the young group (p < .01). There were significant differences between the young and aged groups related to the lusitropic parameters, tau and dP/dt(min), and dobutamine infusion increased these parameters in the aged group to that of the young group. This report supports the concept that altered PLB levels correspond with the respective lusitropic function and that dobutamine administration in the aged group increased lusitropic function that was comparable with the young group. Because the patient population requiring CPB is aging, these data suggest that the use of dobutamine at the terminal phase of CPB is warranted to increase systolic and diastolic function.

Age-associated alterations of lipofuscin, membrane-bound ATPases and intracellular calcium in cortex, striatum and hippocampus of rat brain: protective role of glutathione monoester.

Brain aging has become an area of intense research and a subject of much speculation fueled largely from the widely recognized fact that age is the biggest risk factor in most neurodegenerative diseases and age-related increase of reactive oxygen species is particularly detrimental to postmitotic tissues. In the present study, we have evaluated the possible role of glutathione monoester (GME), when administered intraperitoneally (12mg/kg body weight) for 20 days on age-associated changes in the levels of lipofuscin, Na+K+, Mg2+, Ca2+ ATPase activities and intracellular calcium levels in discrete brain regions of young and aged male albino Wistar rats. An age-associated increase in lipofuscin, intracellular calcium in cortex, striatum and hippocampus was observed and contradictorily, a decrease in the activities of membrane-bound enzyme activities was also observed. Supplementation of GME brought these changes to near normalcy. Thus, GME improves neuronal antioxidant status, thereby effectively attenuating any putative increase in oxidative stress with age.

Antiplatelet activity of epigallocatechin gallate is mediated by the inhibition of PLCgamma2 phosphorylation, elevation of PGD2 production, and maintaining calcium-ATPase activity.

We have previously reported that green tea catechins displayed a potent antithrombotic effect by inhibition of platelet aggregation. In the present study, the antiplatelet and antithrombotic activities of epigallocatechin gallate (EGCG), the major catechin derived from green tea, were extensively investigated. EGCG inhibited arterial thrombus formation and U46619-, collagen-, and arachidonic acid (AA)-induced washed rabbit platelet aggregation in a concentration-dependent manner, with IC50 values of 61 +/- 3, 85 +/- 4, and 99 +/- 4 microM, respectively. In line with the inhibition of collagen-induced platelet aggregation, EGCG revealed blocking of the collagen-mediated phospholipase (PL) Cgamma2 and protein tyrosine phosphorylation, and it caused concentration-dependent decreases of cytosolic calcium mobilization, AA liberation, and serotonin secretion. In addition, the platelet aggregation, intracellular Ca2+ mobilization, and protein tyrosine phosphorylation induced by thapsigargin, a Ca2(+)-ATPase pump inhibitor, were completely blocked by EGCG. Contrary to the inhibition of AA-induced platelet aggregation, EGCG failed to inhibit cyclooxygenase and thromboxane (TX) A2 synthase activities, but it concentration-dependently elevated AA-mediated PGD2 formation. In contrast, epigallocatechin (EGC), a structural analogue of EGCG lacking a galloyl group in the 3' position, slightly inhibited collagen-stimulated cytosolic calcium mobilization, but failed to affect other signal transductions as did EGCG in activated platelets and arterial thrombus formation. These results suggest that antiplatelet activity of EGCG may be attributable to its modulation of multiple cellular targets, such as inhibitions of PLCgamma2, protein tyrosine phosphorylation and AA liberation, and elevation of cellular PGD2 levels, as well as maintaining Ca2(+)-ATPase activity, which may underlie its beneficial effect on the atherothrombotic diseases.

Effects of resveratrol on calcium regulation in rats with severe acute pancreatitis.

Intracellular calcium overload plays a key role in severe acute pancreatitis. Resveratrol can decrease the severity of pancreatitis; however, the mechanism of action of resveratrol has not been determined. The aim of our study was to examine the relationship between calcium overload and the effects of resveratrol in severe acute pancreatitis. Animals were randomly divided into 3 groups: control group (sham operation), model group (0.1 ml/100 g of 3.5% sodium taurocholate used to induce severe acute pancreatitis), and treated group (treated with resveratrol, 10 mg/kg). In model group, the severity of pancreatitis was aggravated; this was evaluated by pancreatic weight/body weight and lung weight/body weight ratios, serum amylase activities, and pancreatic histopathological scoring; the Ca(2+)-Mg(2+)-ATPase and Ca(2+)-ATPase activities decreased while PLA(2) activity and [Ca(2+)](i) increased gradually with time. Compared to the control group, in the model group, these changes were observed in the pancreatic tissue at the 3 h time point and in the lung tissue at the 6 h time point. Resveratrol ameliorated the changes in the laboratory parameters and significantly reduced the pathological damage in the tissues at the corresponding time points. In conclusion, intracellular calcium overload leads to tissue damage in severe acute pancreatitis, and the beneficial effects of resveratrol appear to be mediated by reducing the intracellular calcium overload; this not only limits pancreatic cellular injury but also secondary lung injury.

[The complex adaptogenic drug tonizid attenuates myocardial contractile dysfunction and prevents irreversible cardiomyocytic damages in ischemia and reperfusion of the isolated heart].

A course administration of the complex plant adaptogenic drug tonizid was ascertained to increase murine exercise tolerance. In addition, the drug increased murine survival during hypobaric hypoxia (at an altitude of 10,500 m upon 20-min exposure). A model of total 35-min ischemia and that of 30-min reperfusion of the rat isolated heart were used by the Langendorff technique. The course administration of tonizid attenuated a reperfusion decrease in the left ventricular pressure and in the rate of contraction. However, tonizid did not prevent a reperfusion reduction in heart rate, a decrease in the rate of relaxation and an elevation of end diastolic pressure. Tonizid lowered the level of creatine kinase in the venous effluent from the isolated rat heart during reperfusion. At the same time, the plant adaptogen exerted no effect on the incidence of ventricular arrhythmias and coronary flow. It has been suggested that tonizid is an adaptogenic drug that attenuates contractile dysfunction and prevents irreversible cardiomyocytic damage during ischemia and reperfusion of the isolated heart.

[Effect of Cu2+ and Zn2+ ions in Ca-ATPase activity isolated from Pachymerus nucleorum (Fabricius) (Coleoptera: Chrysomelidae, Bruchinae) larvae]. / Efeito de íons Cu2+ e Zn2+ em atividade Ca-ATPásica isolada de larvas de Pachymerus nucleorum (Fabricius) (Coleoptera: Chrysomelidae, Bruchinae).

ATPases, an important target of insecticides, are enzymes that hydrolyze ATP and use the energy released in that process to accomplish some type of cellular work. Pachymerus nucleorum (Fabricius) larvae possess an ATPase, that presents high Ca-ATPase activity, but no Mg-ATPase activity. In the present study, the effect of zinc and copper ions in the activity Ca-ATPase of that enzyme was tested. More than 90% of the Ca-ATPase activity was inhibited in 0.5 mM of copper ions or 0.25 mM of zinc ions. In the presence of EDTA, but not in the absence, the inhibition by zinc was reverted with the increase of calcium concentration. The inhibition by copper ions was not reverted in the presence or absence of EDTA. The Ca-ATPase was not inhibited by treatment of the ATPase fraction with copper, suggesting that the copper ion does not bind directly to the enzyme. The results suggest that zinc and copper ions form a complex with ATP and bind to the enzyme inhibiting its Ca-ATPase activity.