Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Memantine”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed2004

Identification of genes regulated by memantine and MK-801 in adult rat brain by cDNA microarray analysis.

In this study, we monitored gene expression profiles using cDNA microarrays after an acute systemic administration of the high affinity N-methyl-D-aspartate (NMDA) uncompetitive antagonist MK-801 (1 mg/kg; 4 h), and the clinically used moderate affinity antagonist memantine (25 mg/kg; 4 h) in adult rat brains. From a microarray containing 1090 known genes, 13 genes were regulated by both treatments of which 12 were upregulated and one was downregulated. In addition, 28 and 34 genes were regulated (> or = 1.5- or < or = 0.67-fold change) by either memantine or MK-801, respectively. Genes commonly regulated by both treatments and not previously reported were confirmed by in situ hybridization (ISH) and include regenerating liver inhibitory factor-1 (RL/IF-1), GDP-dissociation inhibitor 1 (GDI-1), neural visinin Ca2+-binding protein 2 (NVP-2), neuromedin B receptor, and Na+/K+ transporting ATPase 2beta. ISH with memantine (5-50 mg/kg) revealed regulation of these genes in other cortical and hippocampal regions. RL/IF-1 induction occurred at 1 h and returned to basal levels by 8 h, consistent with the profile of an immediate early gene. Western blot analysis showed increases (approximately 30-65%) in GDI-1 protein present in both cytosolic and membrane fractions that were significant in the 84-kDa Rab bound form, suggesting that memantine influences Ras-like GTPase function. Genes regulated by a 5 mg/kg dose of memantine might be important in its therapeutic effects. These findings increase the number of known, differentially altered genes after treatment of uncompetitive NMDA receptor antagonists and suggest broader actions of these agents than previously realized.

Analysis of Variance↗
PubMed2002

[Use of memantine in progressive glaucoma. Case report].

BACKGROUND: Several animal models demonstrated that NMDA-receptor antagonists like memantine inhibit the excitotoxic action of glutamate in glaucoma. Furthermore, this also enables to slow down the degeneration of retinal ganglion cells. In the following case report we investigated the use and tolerability of memantine in a glaucoma patient. PATIENT AND METHODS: We report on a 73-year old male with progressive glaucoma damage. Treatment with memantine à 20 mg/d lasted for 6 months and was preceded by one week à 10 mg/d. Follow-ups with perimetry and VEP were performed at beginning and 2, 4, 6 and 12 months after. RESULTS: The first control showed an improvement of perimetry. The following examinations demonstrated a stabilization of perimetry and VEP. Because of side-effects there was no tolerability of a higher dose of memantine à 30 mg/d or continuation of the therapy after 6 months. CONCLUSION: Memantine seems to be neuroprotective in glaucoma patients. At present a multicentric study is under way. More results may be expected shortly.

Aged↗
PubMed2000

Memantine (a N-methyl-D-aspartate receptor antagonist) in the treatment of neuropathic pain after amputation or surgery: a randomized, double-blinded, cross-over study.

UNLABELLED: Evidence has accumulated that the N:-methyl-D-aspartate receptor system plays a role in continuous and particularly, in stimulus-evoked pain after nerve injury. We examined, in a randomized, double-blinded, cross-over fashion, the analgesic effect of memantine (a N:-methyl-D-aspartate receptor antagonist) in a group of patients with chronic pain after surgery. We randomized 19 patients to receive either memantine or placebo in the first 5-wk treatment period. A washout period of 4 wks was followed by another 5-wk treatment period with the opposite drug. The dosage of drug was increased from 5 to 20 mg/d. Pain was recorded daily, with the use of a 0-10 numeric rating scale. Before and at the end of each treatment period, pain and sensitivity were also assessed by using the McGill Pain Questionnaire, allodynia to touch, brush and cold, wind-up-like pain, and thresholds to mechanical stimuli (pressure and von Frey hair). A total of 15 patients (12 amputees and three patients with other nerve injuries) completed the study. There was no difference between memantine and placebo on any of the outcome measures. We conclude that memantine at a dosage of 20 mg/d does not reduce spontaneous or evoked pain in patients with nerve injury pain. IMPLICATIONS: In a randomized, double-blinded and cross-over study, the analgesic effect of memantine (a drug which reduces the excitability of sensitized neurons in the dorsal horn) was examined in 19 patients with chronic pain after nerve injury.

Adult↗
PubMed2002

Dextromethorphan and memantine in painful diabetic neuropathy and postherpetic neuralgia: efficacy and dose-response trials.

BACKGROUND: There are few repeated dose-controlled trials of N-methyl-d-aspartate glutamate receptor antagonists in patients with neuropathic pain. The authors sought to evaluate two low-affinity N-methyl-d-aspartate antagonists using a novel two-stage design. METHODS: The authors studied patients with painful diabetic neuropathy (DN) and postherpetic neuralgia (PHN) in two crossover trials: (1) efficacy trial (dextromethorphan vs. memantine vs. active placebo [lorazepam]) and (2) dose-response trial of the preferred active drug in responders from the first study (0% vs. 25% vs. 50% vs. 100% of each patient's maximally tolerated dose). Pain intensity was measured on a 20-point scale. RESULTS: Nineteen of 23 DN patients and 17 of 21 PHN patients completed the efficacy trial. Median doses for DN and PHN were 400 and 400 mg/day dextromethorphan, 55 and 35 mg/day memantine, and 1.8 and 1.2 mg/day lorazepam. In the efficacy trial, among patients with DN, dextromethorphan reduced pain intensity by a mean of 33% from baseline, memantine reduced pain intensity by a mean of 17%, and lorazepam reduced pain intensity by a mean of 16%; the proportions of subjects achieving greater than moderate pain relief were 68% with dextromethorphan, 47% with memantine, and 37% with lorazepam. Mean reductions in pain intensity in patients with PHN were 6% with dextromethorphan, 2% with memantine, and 0% with lorazepam. No comparison with placebo reached statistical significance in the efficacy trial. In the 10 DN subjects who responded to dextromethorphan, there was a significant dose-response effect on pain intensity (P = 0.035), with the highest dose significantly better than that of lorazepam (P = 0.03). CONCLUSIONS: Dextromethorphan is effective in a dose-related fashion in selected patients with DN. This was not true of PHN, suggesting a difference in pain mechanisms. Selective approaches to pain-relevant N-methyl-d-aspartate receptors are warranted.

Adult↗
PubMed2006

Memantine treatment in mild to moderate Alzheimer disease: a 24-week randomized, controlled trial.

OBJECTIVE: The objective of this study was to compare the efficacy and safety of the moderate-affinity, uncompetitive N-methyl-d-aspartate receptor antagonist, memantine, versus placebo in patients with mild to moderate Alzheimer disease (AD). METHOD: This was a randomized, double-blind, placebo-controlled clinical trial conducted at 42 U.S. sites. Participants were 403 outpatients with mild to moderate AD and Mini-Mental State Examination scores of 10-22 randomized to memantine (20 mg/day; N=201) or placebo (N=202) for 24 weeks. Primary outcomes were change from baseline at 24 weeks on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog), a measure of cognition, and on the Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus), a global measure. Secondary outcomes included change on the Neuropsychiatric Inventory (NPI) and the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory (ADCS-ADL(23)), measures of behavior and function, respectively. RESULTS: Most (82.4%) participants completed the trial. Memantine resulted in significantly better outcomes than placebo on measures of cognition, global status, and behavior when based on the protocol-specified primary last observation carried forward imputation as well as a mixed-models repeated-measures approach applied to the continuous outcomes. Treatment discontinuations because of adverse events for memantine versus placebo were 19 (9.5%) and 10 (5.0%), respectively. CONCLUSIONS: These results support the safety and efficacy of memantine for the treatment of mild to moderate AD.

Aged↗
PubMedDate not supplied

Efficacy and safety of memantine in moderate-to-severe Alzheimer disease: the evidence to date.

Memantine, a moderate-affinity, uncompetitive N-methyl-D-aspartate receptor antagonist, is currently the only agent approved for moderately severe to severe Alzheimer disease (AD) in Europe and for moderate-to-severe Alzheimer disease in the United States. In clinical trials, memantine has consistently demonstrated a reduced rate of deterioration on global, cognitive, functional, and behavioral measures, across a range of outcome measures compared with usual care. Notably, improvements versus placebo were seen in individual activities of daily living and behavior, particularly agitation. Efficacy was demonstrated in patients with newly diagnosed Alzheimer disease, patients previously or currently receiving acetylcholinesterase inhibitors, and both institutionalized and community-dwelling Alzheimer disease patients. Memantine has a tolerability profile similar to placebo. This review presents the results of key clinical trials, and includes clinically relevant analyses, such as numbers-needed-to-treat and effect sizes. Increased dependency and institutionalization are significant cost drivers in Alzheimer disease. Memantine is able to reduce dependency, caregiver time required, and mean monthly caregiver and societal costs. Recent studies of the relationship between Alzheimer disease progression, caregiver burden, and healthcare costs emphasize the need for treatments such as memantine that can slow the rate of decline in Alzheimer disease.

Activities of Daily Living↗
PubMed1993

Potential antidepressive properties of amantadine, memantine and bifemelane.

The effects of amantadine, its dimethyl derivative, memantine and the chemically unrelated compound bifemelane were tested for antidepressant activity. Reserpine-induced hypothermia and the forced swim test (Porsolt test) were selected for this purpose. In the former test amantadine and bifemelane but not memantine were effective. In the forced swim test all three agents produced antidepressive-like activity (decreased immobility time), but in case of bifemelane it was less pronounced. The effect in the forced swim test was specific i.e. it was apparently not the result of an increase in general activity as evidenced by control experiments in the open field. The mechanism of amantadine and memantine action may involve indirect dopaminomimetic activity resulting from the blockade of NMDA receptors. However in reserpine-induced hypothermia this explanation is not valid considering the lack of effect of memantine and positive action of amantadine. Hence, amantadine may have an additional central sympathomimetic action that memantine is lacking. Bifemelane antidepressant-like activity might be attributed to an enhancement of noradrenergic transmission. We suggested that amantadine and bifemelane could be particularly useful therapeutically when depressive symptoms are present in patients suffering from Parkinson's disease and dementia.

Amantadine↗
PubMed1988

Interaction of memantine with cholecystokinin receptors in mouse brain.

The effect of memantine on CCK receptors in mouse brain has been investigated using particles of dissected cortex and striatum. Total binding of radio-labelled CCK33 was one-half maximal within 10 min of incubation and reached a maximum after 30 to 60 min when either cortex or striatum was used. Non-specific binding (presence of 100 microM unlabelled CCK8) was 50 to 80% of total binding at steady state conditions. CCK8 inhibited specific binding of radiolabelled CCK33 in a dose-dependent manner; the IC50 (half-maximal inhibitory concentration) was in the range 3 to 4 nM. Memantine increased CCK binding in a concentration-dependent manner, though at high concentrations. The EC50 (half-maximal effective concentration) of this effect was less than 100 microM. The memantine effect is not due to an inhibition of labelled CCK degradation in the medium. The effect of memantine on CCK binding is unique for brain since it was not observed in pancreatic acinar membranes. These data, therefore, suggest a modulatory effect of memantine on CCK receptors in mouse brain (cortex and striatum) particles.

Amantadine↗
PubMed2004

Efficacy and safety of memantine treatment for reduction of changes associated with experimental glaucoma in monkey, I: Functional measures.

PURPOSE: To determine, using electrophysiological measures of visual system function, whether oral daily dosing of memantine is both safe and effective to reduce the injury associated with experimental glaucoma in primates. METHODS: Argon laser treatment of the anterior chamber angle was used to induce chronic ocular hypertension (COHT) in the right eye of 18 macaque monkeys. Nine animals were orally dosed daily with 4 mg/kg memantine while the other nine animals received an oral dose of vehicle only. Using both conventional and multifocal methods, recordings of the electroretinogram (ERG) were made at approximately 3, 5, and 16 months after elevation of the intraocular pressure (IOP). Recordings of the visually-evoked cortical potential (VECP) were also made at the 16-month time point. RESULTS: Chronic ocular hypertension was associated with a reduction in the amplitude of components of the multifocal ERG response and visually-evoked cortical potential. Memantine-treated animals suffered less amplitude reduction for these measures than did vehicle-treated animals, though this treatment effect on the ERG measures was observed only at the early time points (3 and 5 months post IOP elevation). Memantine treatment was not associated with an effect on either the kinetics or amplitude of ERG or VECP response measures obtained from the normotensive eyes. CONCLUSIONS: Systemic treatment with memantine, a compound which does not lower intraocular pressure, was both safe and effective for reduction of functional loss associated with experimental glaucoma.

Administration, Oral↗
PubMedDate not supplied

Memantine: targeting glutamate excitotoxicity in Alzheimer's disease and other dementias.

The management of dementia has changed since the development of new antidementia drugs. The benefits observed in Alzheimer's disease (AD) with selective cholinergic transmission treatments are mainly symptomatic, without clear evidence of neuroprotection. The hypothesis that glutamate-mediated neurotoxicity is involved in the pathogenesis of AD is finding increasingly more acceptance in the scientific community. Glutamate receptors are overactive, and N-methyl-D-aspartate (NMDA) receptor antagonists have therapeutic potential for the treatment of AD and other neurological disorders. Memantine is a noncompetitive NMDA antagonist that is considered a neuroprotective drug. Memantine's capacity has been demonstrated in preclinical studies, and it is considered a useful symptomatic treatment for AD. Memantine has been shown to benefit cognition, function, and global outcome in patients with moderate to severe AD, and it is currently approved by the US Food and Drug Administration (FDA) for the treatment of moderate to severe AD. Recently, memantine has also demonstrated efficacy in the initial stages of AD, although FDA authorization is pending. This review highlights the important pharmacological and clinical aspects of memantine, as well as some basic mechanisms mediating glutamatergic neurodegeneration.

Amino Acid Transport System X-AG↗
PubMed2005

Antipsychotic dose-sparing effect with addition of memantine.

OBJECTIVE: To describe a case of an antipsychotic-sparing effect achieved after the addition of memantine to the regimen of a patient with severe Alzheimer's disease and aggressive behavioral disturbances. CASE SUMMARY: A 78-year-old white man with severe Alzheimer's disease was receiving risperidone 2 mg 3 times daily for persistent aggressive and dangerous behavioral disturbances. Memantine was initiated, and the dose was titrated to 10 mg twice daily. The patient's response included improvement in functional status and resolution of problematic behaviors, allowing repeated reduction of the risperidone dose and ultimate discontinuation. DISCUSSION: Antipsychotics are often employed to treat behavioral disturbances for patients with Alzheimer's disease; however, the adverse effect potential of these agents remains a significant concern. Adjunctive medications that maintain or improve behavioral symptoms yet allow an antipsychotic-sparing effect are attractive. Such experiences have previously been described with other drug classes, but clinical experience is evolving with memantine. For this patient, the effect of this agent on behavioral symptoms and risperidone requirements is one example of such an antipsychotic-sparing effect. CONCLUSIONS: Response to memantine therapy may include behavioral improvements allowing a dose-sparing effect of antipsychotic medication. Changes in psychoactive drug burden may be a valuable surrogate marker of memantine's effects on behavior.

Aged↗
PubMed2006

Memantine: a review of its use in Alzheimer's disease.

Memantine (Ebixa, Axura, Namenda, Akatinol) is a moderate-affinity, uncompetitive, voltage-dependent, NMDA-receptor antagonist with fast on/off kinetics that inhibits excessive calcium influx induced by chronic overstimulation of the NMDA receptor. Memantine is approved in the US and the EU for the treatment of patients with moderate to severe dementia of the Alzheimer's type. In well designed clinical trials, oral memantine, as monotherapy or in addition to a stable dose of acetylcholinesterase inhibitors, was well tolerated during the treatment of mild to severe Alzheimer's disease for up to 52 weeks. Memantine generally modified the progressive symptomatic decline in global status, cognition, function and behaviour exhibited by patients with moderate to severe Alzheimer's disease in four 12- to 28-week trials. In patients with mild to moderate Alzheimer's disease, data from three 24-week trials are equivocal, although meta-analyses indicate beneficial effects on global status and cognition. Memantine is an effective pharmacotherapeutic agent, and currently the only approved option, for the treatment of moderate to severe Alzheimer's disease.

Alzheimer Disease↗
PubMed2004

NMDA-antagonism (memantine): an alternative pharmacological therapeutic principle in Alzheimer's and vascular dementia.

Memantine, a non-competitive NMDA antagonist, has been clinically used in the treatment of dementia in Germany for over ten years. The rationale for this indication is strongly related to the physiological and to the pathological role of glutamate in neurotransmission. Physiologically, NMDA receptors mediate synaptic plasticity by acting as a coincidence detector. Only those synapses that show temporally and spatially discrete activation of NMDA receptors undergo plastic changes secondary to Ca++ influx after rapid unblocking of Mg++, thus crucially contributing to memory and learning processes. The voltage-dependency of Mg++ is so pronounced that under pathological conditions it leaves the NMDA channel upon moderate depolarisation, thus interrupting memory and learning. Its pharmacological properties allow memantine to rapidly leave the NMDA channel upon transient physiological activation by synaptic glutamate (restoring significant signal transmission), but to block the sustained activation of low glutamate concentration under pathological conditions, i.e. to protect against excitotoxicity as a pathomechanism of neurodegenerative disorders. Memantine acts as a neuroprotective agent in various animal models based on both neurodegenerative and vascular processes as it ameliorates cognitive and memory deficits. Memantine has shown to be effective and safe in the treatment of dementia, particularly Alzheimer's disease, in controlled clinical trials. Provided that the dose is slowly increased it is generally well tolerated and safe up to 20 and 30 mg per day, with intake preferably in the morning. The compound is completely absorbed after oral intake with Cmax values after 6 hours, undergoes little metabolism and has a terminal elimination half life between 60 and 100 hours. Due to its low potential of interaction, memantine can be combined with acetylcholinesterase inhibitors, the mainstay of current symptomatic treatment of Alzheimer's disease and it is suited in elderly patients receiving multiple drug therapy.

Alzheimer Disease↗
PubMed2005

Memantine: a therapeutic approach in treating Alzheimer's and vascular dementia.

Memantine has been clinically used in the treatment of organic disorders in Germany for over ten years and has now been approved in Europe and also in the US for moderate to severe Alzheimer's disease. The rationale for this indication is strongly related to the physiological and pathological role of glutamate in neurotransmission. Glutamate is an agonist of NMDA, kainate and AMPA (ionotropic) receptors, where its influence on NMDA receptors plays an important role with regard to neuronal plasticity effecting memory and learning. Excessive levels of glutamate result in neurotoxicity, in part by overactivation of NMDA receptors. Memantine acts as an uncompetitive antagonist of NMDA receptors and therefore compensates for this overactivation. Furthermore, memantine is a neuroprotective agent in various animal models based on both neurodegenerative and vascular processes, as it ameliorates cognitive and memory deficits. Memantine was effective and safe in several clinical studies, particularly in Alzheimer's disease. The compound is completely absorbed after oral intake and undergoes little metabolism. Having a low probability for drug-drug interactions, memantine, in principle, is suited for elderly patients exposed to multiple therapeutic therapies.

Alzheimer Disease↗
PubMed2002

Neuroprotective effect of memantine in a rabbit model of optic nerve ischemia.

The purpose of this study was to evaluate the neuroprotective effect of memantine, a N-methyl-D-aspartate antagonist, in an experimental optic nerve ischemia. Endothelin-1 (ET-1) in a dosage of 0.1 microg/day was delivered to the perineural region of the anterior optic nerve by osmotically driven minipumps for 8 weeks in 10 rabbits. In 5 rabbits, 1 mg/kg memantine was administered concurrently by intramuscular injection once a daily. Morphologic optic nerve head changes were monitored with a confocal scanning laser ophthalmoscope. Multivariate statistical analysis showed a significant change in topometric parameters (cup area, cup depth and rim volume), indicating an increase in optic nerve head cupping and a decrease of neural rim volume in the ET-1 administered eyes (P < 0.0001). In rabbits where memantine was given concurrently with ET-1, no significant change in topometric parameters was observed after ET-1 administration (P = 0.78). The current results suggest that memantine has a neuroprotective effect in optic nerve ischemia. Memantine may potentially be useful in the management of various ischemic disorders of the optic nerve, including glaucoma.

Animals↗
PubMedDate not supplied

[Glutamate-related excitotoxicity neuroprotection with memantine, an uncompetitive antagonist of NMDA-glutamate receptor, in Alzheimer's disease and vascular dementia].

AIM: To review the therapeutic efficacy of memantine, an uncompetitive antagonist of N-methyl-D-aspartate (NMDA)-glutamate receptor. DEVELOPMENT: Alzheimer's disease (AD) is the most common neurodegenerative disorder and cause of dementia with ageing worldwide. The main AD symptoms are a gradual loss of cognitive function and a functional impairment. Glutamatergic excitatory neurotransmission, an important process in learning and memory, is severely disrupted in AD, probably due to the oxidative stress associated with the beta-amyloid peptide (1-42) increase. The glutamate-related excitotoxicity, mainly mediated by NMDA subtype of the glutamate receptors, is a common clue of pathogenesis for neurodegenerative disorders. CONCLUSIONS: Memantine, a moderate-affinity, voltage-dependent, uncompetitive antagonist of NMDA receptor, shows neuroprotective effects in patients with moderate-to-severe AD. Memantine is a drug with neuroprotective and cognition-enhanced properties, which can be combined with other treatments for AD. Thus, memantine does not stop or reverse AD, but its moderating effect in protecting the brain from the toxic levels of calcium, allows normal signaling among brain neurons. The efficacy and safety profile of memantine have been reported in several clinical trials for treatment of AD and vascular dementia.

Alzheimer Disease↗
PubMedDate not supplied

[Retrospective comparative analysis of antidementia medication persistence patterns in Spanish Alzheimer's disease patients treated with donepezil, rivastigmine, galantamine and memantine].

INTRODUCTION AND AIM: Dementia of Alzheimer type has become the most frequent type of dementia in our environment. Treatment persistence is a crucial factor to delay patient functional and cognitive impairment. The aim of the present study was to determine treatment persistence in usual care settings with four different antidementia drugs: donepezil, rivastigmine, galantamine and memantine in a cohort of patients with Alzheimer's dementia in Spain. PATIENTS AND METHODS: An Alzheimer type dementia retrospective cohort study was performed in 13 Primary Care Health Centers in Spain. The study included patients treated between January 2000 and March 2005. RESULTS: A total of 299 patients (44.8% female), mean age 77.9 years, were included: 101 donepezil (33.8.%), 105 rivastigmine (35.1%), 51 galantamine (17.1%) and 42 memantine (14.0%). Mean treatment duration was significantly different depending on therapy type, showing higher values for donepezil patients (mean: 83.3 weeks; 95% CI: 72.7-93.9) than for the other cholinesterase inhibitors: rivastigmine (mean: 76.6 weeks; 95% CI: 66.0-87.3), galantamine (mean: 65.8 weeks; 95% CI: 55.3-76.3) and memantine (60.9 weeks; 95% CI: 48.8-73.1), p = 0.049. Overall treatment persistence was significantly different between drugs, with again donepezil showing higher persistence (median time: 70.3 weeks; 95% CI: 49.8-90.7) than with the others drugs: rivastigmine (median time: 56.1 weeks; 95% CI: 36.1-76.2), galantamine (median time: 56.7 weeks; 95% CI: 41.1-72.3) and memantine (median time: 52.1 weeks; 95% CI: 35.2-69.1), log-rank = 10.16; p = 0.017. CONCLUSION: This study showed significative differences in the global treatment persistence among the considered drug-cholinesterase inhibitors, showing higher persistence resulting in patients treated with donepezil compared to those who received rivastigmine, galantamine or memantine.

Aged↗
PubMed1983

[Pharmacodynamics and pharmacokinetics of memantine].

The adamantane derivative memantine (1-amino-3,5-dimethylaminoadamantane, D-145, Akatinol) is clinically used as well in the therapy of neurogenic motor diseases (e.g. spasticity) as in the treatment of cerebral disorders like coma, cerebrovascular and geronto-psychiatric disturbances. The aim of the paper is to summarize experimental evidences that may help to explain the clinical observations. Biochemical, pharmacological, and electrophysiological studies show that memantine interferes with the metabolism of the transmitters dopamine, noradrenaline (norepinephrine), and serotonin and modulates synaptic transMission. In order to explain the antispastic activity of memantine, a spinal action must be assumed in addition to the supraspinal effect on transmitter systems. Since memantine reduces the membrane resistance as well as the membrane conductance of sodium, potassium, and chloride ions, it is very likely that memantine Is directly involved in the generation of action potentials.

Amantadine↗