Potential cognitive actions of (n-propargly-(3r)-aminoindan-5-yl)-ethyl, methyl carbamate (tv3326), a novel neuroprotective agent, as assessed in old rhesus monkeys in their performance of versions of a delayed matching task

Advances in prodrug design for Alzheimer's Disease: the state of the art

INTRODUCTION

: Alzheimer's disease (AD) is the most common cause of dementia with a memory loss and other cognitive abilities and is a complex and multifactorial neurodegenerative disease that remains today a challenge for drug discovery. Like many pathologies of the central nervous system, one of the first hurdles is the development of a compound with a sufficient brain exposure to ensure a potential therapeutic benefit. In this direction, the development of prodrugs has been an intense field of research in the last years.

AREAS COVERED

: Two main strategies of prodrugs development are analysed in this review. First, the application of the classical modulation of an active compound to incorporate a drug carrier or to prepare bioprecursor has been exemplified in the field of AD. This approach has led to several examples engaged in the clinical trials. In a second chapter, a series of innovative prodrugs based on a polypharmacological approach is described to take into account the complexity of AD.

EXPERT OPINION

: In the past 10 years, at least 6 prodrugs have been approved by the FDA for the treatment of central nervous system pathologies. Most of them have been developed in order to improve membrane permeability of the parent drugs. Facing the limitation of Alzheimer's disease drug discovery, the development of prodrugs will likely play a central role in the next years. Indeed, beside addressing the challenge of distribution, prodrug could also tackle the complex multifactorial origin of the disease with the rise of innovative pleiotropic prodrugs.

Exploring the Multifunctional Neuroprotective Promise of Rasagiline Derivatives for Multi-Dysfunctional Alzheimer's Disease

Alzheimer's disease (AD) is a chronic, age-related, and irreversible brain disorder that typically develops slowly and gets worse over time. The potent auspicious drug candidate for the treatment of AD is supposed to perform the simultaneous modulation of several targets linked to AD. The new therapeutic approach involves drug candidates that are designed to act on multiple targets and have various pharmacological properties. This trend has triggered the development of various multimodal drugs including TV-3326 (i.e. ladostigil) and M-30 (i.e. a new multitarget iron chelator). TV-3326 combines the neurorestorative/neuroprotective effects of the cholinesterase (ChE) inhibitory activity of rivastigmine with rasagiline (a selective monoamine oxidase-B inhibitor and novel antiparkinsonian agent) in a single molecule. M-30, the second derivative of rasagiline, was developed by combining the propargyl moiety of rasagiline into the skeleton of VK-28 (i.e. a novel brain permeable neuroprotective iron chelator). It has been revealed that both the compounds possess anti-AD effects and therefore, the clinical development is directed to the treatment of this type of neurodegenerative diseases (NDs). In this article, we have reviewed the neuroprotective molecular mechanisms and multimodal effects of TV-3326 and M-30.

A comprehensive review of monoamine oxidase inhibitors as Anti-Alzheimer's disease agents: A review

Monoamine oxidases (MAO-A and MAO-B) are mammalian flavoenzyme, which catalyze the oxidative deamination of several neurotransmitters like norepinephrine, dopamine, tyramine, serotonin, and some other amines. The oxidative deamination produces several harmful side products like ammonia, peroxides, and aldehydes during the biochemical reaction. The concentration of biochemical neurotransmitter alteration in the brain by MAO is directly related with several neurological disorders like Alzheimer's disease and Parkinson's disease (PD). Activated MAO also contributes to the amyloid beta (Aβ) aggregation by two successive cleft β-secretase and γ-secretase of amyloid precursor protein (APP). Additionally, activated MAO is also involved in aggregation of neurofibrillary tangles and cognitive destruction through the cholinergic neuronal damage and disorder of the cholinergic system. MAO inhibition has general anti-Alzheimer's disease effect as a consequence of oxidative stress reduction prompted by MAO enzymes. In this review, we outlined and addressed recent understanding on MAO enzymes such as their structure, physiological function, catalytic mechanism, and possible therapeutic goals in AD. In addition, it also highlights the current development and discovery of potential MAO inhibitors (MAOIs) from various chemical scaffolds.

TV 3326 for Alzheimer's dementia: a novel multimodal ChE and MAO inhibitors to mitigate Alzheimer's-like neuropathology

OBJECTIVES

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative disorders and a well-recognized cause of dementia with ageing. In this review, we have represented the ChE and MAO inhibitory potential of TV 3326 against AD based on current scientific evidence.

KEY FINDINGS

The aetiology of AD is quite complex and not completely understood. However, it has been observed that AD involves the deposition of abnormal amyloid beta (Aβ), along with hyperphosphorylation of tau, oxidative stress, low acetylcholine (ACh) level and biometal dyshomeostasis. Due to the complex nature of AD aetiology, active research is required in the areas of development of multitarget drugs with 2 or more complementary biological functions, as they might represent significant progress in the AD treatment. Interestingly, it has been found that TV 3326 (i.e. ladostigil) is regarded as a novel therapeutic agent since it has the potential to cause inhibition of monoamine oxidase (MAO) A and B, and acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in the brain. Furthermore, it has the capacity to reverse memory impairments, which further suggests the ability of this drug to elevate cholinergic activity in the brain.

SUMMARY

TV 3326 can avert oxidative-nitrative stress and gliosis. It has also been confirmed that TV 3326 contains neuroprotective and anti-apoptotic properties. Therefore, this distinctive combined inhibition of ChE and MAO along with its neuroprotective property makes TV 3326 a useful drug in the treatment of AD.

Inhibitors of MAO-A and MAO-B in Psychiatry and Neurology

Inhibitors of MAO-A and MAO-B are in clinical use for the treatment of psychiatric and neurological disorders respectively. Elucidation of the molecular structure of the active sites of the enzymes has enabled a precise determination of the way in which substrates and inhibitor molecules are metabolized, or inhibit metabolism of substrates, respectively. Despite the knowledge of the strong antidepressant efficacy of irreversible MAO inhibitors, their clinical use has been limited by their side effect of potentiation of the cardiovascular effects of dietary amines (“cheese effect”). A number of reversible MAO-A inhibitors which are devoid of cheese effect have been described in the literature, but only one, moclobemide, is currently in clinical use. The irreversible inhibitors of MAO-B, selegiline and rasagiline, are used clinically in treatment of Parkinson's disease, and a recently introduced reversible MAO-B inhibitor, safinamide, has also been found efficacious. Modification of the pharmacokinetic characteristics of selegiline by transdermal administration has led to the development of a new drug form for treatment of depression. The clinical potential of MAO inhibitors together with detailed knowledge of the enzyme's binding site structure should lead to future developments with these drugs.

Multi-target therapeutics for neuropsychiatric and neurodegenerative disorders

Historically, neuropsychiatric and neurodegenerative disease treatments focused on the 'magic bullet' concept; however multi-targeted strategies are increasingly attractive gauging from the escalating research in this area. Because these diseases are typically co-morbid, multi-targeted drugs capable of interacting with multiple targets will expand treatment to the co-morbid disease condition. Despite their theoretical efficacy, there are significant impediments to clinical success (e.g., difficulty titrating individual aspects of the drug and inconclusive pathophysiological mechanisms). The new and revised diagnostic frameworks along with studies detailing the endophenotypic characteristics of the diseases promise to provide the foundation for the circumvention of these impediments. This review serves to evaluate the various marketed and nonmarketed multi-targeted drugs with particular emphasis on their design strategy.

Neuroprotective effects of multifaceted hybrid agents targeting MAO, cholinesterase, iron and β-amyloid in ageing and Alzheimer's disease

Alzheimer's disease (AD) is accepted nowadays as a complex neurodegenerative disorder with multifaceted cerebral pathologies, including extracellular deposition of amyloid β peptide-containing plaques, intracellular neurofibrillary tangles, progressive loss of cholinergic neurons, metal dyshomeostasis, mitochondrial dysfunction, neuroinflammation, glutamate excitoxicity, oxidative stress and increased MAO enzyme activity. This may explain why it is currently widely accepted that a more effective therapy for AD would result from the use of multifunctional drugs, which may affect more than one brain target involved in the disease pathology. The current review will discuss the potential benefits of novel multimodal neuroprotective, brain permeable drugs, recently developed by Youdim and collaborators, as a valuable therapeutic approach for AD treatment. The pharmacological and neuroprotective properties of these multitarget-directed ligands, which target MAO enzymes, the cholinergic system, iron accumulation and amyloid β peptide generation/aggregation are described, with a special emphasis on their potential therapeutic value for ageing and AD-associated cognitive functions. This review is conceived as a tribute to the broad neuropharmacology work of Professor Moussa Youdim, Professor Emeritus in the Faculty of Medicine and Director of Eve Topf Center of Excellence in Technion-Israel Institute of Technology, and Chief Scientific Officer of ABITAL Pharma Pipeline Ltd., at the occasion of his 75th birthday.

LINKED ARTICLES

This article is part of a themed section on Updating Neuropathology and Neuropharmacology of Monoaminergic Systems. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.13/issuetoc.

Neuroprotective and neurorestorative potential of propargylamine derivatives in ageing: focus on mitochondrial targets

The mitochondrial theory of ageing proposes that accumulation of damage to mitochondrial function and DNA mutation lead to ageing of humans and animals. It has been suggested that mitochondria play dynamic roles in regulating synaptogenesis and morphological/functional responses of synaptic activity, and thus, deteriorating of mitochondrial function (e.g., deficits of the mitochondrial respiratory enzymes, reduced calcium influx, increased accumulation of mitochondrial DNA defects/apoptotic proteins and impairment of mitochondrial membrane potential) can lead to severe neuronal energy deficit, and in the long run, to modifications in neuronal synapses and neurodegeneration in the ageing brain. Hence, considering the mechanisms by which mitochondrial impairment can lead to neuronal death, the development of neuroprotective molecules that target various mitochondrial pathogenic processes can be effective in the treatment of ageing and age-related neurodegenerative diseases. This review addresses several aspects of the neuroprotective effects of propargylamine derivatives (e.g., the monoamine oxidase-B inhibitors, selegiline and rasagiline and the multifunctional drugs, ladostigil, M30 and VAR10303) in ageing with a special focus on mitochondrial molecular protective mechanisms.

Muscarinic receptor occupancy and cognitive impairment: a PET study with [11C](+)3-MPB and scopolamine in conscious monkeys

The muscarinic cholinergic receptor (mAChR) antagonist scopolamine was used to induce transient cognitive impairment in monkeys trained in a delayed matching to sample task. The temporal relationship between the occupancy level of central mAChRs and cognitive impairment was determined. Three conscious monkeys (Macaca mulatta) were subjected to positron emission tomography (PET) scans with the mAChR radioligand N-[(11)C]methyl-3-piperidyl benzilate ([(11)C](+)3-MPB). The scan sequence was pre-, 2, 6, 24, and 48 h post-intramuscular administration of scopolamine in doses of 0.01 and 0.03 mg/kg. Occupancy levels of mAChR were maximal 2 h post-scopolamine in cortical regions innervated primarily by the basal forebrain, thalamus, and brainstem, showing that mAChR occupancy levels were 43-59 and 65-89% in doses of 0.01 and 0.03 mg/kg, respectively. In addition, dose-dependent impairment of working memory performance was measured 2 h after scopolamine. A positive correlation between the mAChR occupancy and cognitive impairment 2 and 6 h post-scopolamine was the greatest in the brainstem (P<0.00001). Although cognitive impairment was not observed 24 h post-scopolamine, sustained mAChR occupancy (11-24%) was found with both doses in the basal forebrain and thalamus, but not in the brainstem. These results indicate that a significant degree of mAChRs occupancy is needed to produce cognitive impairment by scopolamine. Furthermore, the importance of the brainstem cholinergic system in working memory in monkey is described.

Titrating-delay matching-to-sample in the pigeon

The titrating-delay matching-to-sample (TDMTS) procedure offers researchers an additional behavioral task thought to capture some important features of remembering. In this procedure, the delay between sample offset and comparison onset adjusts as a function of the subject's performance. Specifically, correct matches increase the delay and incorrect matches decrease the delay, and steady-state titrated delays serve as the primary dependent measure. The present series of experiments investigated the effects of several procedural variables on performance in TDMTS procedures in an effort to elucidate better its features to allow for more precision in future use. Experiment 1 reports results from a parametric analysis of fixed-ratio response requirements on the sample key that indicated improved remembering in the form of higher daily titrated delay values as the requirement was increased. Experiment 2 investigated the extent to which the initial delay value in each session affected session-wide delay values. Results indicated that regardless of value of the initial delay, the subjects' performances adjusted the delay values in the direction of the known baseline delay-value levels. Experiment 3 manipulated the step size by which delay values were adjusted and the results indicated that larger step sizes increased both session-to-session variability and within-session range of titrated delay values, although the average values remained approximately the same. These results suggest that the TDMTS task serves as a promising procedure to study what many refer to as memory.

Alzheimer's disease and age-related memory decline (preclinical)

An unfortunate result of the rapid rise in geriatric populations worldwide is the increasing prevalence of age-related cognitive disorders such as Alzheimer's disease (AD). AD is a devastating neurodegenerative illness that is characterized by a profound impairment of cognitive function, marked physical disability, and an enormous economic burden on the afflicted individual, caregivers, and society in general. The rise in elderly populations is also resulting in an increase in individuals with related (potentially treatable) conditions such as "Mild Cognitive Impairment" (MCI) which is characterized by a less severe (but abnormal) level of cognitive impairment and a high-risk for developing dementia. Even in the absence of a diagnosable disorder of cognition (e.g., AD and MCI), the perception of increased forgetfulness and declining mental function is a clear source of apprehension in the elderly. This is a valid concern given that even a modest impairment of cognitive function is likely to be associated with significant disability in a rapidly evolving, technology-based society. Unfortunately, the currently available therapies designed to improve cognition (i.e., for AD and other forms of dementia) are limited by modest efficacy and adverse side effects, and their effects on cognitive function are not sustained over time. Accordingly, it is incumbent on the scientific community to develop safer and more effective therapies that improve and/or sustain cognitive function in the elderly allowing them to remain mentally active and productive for as long as possible. As diagnostic criteria for memory disorders evolve, the demand for pro-cognitive therapeutic agents is likely to surpass AD and dementia to include MCI and potentially even less severe forms of memory decline. The purpose of this review is to provide an overview of the contemporary therapeutic targets and preclinical pharmacologic approaches (with representative drug examples) designed to enhance memory function.

Multifunctional receptor-directed drugs for disorders of the central nervous system

The marked decline in FDA-approved new drug candidates in recent years suggests the possibility that the "low-hanging fruit" has been almost entirely harvested. This might be particularly applicable to drugs acting on the central nervous system. Fortunately, there are several examples extant for the utility of multifunctional drugs, compounds, or drug mixtures that act on multiple additive or synergistic targets. However, to exploit this approach may require the willingness to consider the possibility that drug targets might be addressed by molecules of rather low specificity and moderate potency. The expectation is that single target molecules with high specificity might not have access to complex interacting neural pathways, and that moderate potency could engender fewer off-target side effects. Though novel compounds might be developed by combining the active functional groups of two or more drug molecules, the approach still lends itself to high throughput screening of large chemical libraries. Multifunctional compounds might be designed with the ability to: 1) offer both palliative and disease modifying actions, 2) act on targets that produce additive or synergistic therapeutic responses, 3) simultaneously evoke a therapeutic response at the desired target and prevent an undesired response mediated by an alternate target, 4) allow one component to promote the drugable characteristics (e.g., brain penetration) of the therapeutic component, and 5) prolong the duration of effectiveness of one compound by contributing the pharmacodynamic actions of another. The author takes the liberty to include examples of the situations just mentioned from studies in his laboratory in the following discussion.

Multifunctional neuroprotective derivatives of rasagiline as anti-Alzheimer's disease drugs

The recent therapeutic approach in which drug candidates are designed to possess diverse pharmacological properties and act on multiple targets has stimulated the development of the multimodal drugs, ladostigil (TV3326) [(N-propargyl-(3R) aminoindan-5yl)-ethyl methyl carbamate] and the newly designed multifunctional antioxidant iron chelator, M-30 (5-[N-methyl-N-propargylaminomethyl]-8-hydroxyquinoline). Ladostigil combines, in a single molecule, the neuroprotective/neurorestorative effects of the novel anti-Parkinsonian drug and selective monoamine oxidase (MAO)-B inhibitor, rasagiline (Azilect, Teva Pharmaceutical Co.) with the cholinesterase (ChE) inhibitory activity of rivastigmine. A second derivative of rasagiline, M-30 was developed by amalgamating the propargyl moiety of rasagiline into the skeleton of our novel brain permeable neuroprotective iron chelator, VK-28. Preclinical experiments showed that both compounds have anti-Alzheimer's disease activities and thus, the clinical development is oriented toward treatment of this type of dementia. This review discusses the multimodal effects of two rasagiline-containing hybrid molecules, namely ladostigil and M-30, concerning their neuroprotective molecular mechanisms in vivo and in vitro, including regulation of amyloid precursor protein processing, activation of protein kinase C, and mitogen-activated protein kinase signaling pathways, inhibition of cell death markers and upregulation of neurotrophic factors. Altogether, these scientific findings make these multifunctional compounds potentially valuable drugs for the treatment of Alzheimer's disease.

Profile of nicotinic acetylcholine receptor agonists ABT-594 and A-582941, with differential subtype selectivity, on delayed matching accuracy by young monkeys

ABT-594 and A-582941 are high affinity neuronal nicotinic acetylcholine receptor agonists with differential selectivity for the alpha4beta2 and the alpha7 subtypes, respectively. This study was designed to determine whether either compound, like nicotine also possesses cognitive-enhancing ability. The compounds were administered by intramuscular injection to young adult Rhesus monkeys trained to perform two versions of a computer-assisted delayed matching-to-sample (DMTS) task. ABT-594 (0.115-3.7 microg/kg) significantly improved DMTS accuracies, shifting the retention curve (accuracy-delay relationship) to the right in a parallel fashion. DMTS accuracy also was maintained during the sessions initiated 24h after compound administration. Because task accuracy was improved during short delay trials, a separate study was performed in which non-predictable distractors were inserted within the DMTS format to impair accuracy. The 0.115 microg/kg dose of ABT-594 almost completely reversed distractor-impaired performance associated with short delay trials. The alpha7 nAChR agonist, A-582941 (1.14-38 microg/kg) also significantly improved DMTS accuracies. The compound produced a significant improvement during long delay trials. The effect was twice as robust for long delay as compared with short delay trials and A-582941 was not as effective as ABT-594 in improving short delay trial accuracy. A-582941 also failed to sustain task improvement during sessions run 24h after dosing. These data are consistent with the ability of subtype-preferring nicotinic receptor agonists to enhance specific components of working memory and cognitive function, and they suggest that differential subtype selectivity could result in varied pharmacological response profiles.

Aminoindan and hydroxyaminoindan, metabolites of rasagiline and ladostigil, respectively, exert neuroprotective properties in vitro

The anti-Parkinson, selective irreversible monoamine oxidase B inhibitor drug, rasagiline (Azilect), recently approved by the US Food and Drug Administration, has been shown to possess neuroprotective-neurorescue activities in in vitro and in vivo models. Recent preliminary studies indicated the potential neuroprotective effect of the major metabolite of rasagiline, 1-(R)-aminoindan. In the current study, the neuroprotective properties of 1-(R)-aminoindan were assessed employing a cytotoxic model of human neuroblastoma SK-N-SH cells in high-density culture-induced neuronal death. We show that aminoindan (0.1-1 mumol/L) significantly reduced the apoptosis-associated phosphorylated protein, H2A.X (Ser139), decreased the cleavage of caspase 9 and caspase 3, while increasing the anti-apoptotic proteins, Bcl-2 and Bcl-xl. Protein kinase C (PKC) inhibitor, GF109203X, prevented the neuroprotection, indicating the involvement of PKC in aminoindan-induced cell survival. Aminoindan markedly elevated pPKC(pan) and specifically that of the pro-survival PKC isoform, PKCepsilon. Additionally, hydroxyaminoindan, a metabolite of a novel bifunctional drug, ladostigil [(N-propargyl-(3R) aminoindan-5yl)-ethyl methyl carbamate], combining cholinesterase and monoamine oxidase inhibitor activity, exerted similar neuroprotective properties. Aminoindan and hydroxyaminoindan also protected rat pheochromacytoma PC-12 cells against the neurotoxin, 6-hydroxydopamine. Our findings suggest that both metabolites may contribute to the overall neuroprotective activity of their respective parent compounds, further implicating rasagiline and ladostigil as potentially valuable drugs for treatment of a wide variety of neurodegenerative disorders of aging.

Novel cholinesterase inhibitors as future effective drugs for the treatment of Alzheimer's disease

Current pharmacotherapy for Alzheimer's disease involves compounds that are aimed at increasing the levels of acetylcholine in the brain by facilitating cholinergic neurotransmission through inhibition of cholinesterase. These drugs, known as acetylcholinesterase inhibitors, have been shown to improve cognition and global functions but have little impact on improving the eventual progression of the disease; however, there is evidence that other cholinesterases such as butyrylcholinesterase can play an important role in cholinergic function in the brain, and the long-suspected non-cholinergic actions of acetylcholinesterase, mainly the interference with the beta-amyloid protein cascade, have recently driven a profound revolution in cholinesterase drug research. Several disease-modifying agents are under development that target these enzymes and have hope of becoming the next generation of effective drugs in the treatment of Alzheimer's disease.

The therapeutic potential of monoamine oxidase inhibitors

Monoamine oxidase inhibitors were among the first antidepressants to be discovered and have long been used as such. It now seems that many of these agents might have therapeutic value in several common neurodegenerative conditions, independently of their inhibition of monoamine oxidase activity. However, many claims and some counter-claims have been made about the physiological importance of these enzymes and the potential of their inhibitors. We evaluate these arguments in the light of what we know, and still have to learn, of the structure, function and genetics of the monoamine oxidases and the disparate actions of their inhibitors.

Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application

Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a high social cost. Depressed patients generally display co-morbid symptoms, and depression frequently accompanies other serious disorders. Currently available drugs display limited efficacy and a pronounced delay to onset of action, and all provoke distressing side effects. Cloning of the human genome has fuelled expectations that symptomatic treatment may soon become more rapid and effective, and that depressive states may ultimately be "prevented" or "cured". In pursuing these objectives, in particular for genome-derived, non-monoaminergic targets, "specificity" of drug actions is often emphasized. That is, priority is afforded to agents that interact exclusively with a single site hypothesized as critically involved in the pathogenesis and/or control of depression. Certain highly selective drugs may prove effective, and they remain indispensable in the experimental (and clinical) evaluation of the significance of novel mechanisms. However, by analogy to other multifactorial disorders, "multi-target" agents may be better adapted to the improved treatment of depressive states. Support for this contention is garnered from a broad palette of observations, ranging from mechanisms of action of adjunctive drug combinations and electroconvulsive therapy to "network theory" analysis of the etiology and management of depressive states. The review also outlines opportunities to be exploited, and challenges to be addressed, in the discovery and characterization of drugs recognizing multiple targets. Finally, a diversity of multi-target strategies is proposed for the more efficacious and rapid control of core and co-morbid symptoms of depression, together with improved tolerance relative to currently available agents.

Ladostigil, a novel multifunctional drug for the treatment of dementia co-morbid with depression

Ladostigil is a novel drug that inhibits acetyl and butyrylcholinesterase, and monoamine oxidase (MAO) A and B selectively in the brain. It reverses memory deficits induced by chronic inhibition of cortical cytochrome oxidase in rats and has anxiolytic and antidepressant-like activity in prenatally-stressed rats. Ladostigil also prevents oxidative-nitrative stress induced in astrocytes in the hippocampal CA1 region following icv injection of STZ in rats which also impairs their episodic memory. The unique combination of ChE and MAO enzyme inhibition combined with neuroprotection makes ladostigil a potentially useful drug for the treatment of dementia in subjects that also have extrapyramidal dysfunction and depression.

Multi-functional drugs for various CNS targets in the treatment of neurodegenerative disorders

Individuals with neurodegenerative diseases such as Parkinson's disease or Alzheimer's disease are benefiting from drugs developed to act on a single molecular target. However, current pharmacological approaches are limited in their ability to modify significantly the course of the disease, and offer incomplete and transient benefit to patients. New therapeutic strategies comprise drug candidates designed specifically to act on multiple neural and biochemical targets for the treatment of cognition impairment, motor dysfunction, depression and neurodegeneration. Examples include the development of single molecular entities that combine two or more of the following properties: (i) cholinesterase inhibition; (ii) activation or inhibition of specific subtypes of acetylcholine receptors or alpha-adrenoceptors; (iii) anti-inflammatory activity; (iv) monoamine oxidase inhibition; (v) catechol-O-methyl transferase inhibition; (vi) nitric oxide production; (vii) neuroprotection; (viii) anti-apoptotic activity; and (ix) activation of mitochondrial-dependent cell-survival genes and proteins. These bi- or multi-functional compounds might provide greater symptomatic efficacy, and better utility as potential neuroprotective disease-modifying drugs.

Effect of chronic treatment with ladostigil (TV-3326) on anxiogenic and depressive-like behaviour and on activity of the hypothalamic-pituitary-adrenal axis in male and female prenatally stressed rats

OBJECTIVE

The aim of the study is to investigate the effect of ladostigil, a cholinesterase and brain-selective monoamine oxidase (MAO) inhibitor, on anxiogenic and depressive-like behaviour and the response of the hypothalamic-pituitary-adrenal axis to stress in prenatally stressed (PS) male and female rats.

METHODS

Ladostigil (17 mg/kg/day) was administered daily for 6 weeks to control and PS rats aged 6 weeks. Behaviour was assessed in the elevated plus maze (EPM) and forced swim tests (FST). Plasma corticosterone (COR) was measured before, 30 and 90 min after exposure to stress.

RESULTS

Ladostigil inhibited brain MAO-A and B by more than 60%, significantly reduced hyperanxiety of male and female PS rats in the EPM and depressive-like behaviour in the FST without affecting that of controls and restored the delayed return to baseline of plasma COR in PS rats after exposure to stress to that of control rats.

CONCLUSIONS

A novel brain-selective MAO inhibitor, ladostigil can selectively reverse the behavioural and neurochemical effects induced by prenatal stress without affecting the behaviour of controls.