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P.1.c.035 Gabapentin and topiramate protect rat neurons against staurosporine induced apoptosis
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P.1.c Basic neuroscience – Neuropharmacology
P.1.c.034 Pharmacokinetics of licarbazepine in healthy volunteers: single and multiple oral doses and effect of food C. Souppart1 ° , A. Gardin1 , G. Greig2 , S. Balez3 , Y. Batard4 , A. Krebs-Brown5 , S. Appel-Dingemanse1 . 1 Novartis Pharma AG, DMPK, Drug Metabolism and Pharmacokinetics, Basel, Switzerland; 2 Hoffman-La Roche Ltd, Research, Basel, Switzerland; 3 Novartis Pharma S.A.S, DMPK, Drug Metabolism and Pharmacokinetics, Basel, Switzerland; 4 Novartis Pharma AG, Exploratory Clinical Department, Basel, Switzerland; 5 Novartis Pharma AG, Biostatistics and Statistical Reporting, Basel, Switzerland Aim: Licarbazepine is a new chemical entity in development for the treatment of bipolar disorder. It is the synthetic racemate of the pharmacologically active monohydroxy derivative of oxcarbazepine. The development of licarbazepine as an antimanic agent derives from the positive outcome of several studies using the chemically related prodrugs oxcarbazepine and carbamazepine as mood stabilizers. Licarbazepine’s development as a mood stabilizer is intended to provide a new therapeutic option with a favorable safety and tolerability profile aimed at improving patient adherence to treatment. Methods: The combined results from two pharmacokinetic studies provide information on the single- and multiple-dose pharmacokinetics of 500 mg licarbazepine and the effects of food on the single-dose pharmacokinetics of 500 mg licarbazepine given as two 250 mg immediate-release tablets. Both studies followed randomized, crossover, open-label designs and included a 21-day screening period. Each treatment was followed by observation and blood sampling for 48 hours. Subjects were healthy, non-smoking men or women between 18 and 45 years of age. Plasma concentrations of licarbazepine and its two metabolites, oxcarbazepine and the pharmacologically inactive dihydro derivative were determined by liquid chromatography/tandem mass spectrometry with a limit of quantification of 0.1 mmol/L using 50 mL of plasma. Pharmacokinetic parameters were calculated by the standard method for non-compartmental analysis. Results: After single-dose 500 mg licarbazepine administration on day 1, systemic appearance of drug was rapid, with a Tmax of 2 hours. Geometric mean Cmax and AUC0−8 were 30.7 mmol/L and 503 hr·mmol/L, respectively. Inter-subject variability in licarbazepine pharmacokinetic parameters was low (CV~20%). After BID administration of 500 mg licarbazepine on days 3 to 6, followed by a single 500 mg dose on day 7, geometric mean (%CV) ss o were 77.6 mmol/L (18), 45.3 mmol/L (25), Css max , Cmin , and AUCˆ and 747 hr·mmol/L (19), respectively, with a Tmax of 2 hours. The fluctuation index was 51%, and the accumulation ratio was 2.8. The mean apparent half-life was 9.3 and 11.3 hours for singleand multiple-dose licarbazepine administration, respectively. Food ingestion had no clinically significant effect on licarbazepine’s pharmacokinetics. The observed 90% confidence interval for the ratio of geometric means was within the bioequivalence limits of 0.80 to 1.25 for both AUC0−8 (0.92−0.98) and Cmax (0.81−0.94). The t 1 (10.2 hours and 9.9 hours, fasted and fed, respectively) 2
and the inter-subject variability in the main pharmacokinetic parameters were also similar under fasted and fed conditions (CV about 20% for AUC0−8 and 15% for Cmax ). Median Tmax was slightly prolonged under fed conditions (2.5 hours) compared with fasted conditions (1.5 hours). Minor metabolism of licarbazepine to oxcarbazepine and the dihydroxy derivative was observed.
Licarbazepine was safe and well tolerated, with no serious adverse events. Conclusions: Licarbazepine’s predictable pharmacokinetic profile is suitable for BID treatment of bipolar disorder. Licarbazepine’s fluctuation index is low, as is inter-subject variability in pharmacokinetic parameters, overall suggesting an easy dosing. The lack of significant food effect obviates the need for meal restrictions and should enhance adherence to therapy.
P.1.c.035 Gabapentin and topiramate protect rat neurons against staurosporine induced apoptosis S. Abramovici ° , O. Bajenaru, B.O. Popescu. “Carol Davila” University of Medicine and Pharmacy, Neurology dept., Bucharest, Romania Gabapentin (GBP) is increasingly used in clinical neurology for the adjunctive management of chronic refractory pain and partial convulsive seizures. Along with GBP, topiramate (TPM) is also largely used in the treatment of convulsive disorders. GBP and TPM have been shown to have some neuroprotective effect in a limited variety of models. However, data is still insufficient for setting neuroprotection as a new therapeutic indication for these drugs. The aim of our study was to determine whether normal therapeutic plasma levels of GBP and TPM modulate staurosporine (STS) induced neuronal apoptosis. We used rat cerebellar granular cell cultures (CGC), harvested from Wistar rat pups on postnatal day 3−5, in which we induced cellular apoptosis by exposing the cultures to STS (1 mM) for either 6 or 24 hours, with or without co-incubation with TPM (30 mM) or GBP (1, 5 and 20 mg/ml). The CGC were incubated in a humidified atmosphere at 37ºC with 5% CO2 for 96 hours prior to exposure. Neuronal apoptosis was quantified by morphologically determining the percentage of apoptotic neurons using propidium iodide chromatin staining. We further validated our results by cell viability quantification, using the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide (MTT) spectrophotometric assay. All culture experiments were repeated in triplicate and the results are reported as mean±SEM. We analyzed the data using student’s T-test and significance was accepted for p < 0.05. Our results indicate that the percentage of neuronal apoptosis was significantly lower in the lots with TPM and GBP (5 mg/ml) than in the one only with STS (23.34±3.03%, 27.11±3.91% and 43.55±2.92% respectively) after 6 hours of exposure to STS. At 24 hours of exposure to STS there was no significant difference regarding GBP; however the cells protected with TPM showed a lower percentage of apoptosis than those without protection (66.07±4.24% and 87.90±4.07% respectively). We further compared the viability of the cells using MTT in order to validate our morphological results. Viability was significantly higher in the lots protected with TPM and GBP (5 mg/ml) than that exposed only to STS for 6 hours (90.60±3.46%, 91.20±2.23% and 76.47±2.67% respectively, in rapport to control). However, there was no significant protection of either TPM or GBP at 24 hours of exposure to STS. In conclusion, our study shows that both GBP and TPM protect cultured rat cerebellar neurons against STS induced apoptosis after 6 hours of exposure. However, after 24 hours of exposure only TPM seemed to offer some limited protection in the morphologic study. The data regarding TPM protection at 24 hours of exposure to STS was not backed by the results obtained using MTT. Because
P.1.c Basic neuroscience – Neuropharmacology of that discordance between the data regarding TPM protection at 24 hours of exposure to STS we decided to repeat some of the experiments. Furthermore, we are now trying to elucidate the biochemical mechanism by which TPM and GBP protect CGC against STS induced apoptosis. P.1.c.036 Seizure-induced hypothermia in biotelemetered rats E.S. Akarsu ° , S. Mamuk. Ankara University, School of Medicine, Dept. Pharmacology and Clin. Pharmacology, Ankara, Turkey Background: Experimental evidence suggests that hypothermia may develop as a thermoregulatory response during the course of systemic inflammation due to immunological challenge (e.g. lipopolysaccharide treatment) in rats. An elevation of the serum levels of putative endogenous cryogenic cytokines such as tumor necrosis factor (TNF)-a or interleukin (IL)-10 has been associated with the hypothermia (Dogan et al., 2002). It has also been reported that the innate immune reaction is activated in response to seizures (Turrin and Rivest, 2004). Thus, in this study we evaluated the body temperature (Tb) changes, latency and intensity of seizures and related serum TNF-a and IL-10 alterations after picrotoxin (a chemical convulsant) administration in rats. Material and Methods: The Tb of the male albino rats (240–270 g) was monitored by a telemetric system (Mini-Mitter, Oregon, USA). Telemetric transmitters were implanted into the peritoneal cavity of the rats under general anaesthesia (ketamine + xylasine, 80+10 mg/kg, ip; respectively) at least 7 days before the experiments. The Tb was recorded at 10 sec intervals for 5 h. The changes in Tb were expressed as a difference from the baseline value for each rat (dT). The animals were observed directly for the latency and the duration of the tonic-clonic seizures after picrotoxin injection alone (2.5 mg/kg, ip) or together with carbamazepine pretreatment (20 mg/kg, sc, 20 min before picrotoxin challenge). On the other group of rats, blood samples were taken by intracardiac puncture under light ether anaesthesia for TNF-a and IL-10 quantitation by enzyme-linked immunosorbent assay (ELISA). Rat specific ELISA kits were purchased from Biosource (Camarillo, CA, USA). The detection limit of the assay was 4 pg/ml for each cytokine. Parametric or nonparametric analysis of variance with appropriate post-hoc tests was used as the statistical methods. The local ethical committee of Ankara University, School of Medicine has approved all experimental protocols. Results: Picrotoxin produced tonic-clonic seizures that started about 420 sec after injection and lasted approximately for 400 sec. The Tb begun to decrease simultaneously with the initiation of generalized tonic seizures. The decrease of Tb accelerated by the end of the convulsive attacks and the response reached its nadir (dTb: −2.9±0.11ºC) at about 50 min after picrotoxin injection. The animal remained hypothermic for about 4 h. Carbamazepine pretreatment preferentially abolished the generalized clonic seizures and partially attenuated the hypothermia. Serum TNF-a and IL-10 levels did not change either at the initial period of seizures with a mean dTb: −1ºC or after the seizures with a nadir dTb about −3ºC. Conclusion: The data show that picrotoxin-induced convulsive seizures cause a profound and long-lasting hypothermic response in rats. This response may be an adaptive strategy for reducing of the increased neuronal activity. Meanwhile, peripheral endogenous cryogenic cytokine activation may not be accounted for as a possible mechanism of action for the seizure-induce hypothermia.
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References [1] Dogan MD, Ataoglu H, Akarsu ES, 2002, Characterization of the hypothermic component of LPS-induced dual thermoregulatory response in rats, Pharmacol. Biochem. Behav., 72, 143–150. [2] Turrin NP, Rivest S, 2004, Innate immune reaction in response to seizures: implication for the neuropathology associated with epilepsy, Neurobiol. Dis., 16, 312–334.
P.1.c.037 Mitochondria as the memantine target E.P. Shevtsova ° , L.G. Dubova, E.G. Kireeva, S.O. Bachurin. Institute of Physiologicaly Active Compounds RAS, Lab. Neurochemistry, Chernogolovka, Russian Federation The mitochondrial permeability transition (mPT) event is implicated in the different scenarios of the cell death, and is therefore postulated to play a key role in age-dependent degenerative diseases, in particular, in number of neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease. We have shown earlier that some model neurotoxins, simulating neurodegenerative disease can induce or potentate the mPT. From the other hand it was revealed that the neuroprotective action of some widely used and prospective medicines might be also, at least in part, the result of its interaction with mitochondria. Among such drugs there are the tacrin, dimebon, endogenous neuroprotector N-acethylserotonin (NAS) and extract of Gingko biloba. These agents can increase the resistance of neurons to cell death by attenuating the mPT. Memantine is a low-affinity, uncompetitive open-channel blocker of the NMDA receptor and has excellent safety and efficacy profiles for treatment of Alzheimer’s disease. Intriguingly, but recently it was shown that memantine interacts with its specific-blocking site in the same fashion as intracellular rather than extracellular Mg2+. On the other hand, NMDA receptor already intimately connected with the mitochondria and undoubtedly its functioning dependent on mitochondria ability to cycling calcium. So the aim of our study is the investigation of memantine interaction with mitochondria. Experiments were performed on isolated mitochondria from rat brain and liver. Rat liver mitochondria we prepare via the standard mannitol differential centrifugation protocol and resuspended in sufficient buffer A (0.21M mannitol, 70 mM sucrose, 5 mM Hepes, pH 7.4, at 4ºC). Brain mitochondria isolated accoding Sims using Percoll gradient method in buffer with 0.3M sucrose, 1 mM K2EDTA, 10 mM Hepes, pH 7.4, at 4ºC. Changes in the status of the mPT pore are. Mitochondria functioning was evaluated according the standard methods: induction of mPT estimated as swelling of mitochondria and assessed spectrophotometrically at 540 nm.; depolarization of mitochondria and calcium retention capacity measured fluorometrically with the safranin and arsenaso III, accordingly, the peroxidation of mitochondrial lipids MDA was assayed as a thiobarbituric acid reactive substance and respiratory activity of mitochondria was investigated using the Clarktype electrode (OROBOROS oxygraph). We have shown that memantine in micromolar concentrations significantly decrease the vulnerability of mitochondria to mPT induction with different inductors. But this effect is not connected with the inhibition of calcium entry into mitochondria, moreover, memantine increase the calcium retention capacity of mitochondria. We didn’t reveal any memantine-induced changes in the activity of mitochondrial respiratory chain and memantine influence on lipid peroxidation in mitochondria. Our results allow us to conclude that the neuroprotective effect of memantine may be the result of it’s complex interaction not only with the calcium channel of NMDA receptor
P.1.c Basic neuroscience – Neuropharmacology
P.1.c.034 Pharmacokinetics of licarbazepine in healthy volunteers: single and multiple oral doses and effect of food C. Souppart1 ° , A. Gardin1 , G. Greig2 , S. Balez3 , Y. Batard4 , A. Krebs-Brown5 , S. Appel-Dingemanse1 . 1 Novartis Pharma AG, DMPK, Drug Metabolism and Pharmacokinetics, Basel, Switzerland; 2 Hoffman-La Roche Ltd, Research, Basel, Switzerland; 3 Novartis Pharma S.A.S, DMPK, Drug Metabolism and Pharmacokinetics, Basel, Switzerland; 4 Novartis Pharma AG, Exploratory Clinical Department, Basel, Switzerland; 5 Novartis Pharma AG, Biostatistics and Statistical Reporting, Basel, Switzerland Aim: Licarbazepine is a new chemical entity in development for the treatment of bipolar disorder. It is the synthetic racemate of the pharmacologically active monohydroxy derivative of oxcarbazepine. The development of licarbazepine as an antimanic agent derives from the positive outcome of several studies using the chemically related prodrugs oxcarbazepine and carbamazepine as mood stabilizers. Licarbazepine’s development as a mood stabilizer is intended to provide a new therapeutic option with a favorable safety and tolerability profile aimed at improving patient adherence to treatment. Methods: The combined results from two pharmacokinetic studies provide information on the single- and multiple-dose pharmacokinetics of 500 mg licarbazepine and the effects of food on the single-dose pharmacokinetics of 500 mg licarbazepine given as two 250 mg immediate-release tablets. Both studies followed randomized, crossover, open-label designs and included a 21-day screening period. Each treatment was followed by observation and blood sampling for 48 hours. Subjects were healthy, non-smoking men or women between 18 and 45 years of age. Plasma concentrations of licarbazepine and its two metabolites, oxcarbazepine and the pharmacologically inactive dihydro derivative were determined by liquid chromatography/tandem mass spectrometry with a limit of quantification of 0.1 mmol/L using 50 mL of plasma. Pharmacokinetic parameters were calculated by the standard method for non-compartmental analysis. Results: After single-dose 500 mg licarbazepine administration on day 1, systemic appearance of drug was rapid, with a Tmax of 2 hours. Geometric mean Cmax and AUC0−8 were 30.7 mmol/L and 503 hr·mmol/L, respectively. Inter-subject variability in licarbazepine pharmacokinetic parameters was low (CV~20%). After BID administration of 500 mg licarbazepine on days 3 to 6, followed by a single 500 mg dose on day 7, geometric mean (%CV) ss o were 77.6 mmol/L (18), 45.3 mmol/L (25), Css max , Cmin , and AUCˆ and 747 hr·mmol/L (19), respectively, with a Tmax of 2 hours. The fluctuation index was 51%, and the accumulation ratio was 2.8. The mean apparent half-life was 9.3 and 11.3 hours for singleand multiple-dose licarbazepine administration, respectively. Food ingestion had no clinically significant effect on licarbazepine’s pharmacokinetics. The observed 90% confidence interval for the ratio of geometric means was within the bioequivalence limits of 0.80 to 1.25 for both AUC0−8 (0.92−0.98) and Cmax (0.81−0.94). The t 1 (10.2 hours and 9.9 hours, fasted and fed, respectively) 2
and the inter-subject variability in the main pharmacokinetic parameters were also similar under fasted and fed conditions (CV about 20% for AUC0−8 and 15% for Cmax ). Median Tmax was slightly prolonged under fed conditions (2.5 hours) compared with fasted conditions (1.5 hours). Minor metabolism of licarbazepine to oxcarbazepine and the dihydroxy derivative was observed.
Licarbazepine was safe and well tolerated, with no serious adverse events. Conclusions: Licarbazepine’s predictable pharmacokinetic profile is suitable for BID treatment of bipolar disorder. Licarbazepine’s fluctuation index is low, as is inter-subject variability in pharmacokinetic parameters, overall suggesting an easy dosing. The lack of significant food effect obviates the need for meal restrictions and should enhance adherence to therapy.
P.1.c.035 Gabapentin and topiramate protect rat neurons against staurosporine induced apoptosis S. Abramovici ° , O. Bajenaru, B.O. Popescu. “Carol Davila” University of Medicine and Pharmacy, Neurology dept., Bucharest, Romania Gabapentin (GBP) is increasingly used in clinical neurology for the adjunctive management of chronic refractory pain and partial convulsive seizures. Along with GBP, topiramate (TPM) is also largely used in the treatment of convulsive disorders. GBP and TPM have been shown to have some neuroprotective effect in a limited variety of models. However, data is still insufficient for setting neuroprotection as a new therapeutic indication for these drugs. The aim of our study was to determine whether normal therapeutic plasma levels of GBP and TPM modulate staurosporine (STS) induced neuronal apoptosis. We used rat cerebellar granular cell cultures (CGC), harvested from Wistar rat pups on postnatal day 3−5, in which we induced cellular apoptosis by exposing the cultures to STS (1 mM) for either 6 or 24 hours, with or without co-incubation with TPM (30 mM) or GBP (1, 5 and 20 mg/ml). The CGC were incubated in a humidified atmosphere at 37ºC with 5% CO2 for 96 hours prior to exposure. Neuronal apoptosis was quantified by morphologically determining the percentage of apoptotic neurons using propidium iodide chromatin staining. We further validated our results by cell viability quantification, using the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide (MTT) spectrophotometric assay. All culture experiments were repeated in triplicate and the results are reported as mean±SEM. We analyzed the data using student’s T-test and significance was accepted for p < 0.05. Our results indicate that the percentage of neuronal apoptosis was significantly lower in the lots with TPM and GBP (5 mg/ml) than in the one only with STS (23.34±3.03%, 27.11±3.91% and 43.55±2.92% respectively) after 6 hours of exposure to STS. At 24 hours of exposure to STS there was no significant difference regarding GBP; however the cells protected with TPM showed a lower percentage of apoptosis than those without protection (66.07±4.24% and 87.90±4.07% respectively). We further compared the viability of the cells using MTT in order to validate our morphological results. Viability was significantly higher in the lots protected with TPM and GBP (5 mg/ml) than that exposed only to STS for 6 hours (90.60±3.46%, 91.20±2.23% and 76.47±2.67% respectively, in rapport to control). However, there was no significant protection of either TPM or GBP at 24 hours of exposure to STS. In conclusion, our study shows that both GBP and TPM protect cultured rat cerebellar neurons against STS induced apoptosis after 6 hours of exposure. However, after 24 hours of exposure only TPM seemed to offer some limited protection in the morphologic study. The data regarding TPM protection at 24 hours of exposure to STS was not backed by the results obtained using MTT. Because
P.1.c Basic neuroscience – Neuropharmacology of that discordance between the data regarding TPM protection at 24 hours of exposure to STS we decided to repeat some of the experiments. Furthermore, we are now trying to elucidate the biochemical mechanism by which TPM and GBP protect CGC against STS induced apoptosis. P.1.c.036 Seizure-induced hypothermia in biotelemetered rats E.S. Akarsu ° , S. Mamuk. Ankara University, School of Medicine, Dept. Pharmacology and Clin. Pharmacology, Ankara, Turkey Background: Experimental evidence suggests that hypothermia may develop as a thermoregulatory response during the course of systemic inflammation due to immunological challenge (e.g. lipopolysaccharide treatment) in rats. An elevation of the serum levels of putative endogenous cryogenic cytokines such as tumor necrosis factor (TNF)-a or interleukin (IL)-10 has been associated with the hypothermia (Dogan et al., 2002). It has also been reported that the innate immune reaction is activated in response to seizures (Turrin and Rivest, 2004). Thus, in this study we evaluated the body temperature (Tb) changes, latency and intensity of seizures and related serum TNF-a and IL-10 alterations after picrotoxin (a chemical convulsant) administration in rats. Material and Methods: The Tb of the male albino rats (240–270 g) was monitored by a telemetric system (Mini-Mitter, Oregon, USA). Telemetric transmitters were implanted into the peritoneal cavity of the rats under general anaesthesia (ketamine + xylasine, 80+10 mg/kg, ip; respectively) at least 7 days before the experiments. The Tb was recorded at 10 sec intervals for 5 h. The changes in Tb were expressed as a difference from the baseline value for each rat (dT). The animals were observed directly for the latency and the duration of the tonic-clonic seizures after picrotoxin injection alone (2.5 mg/kg, ip) or together with carbamazepine pretreatment (20 mg/kg, sc, 20 min before picrotoxin challenge). On the other group of rats, blood samples were taken by intracardiac puncture under light ether anaesthesia for TNF-a and IL-10 quantitation by enzyme-linked immunosorbent assay (ELISA). Rat specific ELISA kits were purchased from Biosource (Camarillo, CA, USA). The detection limit of the assay was 4 pg/ml for each cytokine. Parametric or nonparametric analysis of variance with appropriate post-hoc tests was used as the statistical methods. The local ethical committee of Ankara University, School of Medicine has approved all experimental protocols. Results: Picrotoxin produced tonic-clonic seizures that started about 420 sec after injection and lasted approximately for 400 sec. The Tb begun to decrease simultaneously with the initiation of generalized tonic seizures. The decrease of Tb accelerated by the end of the convulsive attacks and the response reached its nadir (dTb: −2.9±0.11ºC) at about 50 min after picrotoxin injection. The animal remained hypothermic for about 4 h. Carbamazepine pretreatment preferentially abolished the generalized clonic seizures and partially attenuated the hypothermia. Serum TNF-a and IL-10 levels did not change either at the initial period of seizures with a mean dTb: −1ºC or after the seizures with a nadir dTb about −3ºC. Conclusion: The data show that picrotoxin-induced convulsive seizures cause a profound and long-lasting hypothermic response in rats. This response may be an adaptive strategy for reducing of the increased neuronal activity. Meanwhile, peripheral endogenous cryogenic cytokine activation may not be accounted for as a possible mechanism of action for the seizure-induce hypothermia.
S243
References [1] Dogan MD, Ataoglu H, Akarsu ES, 2002, Characterization of the hypothermic component of LPS-induced dual thermoregulatory response in rats, Pharmacol. Biochem. Behav., 72, 143–150. [2] Turrin NP, Rivest S, 2004, Innate immune reaction in response to seizures: implication for the neuropathology associated with epilepsy, Neurobiol. Dis., 16, 312–334.
P.1.c.037 Mitochondria as the memantine target E.P. Shevtsova ° , L.G. Dubova, E.G. Kireeva, S.O. Bachurin. Institute of Physiologicaly Active Compounds RAS, Lab. Neurochemistry, Chernogolovka, Russian Federation The mitochondrial permeability transition (mPT) event is implicated in the different scenarios of the cell death, and is therefore postulated to play a key role in age-dependent degenerative diseases, in particular, in number of neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease. We have shown earlier that some model neurotoxins, simulating neurodegenerative disease can induce or potentate the mPT. From the other hand it was revealed that the neuroprotective action of some widely used and prospective medicines might be also, at least in part, the result of its interaction with mitochondria. Among such drugs there are the tacrin, dimebon, endogenous neuroprotector N-acethylserotonin (NAS) and extract of Gingko biloba. These agents can increase the resistance of neurons to cell death by attenuating the mPT. Memantine is a low-affinity, uncompetitive open-channel blocker of the NMDA receptor and has excellent safety and efficacy profiles for treatment of Alzheimer’s disease. Intriguingly, but recently it was shown that memantine interacts with its specific-blocking site in the same fashion as intracellular rather than extracellular Mg2+. On the other hand, NMDA receptor already intimately connected with the mitochondria and undoubtedly its functioning dependent on mitochondria ability to cycling calcium. So the aim of our study is the investigation of memantine interaction with mitochondria. Experiments were performed on isolated mitochondria from rat brain and liver. Rat liver mitochondria we prepare via the standard mannitol differential centrifugation protocol and resuspended in sufficient buffer A (0.21M mannitol, 70 mM sucrose, 5 mM Hepes, pH 7.4, at 4ºC). Brain mitochondria isolated accoding Sims using Percoll gradient method in buffer with 0.3M sucrose, 1 mM K2EDTA, 10 mM Hepes, pH 7.4, at 4ºC. Changes in the status of the mPT pore are. Mitochondria functioning was evaluated according the standard methods: induction of mPT estimated as swelling of mitochondria and assessed spectrophotometrically at 540 nm.; depolarization of mitochondria and calcium retention capacity measured fluorometrically with the safranin and arsenaso III, accordingly, the peroxidation of mitochondrial lipids MDA was assayed as a thiobarbituric acid reactive substance and respiratory activity of mitochondria was investigated using the Clarktype electrode (OROBOROS oxygraph). We have shown that memantine in micromolar concentrations significantly decrease the vulnerability of mitochondria to mPT induction with different inductors. But this effect is not connected with the inhibition of calcium entry into mitochondria, moreover, memantine increase the calcium retention capacity of mitochondria. We didn’t reveal any memantine-induced changes in the activity of mitochondrial respiratory chain and memantine influence on lipid peroxidation in mitochondria. Our results allow us to conclude that the neuroprotective effect of memantine may be the result of it’s complex interaction not only with the calcium channel of NMDA receptor