Effect of trimetazidine on serum interleukin-6 and C-reactive protein concentrations in patients with stable coronary artery disease.

Trimetazidine is widely used in the treatment of stable coronary artery disease (CAD) and its cytoprotective effect has been confirmed in animal studies and in many clinical trials. Given the inflammatory milieu of CAD and trimetazidine effect on the inflow of neutrophilis to the ischemic area, it is interesting to consider whether trimetazidine actions could be also explained through the inhibition of inflammatory mediators, including cytokines. The aim of this study was to (i) examine the influence of treadmill exercise test (TET) on serum C-reactive protein (CRP) and interleukin-6 (IL-6), and (ii) the influence of three-month trimetazidine therapy on serum CRP and IL-6 concentrations. One hundred and fifty-six patients with stable CAD were included. TET was performed (according to the standard Bruce protocol) twice for all subjects – at baseline and after the three-month trimetazidine treatment. Serum IL-6 and CRP concentrations were determined prior to and after performing each TET. Exercise led to the increase of CRP (2.35 vs 2.81 mg/L, p < 0.05) and IL-6 concentrations (1.64 vs 1.92 pg/ml, p=0.0318) in patients without trimetazidine. Three-month treatment resulted in the increase in the TET duration (378.0s vs 410.9s, p < 0.05) and decrease in serum CRP concentration, both before (2.35 vs 1.51 mg/L, p < 0.05) and after TET (2.81 vs 1.69 mg/L, p < 0.05). There was no significant increase of CRP after the second TET (1.51 vs 1.69 mg/l, p=NS). Three-month trimetazidine treatment increased IL-6 concentrations (1.64 vs 2.23 pg/mL, p < 0.05). TET was not associated with further changes in IL-6 concentrations (2.23 vs 2.18 pg/mL, p=NS). Serum IL-6 and CRP concentrations increase during exercise in patients without trimetazidine. Three-month trimetazidine prolonged the duration of TET. Moreover, it resulted in the reduction of CRP concentration The increase of IL-6 concentration after three-month trimetazidine treatment and the lack of changes of its concentration after TET is associated with yet another mechanism of trimetazidine.

Remote mental health care interventions during the COVID-19 pandemic: An umbrella review.

Mitigating the COVID-19 related disruptions in mental health care services is crucial in a time of increased mental health disorders. Numerous reviews have been conducted on the process of implementing technology-based mental health care during the pandemic. The research question of this umbrella review was to examine what the impact of COVID-19 was on access and delivery of mental health services and how mental health services have changed during the pandemic. A systematic search for systematic reviews and meta-analyses was conducted up to August 12, 2022, and 38 systematic reviews were identified. Main disruptions during COVID-19 were reduced access to outpatient mental health care and reduced admissions and earlier discharge from inpatient care. In response, synchronous telemental health tools such as videoconferencing were used to provide remote care similar to pre-COVID care, and to a lesser extent asynchronous virtual mental health tools such as apps. Implementation of synchronous tools were facilitated by time-efficiency and flexibility during the pandemic but there was a lack of accessibility for specific vulnerable populations. Main barriers among practitioners and patients to use digital mental health tools were poor technological literacy, particularly when preexisting inequalities existed, and beliefs about reduced therapeutic alliance particularly in case of severe mental disorders. Absence of organizational support for technological implementation of digital mental health interventions due to inadequate IT infrastructure, lack of funding, as well as lack of privacy and safety, challenged implementation during COVID-19. Reviews were of low to moderate quality, covered heterogeneously designed primary studies and lacked findings of implementation in low- and middle-income countries. These gaps in the evidence were particularly prevalent in studies conducted early in the pandemic. This umbrella review shows that during the COVID-19 pandemic, practitioners and mental health care institutions mainly used synchronous telemental health tools, and to a lesser degree asynchronous tools to enable continued access to mental health care for patients. Numerous barriers to these tools were identified, and call for further improvements. In addition, more high quality research into comparative effectiveness and working mechanisms may improve scalability of mental health care in general and in future infectious disease outbreaks.

Phase I dose-escalation single centre clinical trial to evaluate the safety of infusion of memory T cells as adoptive therapy in COVID-19 (RELEASE).

BACKGROUND: Effective treatments are still needed to reduce the severity of symptoms, time of hospitalization, and mortality of COVID-19. SARS-CoV-2 specific memory T-lymphocytes obtained from convalescent donors recovered can be used as passive cell immunotherapy. METHODS: Between September and November 2020 a phase 1, dose-escalation, single centre clinical trial was conducted to evaluate the safety and feasibility of the infusion of CD45RA- memory T cells containing SARS-CoV-2 specific T cells as adoptive cell therapy against moderate/severe cases of COVID-19. Nine participants with pneumonia and/or lymphopenia and with at least one human leukocyte antigen (HLA) match with the donor were infused. The first three subjects received the lowest dose (1 × 105 cells/kg), the next three received the intermediate dose (5 × 105 cells/kg) and the last three received the highest dose (1 × 106 cells/kg) of CD45RA- memory T cells. Clinicaltrials.gov registration: NCT04578210. FINDINGS: All participants' clinical status measured by National Early Warning Score (NEWS) and 7-category point ordinal scales showed improvement six days after infusion. No serious adverse events were reported. Inflammatory parameters were stabilised post-infusion and the participants showed lymphocyte recovery two weeks after the procedure. Donor microchimerism was observed at least for three weeks after infusion in all patients. INTERPRETATION: This study provides preliminary evidence supporting the idea that treatment of COVID-19 patients with moderate/severe symptoms using convalescent CD45RA- memory T cells is feasible and safe. FUNDING: Clinical Trial supported by Spanish Clinical Research Network PT17/0017/0013. Co-funded by European Regional Development Fund/European Social Fund. CRIS CANCER Foundation Grant to AP-M and Agencia Valenciana de Innovación Grant AVI-GVA COVID-19-68 to BS.

Serum concentration of insulin-like growth factor-I, but not tumor necrosis factor-alpha, measured twelve months after stenting of the infarct-related artery, is associated with in-stent restenosis.

Percutaneous coronary intervention (PCI) has revolutionized the management of and outcomes in patients with ST-segment elevation myocardial infarction (STEMI). The role of insulin-like growth factor-I (IGF-I) and tumor necrosis factor-alpha (TNF-alpha) in restenosis has been intensively studied. We aimed to investigate the power of serum IGF-I and TNF-alpha concentrations to predict restenosis in patients who had previously undergone PCI for STEMI. Thirty-seven patients were enrolled in the study. Twelve months prior to the study they underwent successful PCI with stent placement for STEMI. The patients were divided into two groups: group 1 - patients with in-stent restenosis in the infarct-related artery (N=9); group 2 - patients without in-stent restenosis in the infarct-related artery (N=28). Baseline profile was similar in both groups. The mean diameter and length of placed stents were similar in both groups. Smaller minimal lumen diameter (MLD) and greater lumen loss (LL) were observed in group 1. Median IGF-I concentrations were substantially higher in patients with ISR compared to those without ISR (170 ng/mL vs 115 ng/mL, p=0.004). Strikingly, median TNF-alpha levels were lower in group 1 (2.4 pg/mL vs 4.1 pg/mL, p=0.05). Correlation analysis showed that serum IGF-I levels were significantly associated with diameter stenosis (R=0.29 p=0.05), LL (R=0.37 p=0.02), MLD (R= -0.38 p=0.03), and stent length (R=0.30 p=0.05). The cut-off value to predict restenosis for IGF-I was less than 158 ng/mL (sensitivity 55 percent, specificity 93 percent, positive predictive value 71 percent, negative predictive value 87 percent). IGF-I detected twelve months after stent placement during the acute phase of AMI may be a late determinant of restenosis. High concentrations of IGF-I could play a permissive role in the progression of NIH and subsequently restenosis. It seems that as far as TNF-alpha is concerned, diagnostic value remains inconclusive.

Evidence for the involvement of the kainate receptor subunit GluR6 (GRIK2) in mediating behavioral displays related to behavioral symptoms of mania.

The glutamate receptor 6 (GluR6 or GRIK2, one of the kainate receptors) gene resides in a genetic linkage region (6q21) associated with bipolar disorder (BPD), but its function in affective regulation is unknown. Compared with wild-type (WT) and GluR5 knockout (KO) mice, GluR6 KO mice were more active in multiple tests and super responsive to amphetamine. In a battery of specific tests, GluR6 KO mice also exhibited less anxious or more risk-taking type behavior and less despair-type manifestations, and they also had more aggressive displays. Chronic treatment with lithium, a classic antimanic mood stabilizer, reduced hyperactivity, aggressive displays and some risk-taking type behavior in GluR6 KO mice. Hippocampal and prefrontal cortical membrane levels of GluR5 and KA-2 receptors were decreased in GluR6 KO mice, and chronic lithium treatment did not affect these decreases. The membrane levels of other glutamatergic receptors were not significantly altered by GluR6 ablation or chronic lithium treatment. Together, these biochemical and behavioral results suggest a unique role for GluR6 in controlling abnormalities related to the behavioral symptoms of mania, such as hyperactivity or psychomotor agitation, aggressiveness, driven or increased goal-directed pursuits, risk taking and supersensitivity to psychostimulants. Whether GluR6 perturbation is involved in the mood elevation or thought disturbance of mania and the cyclicity of BPD are unknown. The molecular mechanism underlying the behavioral effects of lithium in GluR6 KO mice remains to be elucidated.

The role of interleukin-6 and transforming growth factor-beta1 in predicting restenosis within stented infarct-related artery.

Despite high efficacy of percutaneous coronary intervention (PCI), in-stent restenosis proves to be a significant problem of therapy. Restenosis concerns around 30 percent of patients. Studies have suggested that restenosis is initiated by cells which participate in intense inflammatory reaction caused by stent implantation. Atherosclerotic plaque rupture during stent implantation and PCI-associated injury of the vessel wall lead to hemorrhage and release of various cytokines. They are probably responsible for quick recurrence of vascular lumen stenosis (restenosis). Interleukin-6 (IL-6) is known as a main pro-inflammatory cytokine, whereas Transformig Growth Factor-beta1 (TGF-beta1) has anti-inflammatory properties. The study population comprised 36 patients with myocardial infarction treated with PCI with stent implantation. They underwent control coronary angiography after 12 months. At this time plasma concentration of IL-6 and TGF-beta was measured in peripheral blood. Serum IL-6 concentration in the analyzed population correlates with lumen loss (p<0.01) and the severity of stenosis (p<0.001). No such correlation was found between serum TGF-beta1 concentration and lumen loss (p=NS) or the severity of stenosis (p=NS). The IL-6 plasma concentration may be a marker of in-stent restenosis in patients after PTCA, while the concentration of TGF-beta1 is not associated with the occurrence of restenosis at one year of follow-up.

The dopamine D3/D2 agonist (+)-PD-128,907 [(R-(+)-trans-3,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1,4-oxazin-9-ol)] protects against acute and cocaine-kindled seizures in mice: further evidence for the involvement of D3 receptors.

Previous findings have demonstrated a protective role for dopamine D(3)/D(2) receptor agonists in the convulsant and lethal effects of acutely administered cocaine. Data are provided here to establish that the protection occurs through a D(3)-linked mechanism and that protection is extended to seizure kindling. The D(3) antagonist SB-277011-A [4-quinolinecarboxamide,N-[trans-4-[2-(6-cyano-3,4-dihydro-2(1H)-isoquinolinyl)ethyl]-cyclohexyl]-(9CI)] prevented the anticonvulsant effect of the D(3)/D(2) receptor agonist (+)-PD-128,907 [(R-(+)-trans-3,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1,4-oxazin-9-ol)] on cocaine-induced seizures. The protection afforded by the D(3)/D(2) agonist, (+)-PD-128,907, was eliminated in D(3) receptor-deficient mice. In D(2) receptor knockout mice, the anticonvulsant effects of (+)-PD-128,907 were preserved. (+)-PD-128,907 also prevented the acquisition and expression of cocaine-kindled seizures engendered by repeated daily dosing with 60 mg/kg cocaine. (+)-PD-128,907 also blocked the seizures induced in mice fully seizure kindled to cocaine. Although repeated dosing with cocaine increased the potency of cocaine to produce seizures and lethality (decreased ED(50) values), daily coadministration of (+)-PD-128,907 significantly prevented this potency shift. In mice treated daily with cocaine and (+)-PD-128,907, the density, but not the affinity, of D(3) receptors was increased. The specificity with which (+)-PD-128,907 acts upon this cocaine-driven process was demonstrated by the lack of a significant effect of (+)-PD-128,907 on seizure kindling to a GABA(A) receptor antagonist, pentylenetetrazol. Taken together and with literature findings, the data indicate that dopamine D(3) receptors function in the initiation of a dampening mechanism against the toxic effects of cocaine, a finding that might have relevance to psychiatric disorders of drug dependence, schizophrenia, and bipolar depression.

Role of Pro-Brain Natriuretic Peptide Serum Concentration in the Detection of Pulmonary Hypertension in Patients With End-Stage Lung Diseases Referred for Lung Transplantation.

BACKGROUND: Serum N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration is elevated in patients with pulmonary hypertension (PH); however, its role in the detection of PH associated with lung disease is not well established. AIM: The aim of this study was to assess the value of NT-proBNP in the detection of PH in patients with end-stage lung disease (esLD) referred for lung transplantation. MATERIALS AND METHODS: The study population consisted of 65 patients: 37 with idiopathic pulmonary fibrosis (IPF), 20 with chronic obstructive pulmonary disease, and 8 patients with other interstitial lung diseases (75% men, mean age 53.3 ± 9.5 years). Serum concentration of NT-proBNP was assessed with an immunoradiometric assay kit. The mean pulmonary artery pressure (mPAP) was measured using a Swan-Ganz catheter. PH was defined as mPAP ≥ 25 mm Hg. RESULTS: Median NT-proBNP concentrations were significantly higher in patients with PH than in patients without PH: 139 (49-1236) pg/mL vs 67 (38-116) pg/mL, respectively; P = .016. Receiver operating characteristic (ROC) analysis revealed that NT-proBNP concentration higher than 131.5 pg/mL was a predictor of PH with good specificity (81%) and positive predictive value (78.9%) but low sensitivity (55.6%) and negative predictive value (58.6%). The area under the ROC curve of serum NT-proBNP concentration for PH was 0.71 (95% confidence interval 0.57-0.85, P = .039). CONCLUSION: Serum concentration of NT-proBNP may be useful in the diagnosis of PH in patients with esLD referred for lung transplantation.

Red Blood Cell Distribution Width in End-Stage Heart Failure Patients Is Independently Associated With All-Cause Mortality After Orthotopic Heart Transplantation.

BACKGROUND: Red blood cell markers (RBCM) have been found to be predictors of mortality in various populations. However, there is no information regarding the association between the values of RBCM and long-term outcomes after orthotopic heart transplantation (OHT). The aim of this study was to assess whether the values of inflammatory markers and RBCM obtained directly before OHT are associated with mortality in patients diagnosed as having end-stage heart failure undergoing OHT. METHODS: We retrospectively analyzed data of 173 nonanemic adult patients diagnosed as having end-stage heart failure undergoing primary OHT between 2007 and 2014. Clinical and laboratory data were obtained at the time of admission for the OHT. RBCM were analyzed using an automated blood counter (Sysmex XS-1000i and XE-2100, Sysmex Corporation, Kobe, Japan). RESULTS: Mean age of the patients was 54 (41-59) and 72% of them were male. During the observation period, the mortality rate was 32%. Multivariable analysis of Cox proportional hazard confirmed that elevated pretransplantation red blood cell distribution width value (hazard ratio [HR], 1.38 [1.25-1.48], P < .001) was the sole independent predictor of death during long-term follow-up. Other red blood cell distribution width such as mean corpuscular volume, mean corpuscular hemoglobin concentration, and mean corpuscular hemoglobin (HR, 0.88 [0.84-0.91]; P < .001; HR, 0.75 [0.53-1.05]; P < .05; HR, 0.78 [0.64-0.96]; P < .05, respectively) had predictive value in univariable analysis. CONCLUSIONS: In summary, we have demonstrated that elevated red blood cell distribution width immediately before OHT is an independent predictor of all-cause mortality in heart transplant recipients. Other factors associated with posttransplantation mortality include lower values of mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration.

Prognostic Value of Mean, Diastolic, and Systolic Pulmonary Artery Pressure in Patients With End-stage Lung Disease Referred for Lung Transplantation.

BACKGROUND: Pulmonary hypertension (PH) is a common complication in end-stage lung disease (esLD). The aim of this study was to establish the best threshold values for mean, systolic, and diastolic artery pressure (mPAP, dPAP, and sPAP, respectively) to identify patients with esLD referred for lung transplantation and to predict 1-year prognosis. METHODS: Sixty-five patients were enrolled in the study (75% men) with a mean age of 53.3 ± 9.5 years; 31% had chronic obstructive pulmonary disease (COPD), 57% had idiopathic pulmonary fibrosis (IPF), and 12% had interstitial lung diseases (ILDs). The mean period of observation was 14.4 ± 5 months. We assessed invasively mPAP, dPAP, and sPAP, as well as pulmonary capillary wedge pressure (PCWP), using a Swan-Ganz catheter. Receiver-operating characteristic (ROC) curves were constructed to identify the best cutoff points for mPAP, dPAP, and sPAP to predict survival. The study endpoint was defined as 1-year mortality before transplantation. Survival analysis was completed according to the Kaplan-Meier method. RESULTS: During follow-up, 30 (46.1%) patients died and 19 (29%) underwent lung transplantation. Based on ROC curve analysis, we estimated mPAP ≥30 mm Hg, dPAP ≥20 mm Hg, and sPAP ≥44 mm Hg as the best threshold values with the highest sensitivity (70%, 70%, and 73%, respectively) and specificity (76%, 69%, and 72%, respectively) and the acceptable area under curve (0.67, 0.68, and 0.72, respectively). The negative predictive values for mPAP, dPAP, and sPAP were higher than the positive predictive values (79%, 77%, and 81% vs 67%, 61%, and 64%, respectively). We also constructed Kaplan-Meier curves for mPAP, dPAP, and sPAP threshold values. There were significant differences in 1-year survival between patients with and without PH for mPAP, dPAP, and sPAP threshold values (P = .005, P = .035, and P < .001; respectively). CONCLUSION: Elevated mPAP, dPAP, and sPAP are related to worse prognosis in patients with esLD referred for lung transplantation.

Predictive Value of the Model for End-Stage Liver Disease Score Excluding International Normalized Ratio One Year After Orthotopic Heart Transplantation.

BACKGROUND: The Model for End-Stage Liver Disease (MELD) scoring system incorporating a combination of hepatic and renal laboratory parameters does not adequately reflect the degree of multi-organ dysfunction in patients with heart failure, who need oral anticoagulation. In order to exclude the impact of oral anticoagulation on the international normalized ratio (INR), we used the MELD excluding INR (MELD-XI) score. The aims of the study were to calculate the individual preoperative MELD-XI score and its ability to predict 1-year mortality after heart transplantation and to identify other preoperative laboratory prognostic parameters. METHODS: We retrospectively analysed data of 87 consecutive adults undergoing heart transplantation between 2011 and 2014. Clinical data and laboratory parameters for the calculation of the MELD-XI score were obtained at the time of admission for the heart transplantation. RESULTS: The average age of the patients was 48.8 ± 13.3 years and 68.9% of them were male. During the observation period, the mortality rate was 18.4%. Multivariate analysis of Cox proportional hazard confirmed that the pretransplantation MELD-XI score (hazard ratio [HR] = 1.625 [1.286-2.053]; P < .001), sodium serum concentration (HR = 0.824 [0.677-1.001]; P < .05) and highly sensitive C-reactive protein (hs-CRP) serum concentration (HR = 1.045 [1.008-1.083]; P < .02) were independent predictors of death during the first year after heart transplantation. Area under the receiver operating characteristic (ROC) curve (AUC) indicated a good discriminatory power of MELD-XI (AUC 0.997; P < .04) and plasma sodium concentration (AUC 0.901; P < .01) in death prediction. CONCLUSIONS: Our study confirms that the pretransplantation MELD-XI score, as well as serum sodium and hsCRP concentrations, may be used to estimate postoperative risk in heart transplant recipients during a 1-year follow-up.

Perioperative Risk Factors of Cardiac Allograft Vasculopathy in the Long-Term Follow-up.

BACKGROUND: Cardiac allograft vasculopathy (CAV) still remains to be one of the most important limiting factors for heart transplant recipients' long-term survival. The aim of our study was to identify the perioperative risk factors impacting the occurrence of CAV during the long-term follow-up. METHODS: We retrospectively analysed the data from 198 consecutive adult patients, who underwent heart transplantation between 2007 and 2012, in whom at least one routine coronarography (CAG) was performed. CAV onset was defined as any lesion seen at least at one routine CAG. RESULTS: The average follow-up was 63.6 ± 14.7 months. The frequency of CAV in the analysed population was 36 (18.1%). Multivariate stepwise logistic regression analysis confirmed that NT-proBNP plasma concentration directly before heart transplant [logNT-proBNP OR = 16.455 (4.587-31.036), P < .0001], fibrinogen plasma concentration a month after heart transplant [OR = 1.022 (1.009-1.035), P < .001] and occurrence of diabetes [OR = 12.355 (1.417-35.750), P < .001], were independent predictors of CAV. Area under the ROC curves (AUC) indicated a well discriminatory power of plasma fibrinogen [AUC 0.9278, P < .001] and plasma NTproBNP concentration [AUC 0.9514, P < .001] in CAV prediction. The optimal cut-off value of fibrinogen was 509 mg/dL, and of NT-proBNP was 10080 pg/mL. CONCLUSIONS: Our data show that NT-proBNP and fibrinogen plasma concentrations as well as occurence of diabetes, both preexisting and new onset after heart transplant can be used to identify patients at risk of developing CAV.

Predictive Value of Hepatic and Renal Dysfunction Based on the Models for End-Stage Liver Disease in Patients With Heart Failure Evaluated for Heart Transplant.

BACKGROUND: The evaluation of prognosis and determination of a long-term treatment strategy is an important element of management in patients with heart failure (HF). METHODS: The aim of the study was to determine the prognostic value of the Model for End-Stage Liver Disease (MELD) and its modifications, MELD and serum sodium (MELD-Na) and MELD excluding the international normalized ratio (MELD-XI), as well as other independent risk factors for death during a 4-year follow-up. We analyzed retrospectively 143 patients with advanced HF, evaluated for heart transplant between 2009 and 2011. Patients using warfarin were excluded from the study. The long-term follow-up data were obtained during follow-up visits and/or phone contact with the patients or their families. RESULTS: The age of the patients was 54 (48-59) years and 88.1% of patients were male. Mortality rate during the follow-up period was 49%. The MELD scores (hazard ratio [HR], 1.12; P < .001), as well as serum high-sensitivity C-reactive protein (hs-CRP; HR, 1.01; P < .01) and N-terminal pro-brain natriuretic peptide (NT-proBNP; HR, 1.01; P < .05) levels, were independent risk factors for death. Receiver operator characteristic analysis indicated that a MELD cutoff of 10 (area under the curve [AUC], 0.756; P < .0001], MELD-XI cutoff of 13.0 (AUC, 0.720; P < .0001), MELD-Na cutoff of 13.0 (AUC, 0.813; P < .0001), hs-CRP cutoff of 4.02 (AUC, 0.686; P < .001), and NT-proBNP cutoff of 1055 (AUC, 0.722; P < .001) were the best predictive values as predictors of death. CONCLUSIONS: MELD, MELD-Na, and MELD-XI scores are prognostic factors for death during a 4-year follow-up. A high MELD score is an independent prognostic factor for death. NT-proBNP and hs-CRP serum concentrations are other independent factors influencing death.

Neuroactive steroids: potential therapeutic use in neurological and psychiatric disorders.

Neuroactive steroids are a novel class of positive allosteric modulators of the GABAA receptor. Although neuroactive steroids are endogenous neuronal modulators, synthetic entities with improved oral bioavailability have recently been developed. These compounds demonstrate efficacy as anticonvulsants against a range of convulsant stimuli and demonstrate anti-epileptogenic activity in a kindling model of epilepsy. Efficacy has also been reported in preclinical models of anxiety, insomnia, migraine and drug dependence. Clinical evidence to date is generally supportive of these findings and indicates that neuroactive steroids are generally well tolerated. Taken as a whole, current data suggest that neuroactive steroids could have a future role in clinical practice. In this article, Maciej Gasior, Richard Carter and Jeffrey Witkin review preclinical and clinical evidence that forms the basis for predicting the potential therapeutic application of neuroactive steroids.

Influence of BAY k-8644, a calcium channel agonist, on the anticonvulsant activity of conventional anti-epileptics against electroconvulsions in mice.

BAY k-8644, an agonist at the dihydropyridine binding site of the L-type voltage dependent calcium channel, at the dose of 5 mg/kg (s.c.) did not significantly affect the threshold for electroconvulsions, but impaired the protective efficacy of flunarizine (15 and 20 mg/kg, i.p.) in the electroconvulsive test. Interestingly, the calcium channel agonist (at 1 and 5 mg/kg) distinctly diminished the protection offered by conventional anti-epileptic drugs (carbamazepine, diphenylhydantoin and phenobarbital) against maximal electroshock-induced seizures in mice. A pharmacokinetic interaction does not seem to be involved in the effect of BAY k-8644, since total plasma levels of these anti-epileptics (measured by immunofluorescence) were not affected by the calcium channel agonist. The only anti-epileptic drug resistant to BAY k-8644 (up to 5 mg/kg) was valproate, whose ED50 (in mg/kg) was not changed in the presence of the calcium channel agonist. Further, BAY k-8644 (5 mg/kg) did not influence the flunarizine (a calcium channel blocker)-induced potentiation of the protective action of valproate against maximal electroshock-induced convulsions. The calcium channel agonist (5 mg/kg) reversed the flunarizine-induced augmentation of the anticonvulsive activity of carbamazepine. It may be concluded that carbamazepine, diphenylhydantoin and phenobarbital partially exert their anticonvulsive effects via blockade of calcium influx whilst valproate does not seem to. In this context, the flunarizine-induced potentiation of the anticonvulsive activity of valproate is probably independent of calcium channel blockade.

Influence of flunarizine, nicardipine and nimodipine on the anticonvulsant activity of different antiepileptic drugs in mice.

Only flunarizine (40 mg/kg, i.p.) significantly raised the threshold for electroconvulsions in mice (ear-clip electrodes, 0.2 sec stimulus duration, tonic hindlimb extension as an endpoint), whilst nicardipine and nimodipine (up to 80 mg/kg) was ineffective in this respect. Further, flunarizine (10 and 20 mg/kg) potentiated the efficacy of carbamazepine and valproate against maximum electroshock (50 mA)-induced seizures and, in the dose of 20 mg/kg, enhanced that of diphenylhydantoin. In addition, this calcium channel inhibitor was without influence upon the total levels of these antiepileptics in plasma. Nicardipine (5 and 10 mg/kg) and nimodipine (10 and 20 mg/kg) increased the protective potential of carbamazepine and nimodipine (20 mg/kg) also decreased the ED50 of diphenylhydantoin against maximum electroshock. However, nicardipine distinctly increased the level of carbamazepine in plasma, whilst nimodipine did not affect the level of both antiepileptics in plasma. The combined treatment of calcium channel inhibitors and antiepileptic drugs, providing a 50% protection against maximum electroshock, did not significantly change the motor performance of mice in the chimney test, when compared with antiepileptic drugs, given alone at their ED50s, against maximum electroshock-induced convulsions. The present results give further support to the idea of the combined use of some calcium channel inhibitors and antiepileptic drugs in the treatment of human epilepsy.

Acute and chronic effects of the synthetic neuroactive steroid, ganaxolone, against the convulsive and lethal effects of pentylenetetrazol in seizure-kindled mice: comparison with diazepam and valproate.

A high-affinity positive modulator of the GABA(A) receptor complex, ganaxolone, is a 3beta-methylated analog of the naturally occurring neuroactive steroid allopregnanolone. In the present study, ganaxolone was tested for its ability to (1) suppress seizures (clonic and tonic) and lethality induced by pentylenetetrazol (PTZ) in PTZ-kindled mice (anticonvulsive effect) and (2) to attenuate the development of sensitization to the convulsive and lethal effects of PTZ in kindled mice (anti-epileptogenic effect) when given as a pretreatment prior to each PTZ injection during kindling acquisition. Two classical antiepileptic drugs, diazepam and valproate, were tested for comparison. All three drugs dose-dependently suppressed tonic seizures and lethality induced by PTZ in kindled mice; only ganaxolone was effective against clonic seizures. Ganaxolone showed anti-epileptogenic properties as it reduced the sensitivity of kindled mice to the convulsive (clonic and tonic seizures) and lethal effects of PTZ. Diazepam showed anti-epileptogenic effects against tonic seizures and lethality, but not clonic seizures; valproate was ineffective in preventing development of any of these effects. Sensitivity to PTZ-induced seizures and lethality was not affected in mice with a history of repeated treatment with ganaxolone, diazepam, or valproate. The drugs had effects on ambulatory activity that ranged from no effect (ganaxolone) through moderate impairment (diazepam) to marked disruption (valproate). Taken together, the results of the present study add to accumulating evidence of the unique anticonvulsive/behavioral profile of neuroactive steroids.

Pharmacological and behavioral characterization of cocaine-kindled seizures in mice.

RATIONALE: Convulsions associated with cocaine toxicity are a serious aspect of cocaine-related emergency room incidents. Seizures can result from a single high dose of cocaine, and evidence is accumulating that correlates repetitive administration of sub-convulsive doses of cocaine with a decreased seizure threshold, a phenomenon known as pharmacological kindling. A murine model of cocaine kindling has not been characterized. OBJECTIVES: To determine the necessary and sufficient conditions for generating increased sensitivity to the convulsive and lethal effects of cocaine and to characterize some of the basic pharmacological and behavioral consequences of this phenomenon in mice. METHODS: Male, Swiss-Webster mice were given repeated injections of cocaine. RESULTS: Daily administration of 60 mg/kg cocaine produced robust kindling; significant leftward shifts in the dose-effect curves for seizures were observed in cocaine-kindled mice. Cocaine kindling was enduring as these left shifts persisted for at least 20 days, indicating possible permanent synaptic changes. Induction of convulsions per se, utilizing 75 mg/kg cocaine, was not sufficient to engender kindling with a non-optimal dose (40 mg/kg). However, administration of a non-kindling dose of cocaine (40 mg/kg) for as few as four occasions produced increased seizure sensitivity to a 60-mg/kg cocaine challenge. The lethal potencies of cocaine and methamphetamine were significantly increased in cocaine-kindled mice. The baseline locomotor activity of kindled mice was not different from that of non-kindled mice. However, challenge doses of cocaine revealed significant differences in the vertically directed activity of kindled versus non-kindled mice. CONCLUSIONS: Overall, this study provides a description of important parameters for a model of cocaine kindling in mice that may be useful for the elucidation of mechanisms responsible for the long-term changes in sensitivity to cocaine and the discovery of novel pharmacological treatments.

Behavioral effects of nicotine, amphetamine and cocaine under a fixed-interval schedule of food reinforcement in rats chronically exposed to caffeine.

Epidemiological surveys demonstrate that caffeine, the main psychoactive ingredient of coffee, is a positive correlate in drug abuse. To characterize the behavioral nature of caffeine interactions with other psychomotor stimulants, we examined the effects of chronic caffeine exposure on the behavioral responses to nicotine, amphetamine, cocaine, the selective D1 agonist SKF-82958 and the selective D2 receptor agonist NPA, in rats responding under a fixed interval (FI) schedule of food reinforcement. Following stabilization of rates and temporal patterns of responding (mathematically expressed as quarter-life values, QL), twenty-one Sprague-Dawley rats responding under a 5-min FI schedule of food reinforcement were divided into two groups; one (twelve rats) maintained on tap water (control) and the other (nine rats) on caffeine (3 mg/ml added to the drinking water). Following the substitution of caffeine solution for tap water, behavior was temporarily disrupted as evidenced by decreases in responding and QL values which reached a maximum after 72 h (rate 60% and QL 30% below baseline levels). Rats developed complete tolerance to these effects of caffeine over 5 days of caffeine exposure. After response rate and QL values stabilized, effects of drugs were evaluated. Nicotine (0.01-1.0 mg/kg; SC), amphetamine (0.1-5.6; IP), and cocaine (1.0-17; IP) each produced biphasic dose-dependent changes in response rate with maximum increases in response rate following intermediate doses and decreases in response rates following higher doses. The increase in rates of responding produced by amphetamine or cocaine (but not nicotine) were greater (P<0.05) in caffeine-drinking than in water-drinking rats. Both SKF-82958 (0.001-0.3 mg/kg; IP) and NPA (0.0001-0.1; IP) produced only dose-dependent decreases in rates of responding. Caffeine-drinking rats were less sensitive to the rate-depressant effects of SKF-82958 (P<0.05) than water-drinking rats. However, similar changes (P>0.05) were produced by NPA in both groups. Except for amphetamine, the remaining drugs produced similar (P>0.05) dose-dependent decreases in QL values in water- and caffeine-drinking rats. Amphetamine produced smaller decreases in QL values in caffeine-drinking rats than in water-drinking rats (P<0.05). Chronic exposure to caffeine produced complete insurmountable tolerance to the response-rate increasing (stimulant) effects of acute caffeine (3.0-17 mg/kg; IP) in caffeine-drinking rats. In conclusion, our study revealed that chronic caffeine exposure potentiates the behavioral response to amphetamine and cocaine but not to that of nicotine in rats responding under a FI schedule of food reinforcement. Thus, it is likely that these effects are mediated through different pharmacological mechanisms.

Modification of behavioral effects of drugs in mice by neuroactive steroids.

RATIONALE: Neuroactive steroids represent a novel class of potential therapeutic agents (epilepsy, anxiety, migraine, drug dependence) thought to act through positive allosteric modulation of the GABA(A) receptor. A synthetically derived neuroactive steroid, ganaxolone (3alphahydroxy-3beta-methyl-5alpha-pregnan-20-one), is in phase-II clinical trials for epilepsy. Unlike traditional anticonvulsants such as diazepam and phenobarbital, ganaxolone shows equipotent suppression of both the seizure activity and the behavioral effects of pentylenetetrazol (PTZ) administration. OBJECTIVES: The present study explored possible reversal by ganaxolone and related neuroactive steroids of some behavioral effects of additional pharmacological challenges. METHODS: Direct behavioral observation and photocell-counted locomotor activity of male, Swiss-Webster mice were made with various compounds alone and in conjunction with ganaxolone. RESULTS: Ganaxolone both prevented and reversed PTZ-induced locomotor depression in mice. Further, ganaxolone reversed the locomotor depression induced by other convulsant/anxiogenic stimuli: bicuculline, picrotoxin and, to a lesser extent, yohimbine. Ganaxolone failed to reverse the locomotor stimulation induced by cocaine, methamphetamine, dizocilpine, and phencyclidine. In addition to ganaxolone, the endogenous neuroactive steroids allopregnanolone and pregnanolone and the synthetic neuroactive steroid Co 2-1068 also reversed observed behaviors and locomotor depression induced by PTZ. CONCLUSIONS: The present findings support the unique pharmacological effects of neuroactive steroids as a novel class of positive allosteric modulators of GABA.