Psychotropic Drug Development Strategies that Target Neuropsychiatric Etiologies in Alzheimer's and Parkinson's Diseases.

Preclinical Research Neuropsychiatric symptoms are currently recognized as a common burden in patients suffering from Alzheimer's disease (AD), Parkinson's disease (PD), and many other neurodegenerative disorders. Earlier theories positing that these symptoms emerge predominantly in patients with late-stage disease have been largely dismissed. It is now generally accepted that many neuropsychiatric symptoms commonly manifest very early in neurodegenerative disease stages, and in many cases are even considered prodromal indicators.

Synthesis and Biological Evaluation of Pentacycloundecylamines and Triquinylamines as Voltage-Gated Calcium Channel Blockers.

Preclinical studies for neurodegenerative diseases have shown a multi-targeted approach to be successful in the treatment of these complex disorders with several pathoetiological pathways. Polycyclic compounds, such as NGP1-01 (7a), have demonstrated the ability to target multiple mechanisms of the complex etiology and are referred to as multifunctional compounds. These compounds have served as scaffolds with the ability to attenuate Ca(2+) overload and excitotoxicity through several pathways.

Rational drug discovery design approaches for treating Parkinson's disease.

Introduction: Parkinson's disease (PD) is a severe progressive neurodegenerative disorder. As yet, no therapeutic agent can prevent the characteristic neuronal cell loss in PD brain. The introduction of levodopa to the clinic several decades ago has greatly mitigated the symptomatic burden in PD patients.

Abnormal metal levels in the primary visual pathway of the DBA/2J mouse model of glaucoma.

The purpose of this study was to determine metal ion levels in central visual system structures of the DBA/2J mouse model of glaucoma. We used inductively coupled plasma mass spectrometry (ICP-MS) to measure levels of iron (Fe), copper (Cu), zinc (Zn), magnesium (Mg), manganese (Mn), and calcium (Ca) in the retina and retinal projection of 5-month (pre-glaucomatous) and 10-month (glaucomatous) old DBA/2J mice and age-matched C57BL/6J controls. We used microbeam X-ray fluorescence (μ-XRF) spectrometry to determine the spatial distribution of Fe, Zn, and Cu in the superior colliculus (SC), which is the major retinal target in rodents and one of the earliest sites of pathology in the DBA/2J mouse.

Methyl Yellow: A Potential Drug Scaffold for Parkinson's Disease.

Parkinson's disease (PD) is an age-related neurodegenerative disease affecting movement. To date, there are no currently available therapeutic agents which can prevent or slow disease progression. Here, we evaluated an azobenzene derivative, methyl yellow (MY), as a potential drug scaffold for PD; its inhibitory activity toward monoamine oxidase B (MAO-B) as well as drug-like properties were investigated.

Development and validation of an LC-MS/MS method for determination of the L-type voltage-gated calcium channel/NMDA receptor antagonist NGP1-01 in mouse serum.

NGP1-01 (8-benzylamino-8,11-oxapentacyclo[5.4.0.

3D-QSAR and docking studies of pentacycloundecylamines at the sigma-1 (σ1) receptor.

Pentacycloundecylamine (PCU) derived compounds have been shown to be promising lead structures for the development of novel drug candidates aimed at a variety of neurodegenerative and psychiatric diseases. Here we show for the first time a 3D quantitative structure-activity relationship (3D-QSAR) for a series of aza-PCU-derived compounds with activity at the sigma-1 (σ1) receptor. A comparative molecular field analysis (CoMFA) model was developed with a partial least squares cross validated (q(2)) regression value of 0.

Rationally designed multi-targeted agents against neurodegenerative diseases.

Neurodegenerative diseases are complex disorders with several pathoetiological pathways leading to cell death. Rationally designed multi-targeted agents, or "multi-targeted designed drugs" (MTDD) show significant promise in preclinical studies as neuroprotective and disease-modifying agents. In this review, we highlight the use of chemical scaffolds that lend themselves exquisitely to the development of MTDDs in neurodegeneration.

Designing drugs with multi-target activity: the next step in the treatment of neurodegenerative disorders.

Introduction: Neurodegenerative diseases have had devastating effects on patients' quality of life. These complex diseases have several pathways that are affected to initiate cell death. Current therapies, designed to address only a single target, fall short in mitigating or preventing disease progression, and disease-modifying drugs are desperately needed.

Inhibition of monoamine oxidase by derivatives of piperine, an alkaloid from the pepper plant Piper nigrum, for possible use in Parkinson's disease.

A series of compounds related to piperine and antiepilepsirine was screened in a monoamine oxidase A and B assay. Piperine is an alkaloid from the source plant of both black and white pepper grains, Piper nigrum. Piperine has been shown to have a wide range of activity, including MAO inhibitory activity.

NGP1-01, a multi-targeted polycyclic cage amine, attenuates brain endothelial cell death in iron overload conditions.

Development and progression of neurodegenerative disorders have, amongst other potential causes, been attributed to a disruption of iron regulatory mechanisms and iron accumulation. Excess extracellular iron may enter cells via nontraditional routes such as voltage-gated calcium channels and N-methyl-d-aspartate (NMDA) receptors leading to intracellular oxidative damage and ultimately mitochondrial failure. Nimodipine, an L-type calcium channel blocker has been shown to reduce iron-induced toxicity in neuronal and brain endothelial cells.

Curcumin and neurodegenerative diseases: a perspective.

Introduction: Curcumin, a dietary polyphenol found in the curry spice turmeric, possesses potent antioxidant and anti-inflammatory properties and an ability to modulate multiple targets implicated in the pathogenesis of chronic illness. Curcumin has shown therapeutic potential for neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD).

Areas Covered: This article highlights the background and epidemiological evidence of curcumin's health benefits and its pharmacodynamic and pharmacokinetic profile.

Polycyclic cage structures as lipophilic scaffolds for neuroactive drugs.

Polycyclic cage scaffolds have been successfully used in the development of numerous lead compounds demonstrating activity in the central nervous system (CNS). Several neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, schizophrenia, and stroke, as well as drug abuse, can be modulated with polycyclic cage derivatives. These cage moieties, including adamantane and pentacycloundecane derivatives, improve the pharmacokinetic and pharmacodynamic properties of conjugated parent drugs and serve as an important scaffold in the design of therapeutically active agents for the treatment of neurological disorders.

A scaffold hopping approach to identify novel monoamine oxidase B inhibitors.

Monoamine oxidase B (MAO-B) inhibitors are used to treat Parkinson's disease. In this study, we searched for novel MAO-B inhibitors using a scaffold hopping approach based on our experience with the thiazolidinedione (TZD) class of compounds as MAO-B inhibitors. Several novel compounds were identified, with potencies in the low nanomolar and low micromolar range.

Multimodal drugs and their future for Alzheimer's and Parkinson's disease.

This chapter discusses the rationale for developing multimodal or multifunctional drugs (also called designed multiple ligands or DMLs) aimed at disease-modifying treatment strategies for the most common neurodegenerative diseases Alzheimer's and Parkinson's disease (AD and PD). Both the prevalence and incidence of AD and PD have seen consistent and dramatic increases, a disconcerting phenomenon which, ironically, has been attributed to extended life expectancy brought about by better health care globally. In spite of these statistics, the development and introduction to the clinic of new therapies proven to prevent or delay the onset of AD and PD have been disappointing.

Differential effect of nimodipine in attenuating iron-induced toxicity in brain- and blood-brain barrier-associated cell types.

Metal homeostasis is increasingly being evaluated as a therapeutic target in stroke and neurodegenerative diseases. Metal dysregulation has been shown to lead to protein aggregation, plaque formation and neuronal death. In 2007, we first reported that voltage-gated calcium channels act as a facile conduit for the entry of free ferrous (Fe(2+)) ions into neurons.

Role of serotonin in Alzheimer's disease: a new therapeutic target?

Mounting evidence accumulated over the past few years indicates that the neurotransmitter serotonin plays a significant role in cognition. As a drug target, serotonin receptors have received notable attention due in particular to the role of several serotonin-receptor subclasses in cognition and memory. The intimate anatomical and neurochemical association of the serotonergic system with brain areas that regulate memory and learning has directed current drug discovery programmes to focus on this system as a major therapeutic drug target.

The emergence of designed multiple ligands for neurodegenerative disorders.

The incidence of neurodegenerative diseases has seen a constant increase in the global population, and is likely to be the result of extended life expectancy brought about by better health care. Despite this increase in the incidence of neurodegenerative diseases, there has been a dearth in the introduction of new disease-modifying therapies that are approved to prevent or delay the onset of these diseases, or reverse the degenerative processes in brain. Mounting evidence in the peer-reviewed literature shows that the etiopathology of these diseases is extremely complex and heterogeneous, resulting in significant comorbidity and therefore unlikely to be mitigated by any drug acting on a single pathway or target.

In vivo brain microdialysis: advances in neuropsychopharmacology and drug discovery.

INTRODUCTION: Microdialysis is an important in vivo sampling technique, useful in the assay of extracellular tissue fluid. The technique has both pre-clinical and clinical applications but is most widely used in neuroscience. The in vivo microdialysis technique allows measurement of neurotransmitters such as acetycholine (ACh), the biogenic amines including dopamine (DA), norepinephrine (NE) and serotonin (5-HT), amino acids such as glutamate (Glu) and gamma aminobutyric acid (GABA), as well as the metabolites of the aforementioned neurotransmitters, and neuropeptides in neuronal extracellular fluid in discrete brain regions of laboratory animals such as rodents and non-human primates.

The styrene metabolite, phenylglyoxylic acid, induces striatal-motor toxicity in the rat: influence of dose escalation/reduction over time.

Exposure to the industrial solvent, styrene, induces locomotor and cognitive dysfunction in rats, and parkinsonian-like manifestations in man. The antipsychotic, haloperidol (HP), well known to induce striatal toxicity in man and animals, and styrene share a common metabolic pathway yielding p-fluoro phenylglyoxylic acid and phenylglyoxylic acid (PGA), respectively. Using an exposure period of 30 days and the vacous chewing movement (VCM) model as an expression of striatal-motor toxicity, we found that incremental PGA dosing (220-400 mg/kg) significantly increased VCMs up to day 25, but decreased to control levels shortly after reaching maximum dose.

Identification of novel monoamine oxidase B inhibitors by structure-based virtual screening.

Parkinson's disease is a severe debilitating neurodegenerative disorder. Recently, it was shown that the peroxisome proliferating-activator receptor-gamma agonist pioglitazone protected mice from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine neurotoxicity due to its ability to inhibit monoamine oxidase B (MAO-B). Docking studies were initiated to investigate pioglitazone's interactions within the substrate cavity of MAO-B.

Oxidative stress and Alzheimer's disease: dietary polyphenols as potential therapeutic agents.

Oxidative stress has been strongly implicated in the pathophysiology of neurodegenerative disorders such as Alzheimer's disease (AD). In recent years, antioxidants - especially those of dietary origin - have been suggested as possible agents useful for the prevention and treatment of AD. This article reviews the role of oxidative stress and the contribution of free radicals in the development of AD, and also discusses the use of antioxidants as a therapeutic strategy in the amelioration of this illness.

Predictive screening model for potential vector-mediated transport of cationic substrates at the blood-brain barrier choline transporter.

A set of semi-rigid cyclic and acyclic bis-quaternary ammonium analogs, which were part of a drug discovery program aimed at identifying antagonists at neuronal nicotinic acetylcholine receptors, were investigated to determine structural requirements for affinity at the blood-brain barrier choline transporter (BBB CHT). This transporter may have utility as a drug delivery vector for cationic molecules to access the central nervous system. In the current study, a virtual screening model was developed to aid in rational drug design/ADME of cationic nicotinic antagonists as BBB CHT ligands.

Nicotine exacerbates brain edema during in vitro and in vivo focal ischemic conditions.

We have previously shown that nicotine, the addictive component of tobacco products, alters the blood-brain barrier (BBB) Na(+),K(+),2Cl(-) cotransporter (NKCC) during in vitro hypoxia-aglycemia exposure. Attenuation of abluminal NKCC suggests that accumulation of ions in the brain extracellular fluid would result in an increase of fluid or cytotoxic edema in the brain during hypoxia-aglycemia or stroke conditions. To further investigate whether nicotine products have the potential to worsen stroke outcome by increasing edema formation, two separate models to mimic stroke conditions were utilized to decipher the effects of short-term and long-term administrations of nicotine products on brain edema following stroke.