Psychoactive Substances of Natural Origin: Toxicological Aspects, Therapeutic Properties and Analysis in Biological Samples.

The consumption of new psychoactive substances (NPSs) has been increasing, and this problem affects several countries worldwide. There is a class of NPSs of natural origin, consisting of plants and fungi, which have a wide range of alkaloids, responsible for causing relaxing, stimulating or hallucinogenic effects. The consumption of some of these substances is prompted by religious beliefs and cultural reasons, making the legislation very variable or even ambiguous. However, the abusive consumption of these substances can present an enormous risk to the health of the individuals, since their metabolism and effects are not yet fully known. Additionally, NPSs are widely spread over the internet, and their appearance is very fast, which requires the development of sophisticated analytical methodologies, capable of detecting these compounds. Thus, the objective of this work is to review the toxicological aspects, traditional use/therapeutic potential and the analytical methods developed in biological matrices in twelve plant specimens (Areca catechu, Argyreia nervosa, Ayahuasca, Catha edulis, Datura stramonium, Lophophora williamsii, Mandragora officinarum, Mitragyna speciosa, Piper methysticum Forst, Psilocybe, Salvia divinorum and Tabernanthe iboga).

Evaluation of Juvenile Animal Studies for Pediatric CNS-Targeted Compounds: A Regulatory Perspective.

Central nervous system (CNS)-targeted products are an important category of pediatric pharmaceuticals. In view of the significant postnatal maturation of the CNS, juvenile animal studies (JAS) are performed to support pediatric development of these new medicines. In this project, the design and results of juvenile toxicity studies from 15 drug compounds for the treatment of neurologic or psychiatric conditions were analyzed. Studies were conducted mostly in rats; sometimes in addition in dogs and monkeys. The study design of the pivotal JAS was variable, even for compounds with a similar therapeutic indication. Age of the juvenile animals was not consistently related to the starting age of the intended patient population. Of 15 compounds analyzed, 6 JAS detected more severe toxicities and 6 JAS evidenced novel CNS effects compared to their adult counterparts. The effects of CNS on acoustic startle and learning and memory were observed at high dosages. Reversibility was tested in most cases and revealed some small effects that were retained or only uncovered after termination of treatment. The interpretation of the relevance of these findings was often hampered by the lack of matching end points in the adult studies or inappropriate study designs. Detailed clinical observation and motor activity measures were the most powerful end points to detect juvenile CNS effects. The need for more detailed behavioral examinations in JAS, for example, on learning and memory, should, therefore, be decided upon on a case-by-case basis, based on specific concerns in order to avoid overloading the studies.

CDER Experience With Juvenile Animal Studies for CNS Drugs.

A survey was undertaken to evaluate juvenile animal studies conducted for drug applications reviewed by the Center for Drug Evaluation and Research between 2009 and 2014. Some conclusions about the nonclinical pediatric safety assessment based on studies performed in support of central nervous system-active compounds are presented here. A total of 44 completed studies from 32 New Drug Applications submitted to the Divisions of Psychiatry and Neurology Products were evaluated. Data on animal species and age range used, endpoints evaluated, and outcomes included in labeling were analyzed. Of the drugs evaluated, all but one had studies conducted in rats. In some cases, a second study in a nonrodent species (dog) was also conducted. Indices of growth and development and standard general toxicity parameters were included in all of the studies. Expanded neurohistopathology evaluations, bone mineral density measurements, and reproductive and neurobehavioral functional assessments were also generally carried out. A variety of neurological and neurobehavioral tests were employed. In the majority of rat studies, the potential for long-term cognitive impairment was evaluated using a complex water maze. Juvenile animal studies provided safety information considered relevant to drug use in children and that was included in labeling for 78% of the applications surveyed. The most commonly reported findings in labeling were for neurobehavioral effects, including changes in locomotor activity, auditory startle habituation, and learning and memory. Of the studies described in labeling with neurobehavioral effects, 54% found these effects to be persistent and to provide evidence of developmental neurotoxicity.

Tools in the Design of Therapeutic Drugs for CNS Disorders: An up-to-date Review.

BACKGROUND: The brain is a vital part of the central nervous system (CNS), characterized by the presence of soft tissue in its internal structure which protects itself. Research on design of drugs for CNS disorders is in progress and up to date information is required for further investigation. OBJECTIVE: The present paper is written with the objective to compile all the available data and information on CNS disorders and CNS acting drugs. CNS acting drugs are important to consider because some drugs get ineffective owing to incapability to efficiently deliver and sustain them within the brain for effective treatment. CNS Disorders: The current trend to design therapeutic drugs for CNS disorders focuses on neurotransmitters release and their reuptake, including Parkinson's, Alzheimer's, and other CNS disorders. The disorders associated with CNS are characterized by the progressive loss of gray matter and/or white matter structures. Drugs: CNS stimulants are the class of drugs, producing response to alleviate a particular medical condition. CNS stimulants improve the brain function in patients with schizophrenia and related diseases. CNS stimulants are a class of therapeutic drugs used to treat CNS disorder including the conditions like lack of adrenergic stimulation, symptoms of narcolepsy and neonatal apnea, etc. Apart from drugs, a number of smart tools including Multi-Target Designed Ligands (MTDL) and "predictor" models are contemporarily used to design therapeutic agents for CNS disorders. Mechanism: The majority of CNS stimulants causes stimulation of the traditional "fight or flight" syndrome which is concerned with activation of sympathetic nervous system. These neurotransmitters associated receptors are concerned in drug abuse and addiction withdrawal related phenomenon. CONCLUSION: The present review embarks on detail up-to-date information on CNS stimulant drugs, their mechanism of action, in vivo models for biological evaluations with major emphasis on tools in design of therapeutic drugs for CNS disorders.

Rational Design and Multibiological Profiling of Novel Donepezil-Trolox Hybrids against Alzheimer's Disease, with Cholinergic, Antioxidant, Neuroprotective, and Cognition Enhancing Properties.

A novel series of donepezil-trolox hybrids were designed, synthesized, and evaluated as multifunctional ligands against Alzheimer's disease (AD). Biological assays showed that these derivatives possessed moderate to good inhibitory activities against acetylcholinesterase (AChE) and monoamine oxidase B (MAO-B) as well as remarkable antioxidant effects. The optimal compound 6d exhibited balanced functions with good inhibition against hAChE (IC50 = 0.54 µM) and hMAO-B (IC50 = 4.3 µM), significant antioxidant activity (41.33 µM IC50 by DPPH method, 1.72 and 1.79 trolox equivalent by ABTS and ORAC methods), excellent copper chelation, and Aß1-42 aggregation inhibition effect. Furthermore, cellular tests indicated that 6d has very low toxicity and is capable of combating oxidative toxin (H2O2, rotenone, and oligomycin-A) induced neurotoxicity. Most importantly, oral administration of 6d demonstrated notable improvements on cognition and spatial memory against scopolamine-induced acute memory deficit as well as d-galactose (d-gal) and AlCl3 induced chronic oxidative stress in a mouse model without acute toxicity and hepatotoxicity. In summary, both in vitro and in vivo results suggested that 6d is a valuable candidate for the development of a safe and effective anti-Alzheimer's drug.

Drug discrimination: A versatile tool for characterization of CNS safety pharmacology and potential for drug abuse.

Drug discrimination studies for assessment of psychoactive properties of drugs in safety pharmacology and drug abuse and drug dependence potential evaluation have traditionally been focused on testing novel compounds against standard drugs for which drug abuse has been documented, e.g. opioids, CNS stimulants, cannabinoids etc. (e.g. Swedberg & Giarola, 2015), and results are interpreted such that the extent to which the test drug causes discriminative effects similar to those of the standard training drug, the test drug would be further characterized as a potential drug of abuse. Regulatory guidance for preclinical assessment of abuse liability by the European Medicines Agency (EMA, 2006), the U.S. Food and Drug Administration (FDA, 2010), the International Conference of Harmonization (ICH, 2009), and the Japanese Ministry of Health Education and Welfare (MHLW, 1994) detail that compounds with central nervous system (CNS) activity, whether by design or not, need abuse and dependence liability assessment. Therefore, drugs with peripheral targets and a potential to enter the CNS, as parent or metabolite, are also within scope (see Swedberg, 2013, for a recent review and strategy). Compounds with novel mechanisms of action present a special challenge due to unknown abuse potential, and should be carefully assessed against defined risk criteria. Apart from compounds sharing mechanisms of action with known drugs of abuse, compounds intended for indications currently treated with drugs with potential for abuse and or dependence are also within scope, regardless of mechanism of action. Examples of such compounds are analgesics, anxiolytics, cognition enhancers, appetite control drugs, sleep control drugs and drugs for psychiatric indications. Recent results (Swedberg et al., 2014; Swedberg & Raboisson, 2014; Swedberg, 2015) on the metabotropic glutamate receptor type 5 (mGluR5) antagonists demonstrate that compounds causing hallucinatory effects in humans did not exhibit clear discriminative effects when tested against classical drugs of abuse in drug discrimination studies, and were not self-administered by rats. However, these compounds did cause salient discriminative effects of their own in animals trained to discriminate them from no drug. Therefore, from a safety pharmacology perspective, novel compounds that do not cause discriminative effects similar to classical drugs of abuse, may still cause psychoactive effects in humans and carry the potential to maintain drug abuse, suggesting that proactive investigation of drug abuse potential is warranted (Swedberg, 2013). These and other findings will be discussed, and the application of drug discrimination procedures beyond the typical standard application of testing novel compounds against known and well characterized reference drugs will be addressed.

Preliminary Pharmacological Screening of Some Thiosemicarbazide, s-triazole, and Thiadiazole Derivatives.

Two thiosemicarbazide derivatives 1 and 2, three 2-amino-1,3,4-thiadiazole derivatives 3-5, and three N1- substituted-4-methyl-1,2,4-triazole-5-thione derivatives 6-8 were synthesized and evaluated for their central nervous system effects using rodent behavioral models. With the exception of 6, all compounds were devoid of neurotoxicity and they did not affect the body temperature of mice. New lead structures 1-4 with potential analgesic activity were identified.

Combined therapy with m-TOR-dependent and -independent autophagy inducers causes neurotoxicity in a mouse model of Machado-Joseph disease.

A major pathological hallmark in several neurodegenerative disorders, like polyglutamine disorders (polyQ), including Machado-Joseph disease (MJD), is the formation of protein aggregates. MJD is caused by a CAG repeat expansion in the ATXN3 gene, resulting in an abnormal protein, which is prone to misfolding and forms cytoplasmic and nuclear aggregates within neurons, ultimately inducing neurodegeneration. Treatment of proteinopathies with drugs that up-regulate autophagy has shown promising results in models of polyQ diseases. Temsirolimus (CCI-779) inhibits the mammalian target of rapamycin (m-TOR), while lithium chloride (LiCl) acts by inhibiting inositol monophosphatase, both being able to induce autophagy. We have previously shown that chronic treatment with LiCl (10.4 mg/kg) had limited effects in a transgenic MJD mouse model. Also, others have shown that CCI-779 had mild positive effects in a different mouse model of the disease. It has been suggested that the combination of mTOR-dependent and -independent autophagy inducers could be a more effective therapeutic approach. To further explore this avenue toward therapy, we treated CMVMJD135 transgenic mice with a conjugation of CCI-779 and LiCl, both at concentrations known to induce autophagy and not to be toxic. Surprisingly, this combined treatment proved to be deleterious to both wild-type (wt) and transgenic animals, failing to rescue their neurological symptoms and actually exerting neurotoxic effects. These results highlight the possible dangers of manipulating autophagy in the nervous system and suggest that a better understanding of the potential disruption in the autophagy pathway in MJD is required before successful long-term autophagy modulating therapies can be developed.

Application of Polymeric Nanoparticles for CNS Targeted Zinc Delivery In Vivo.

A dyshomeostasis of zinc ions has been reported for many psychiatric and neurodegenerative disorders including schizophrenia, attention deficit hyperactivity disorder, depression, autism, Parkinson's and Alzheimer's disease. Furthermore, alterations in zinc-levels have been associated with seizures and traumatic brain injury. Thus, altering zinclevels within the brain is emerging as a new target for the prevention and treatment of psychiatric and neurological diseases. However, given the restriction of zinc uptake into the brain by the blood-brain barrier, methods for controlled regulation and manipulation of zinc concentrations within the brain are rare. Here, we performed in vivo studies investigating the possibility of brain targeted zinc delivery using zinc-loaded nanoparticles which are able to cross the blood-brain barrier. After injecting these nanoparticles, we analyzed the regional and time-dependent distribution of zinc and nanoparticles within the brain. Moreover, we evaluated whether the presence of zinc-loaded nanoparticles alters the expression of zinc sensitive genes and proteins such as metallothioneins and zinc transporters and quantified possible toxic effects. Our results show that zinc loaded g7 nanoparticles offer a promising approach as a novel non - invasive method to selectively enrich zinc in the brain within a small amount of time.

Alkaloids from piper: a review of its phytochemistry and pharmacology.

OBJECTIVE: Piper has been used for long timelike condiment and food, but also in traditional medicine around of the world. This work resumes the available and up to date work done on members of the Piperaceae family and their uses for therapeutic purposes. METHODS: Information on Piper genus was gathered via internet using scientific databases such as Scirus, Google Scholar, CAB-abstracts, MedlinePlus, Pubmed, SciFinder, Scopus and Web of Science. RESULTS: The largeleafed perennial plant Piper is used for its spicy aromatic scent and flavor. It has an important presence in the cuisine of different cultures. Another quality of these plants is their known medicinal properties. It has been used as emollient, antirheumatic, diuretic, stimulant, abortifacient, anti-inflammatory, antibacterial, antifungal and antidermatophytic. A survey of the literature shows that the genus Piper is mainly known for its alkaloids with cytotoxic, chemopreventive, antimetastatic and antitumor properties in several types of cancer. Studies of its alkaloids highlight the existence of various potential leads to develop new anti-cancer agents. Modern pharmacology studies have demonstrated that its crude extracts and active compounds possess wide pharmacological activities, especially asantioxidant, anti-depressive, hepatoprotective, antimicrobial, anti-obesity, neuropharmacological, to treat cognitive disorders, anti-hyperlipidemic, anti-feedant, cardioactive, immuno-enhancing, and anti-inflamatory. All this evidence supporting its traditional uses. AIM OF THE REVIEW: This review summarizes the up-to-date and comprehensive information concerning the botany, traditional use, phytochemistry and pharmacology of Piper together with its toxicology, and discusses the possible trend and scope for further research on Piper in the future.

Preclinical evaluation of Trichilia catigua extracts on the central nervous system of mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Trichilia catigua preparations have been popularly used in Brazil as a tonic for the treatment of fatigue, stress, impotence, and deficiency of memory. The aim of the present study was to investigate the possible antidepressant, anxiolytic, motor and cognitive effects of the crude extract (CE) or ethyl-acetate fraction (EAF) of Trichilia catigua. Analyses of the total phenolics and total tannins content, as well as the in vitro antioxidant activity of CE and EAF were also performed. MATERIALS AND METHODS: CE (200-800 mg/kg) and EAF (100-400mg/kg) were orally administered to mice and 1h later the behavioral tests were performed. The free radical scavenging activity was measured by using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) method. RESULTS: Single administration of CE (200-400 mg/kg) or EAF (100-400 mg/kg) did not change the behavior of the animals submitted to the elevated plus maze or their locomotor activity in the open field test. An antidepressant-like effect was detected with EAF (400 mg/kg) after acute administration. Both CE (800 mg/kg) and EAF (200 and 400 mg/kg), improve memory in mice as measured by an increased latency in the step-down inhibitory avoidance test. The EAF presented higher total phenolics and total tannins as compared to CE as well as it exhibited the best antioxidant activity. CONCLUSIONS: The present results showed an in vitro antioxidant activity for EAF and suggested that it may be useful for cognitive improvement. It is possible that both functional and chemical activities are related.

Use of high content image analysis to detect chemical-induced changes in synaptogenesis in vitro.

Synaptogenesis is a critical process in nervous system development whereby neurons establish specialized contact sites which facilitate neurotransmission. Early life exposure to chemicals can result in persistent deficits in nervous system function at later life stages. These effects are often the result of abnormal development of synapses. Given the large number of chemicals in commerce with unknown potential to result in developmental neurotoxicity (DNT), the need exists for assays that can efficiently characterize and quantify chemical effects on brain development including synaptogenesis. The present study describes the application of automated high content image analysis (HCA) technology for examining synapse formation in rodent primary mixed cortical cultures. During the first 15 days in vitro (DIV) cortical neurons developed a network of polarized neurites (i.e., axons and dendrites) and expression of the pre-synaptic protein synapsin increased over time. The localization of punctate synapsin protein in close apposition to dendrites also increased, indicating an increase in synapse formation. Results demonstrated that: (1) punctate synapsin protein with a spatial orientation consistent with synaptic contact sites could be selectively measured, (2) the critical period for synaptogenesis in cortical cultures was consistent with previous reports, (3) chemicals known to inhibit synapse formation decreased automated measurements of synapse number and (4) parallel evaluation of neuron density, dendrite length and synapse number could distinguish frank cytotoxicity from specific effects on synapse formation or neuronal morphology. Collectively, these data demonstrate that automated image analysis can be used to efficiently assess synapse formation in primary cultures and that the resultant data is comparable to results obtained using lower throughput methods.

Screening for phospholipidosis induced by central nervous drugs: comparing the predictivity of an in vitro assay to high throughput in silico assays.

Drug-induced phospholipidosis is a side effect for which drug candidates can be screened in the drug discovery phase. The numerous in silico models that have been developed as a first line of screening are based on the characteristic physicochemical properties of phospholipidosis-inducing drugs, e.g. high logP and pK(b) values. However, applying these models on a predominantly high lipophilic, basic CNS chemistry results in a high false positive rate and consequently in a wrong classification of a large number of valuable drug candidates. Here, we tested 33 CNS-compounds (24 in vivo negative and 9 in vivo positive phospholipidosis-inducers) in our in house developed in vitro phospholipidosis screening assay (Mesens et al., 2009) and compared its predictivity with the outcome of three different, well established in silico prediction models. Our in vitro assay demonstrates an increased specificity of 79% over the in silico models (29%). Moreover, by considering the proposed plasma concentration at the efficacious dose we can show a clear correlation between the in vitro and in vivo occurrence of phospholipidosis, improving the specificity of prediction to 96%. Through its high predictive value, the in vitro low throughput assay is thus preferred above high throughput in silico assays, characterized by a high false positive rate.

Caspase-3 activation in the guinea pig cochlea exposed to salicylate.

In the current study, we explored whether chronic salicylate exposure could induce apoptosis in outer hair cells (OHCs) and spiral ganglion neurons (SGNs) of the cochlea. Guinea pig received sodium salicylate (400 mg/kg/d) or saline vehicle for 10 consecutive days. Programmed cell death (PCD) executioner was evaluated with immunohistochemistry detection of activated caspase-3. Apoptosis was examined with a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method. Repeated salicylate administration activated caspase-3 and caused apoptosis in OHCs and SGNs (p<0.01 vs. saline control for both measures and in both cell types). Cell counting showed a significant loss in OHCs (p<0.01 vs. saline control), but not in inner hair cells (IHCs). Transmission electron microscopy (TEM) revealed chromatin condensation and nucleus margination in salicylate-treated cochlea. Scanning electron microscopy (SEM) demonstrated stereociliary bundles breakdown and fusion at the apical of OHCs, villous matter was discovered to attach on the surface of SGNs. These findings suggest that long-term administration of high-dose salicylate can activate caspase-3 pathway to induce OHC and SGN apoptosis.

Alpha-ketoisocaproic acid and leucine provoke mitochondrial bioenergetic dysfunction in rat brain.

Patients affected by maple syrup urine disease (MSUD) present severe neurological symptoms and brain abnormalities, whose pathophysiology is poorly known. In the present study we investigated the in vitro effects of leucine (Leu), alpha-ketoisocaproic acid (KIC) and alpha-hydroxyisovaleric acid (HIV), respectively, the branched-chain amino, keto and hydroxy acids that most accumulate in MSUD, on brain bioenergetic homeostasis, evaluating respiratory parameters obtained by oxygen consumption, membrane potential (Psim), NAD(P)H content, swelling and citric acid cycle enzyme activities in mitochondrial preparations from rat forebrain using glutamate plus malate, succinate or alpha-ketoglutarate as respiratory substrates. KIC increased state 4 and decreased the respiratory control ratio with all substrates, in contrast with Leu and HIV. Furthermore, KIC and Leu, but not HIV, decreased state 3 using alpha-ketoglutarate. A KIC-induced selective inhibition of alpha-ketoglutarate dehydrogenase activity was also verified, with no alteration of the other citric acid cycle activities. The ADP/O ratio and the mitochondrial NAD(P)H levels were also reduced by KIC using glutamate/malate and alpha-ketoglutarate. In addition, KIC caused a reduction in the Psim when alpha-ketoglutarate was the substrate. Finally, KIC was not able to induce mitochondrial swelling. The present data indicate that KIC acts as an uncoupler of oxidative phosphorylation and as a metabolic inhibitor possibly through its inhibitory effect on alpha-ketoglutarate dehydrogenase activity, while Leu acts as a metabolic inhibitor. It is suggested that impairment of mitochondrial homeostasis caused by the major metabolites accumulating in MSUD may be involved in the neuropathology of this disease.

Moving beyond rules: the development of a central nervous system multiparameter optimization (CNS MPO) approach to enable alignment of druglike properties.

The interplay among commonly used physicochemical properties in drug design was examined and utilized to create a prospective design tool focused on the alignment of key druglike attributes. Using a set of six physicochemical parameters ((a) lipophilicity, calculated partition coefficient (ClogP); (b) calculated distribution coefficient at pH = 7.4 (ClogD); (c) molecular weight (MW); (d) topological polar surface area (TPSA); (e) number of hydrogen bond donors (HBD); (f) most basic center (pK(a))), a druglikeness central nervous system multiparameter optimization (CNS MPO) algorithm was built and applied to a set of marketed CNS drugs (N = 119) and Pfizer CNS candidates (N = 108), as well as to a large diversity set of Pfizer proprietary compounds (N = 11 303). The novel CNS MPO algorithm showed that 74% of marketed CNS drugs displayed a high CNS MPO score (MPO desirability score ≥ 4, using a scale of 0-6), in comparison to 60% of the Pfizer CNS candidates. This analysis suggests that this algorithm could potentially be used to identify compounds with a higher probability of successfully testing hypotheses in the clinic. In addition, a relationship between an increasing CNS MPO score and alignment of key in vitro attributes of drug discovery (favorable permeability, P-glycoprotein (P-gp) efflux, metabolic stability, and safety) was seen in the marketed CNS drug set, the Pfizer candidate set, and the Pfizer proprietary diversity set. The CNS MPO scoring function offers advantages over hard cutoffs or utilization of single parameters to optimize structure-activity relationships (SAR) by expanding medicinal chemistry design space through a holistic assessment approach. Based on six physicochemical properties commonly used by medicinal chemists, the CNS MPO function may be used prospectively at the design stage to accelerate the identification of compounds with increased probability of success.

Co-exposure to arsenic and fluoride on oxidative stress, glutathione linked enzymes, biogenic amines and DNA damage in mouse brain.

We studied the effects of combined exposure to arsenic and fluoride on (i) brain biogenic amines, oxidative stress and its correlation with glutathione and linked enzymes; (ii) alterations in the structural integrity of DNA; and (iii) brain and blood arsenic and fluoride levels. Efficacy of alpha-tocopherol in reducing these changes was also determined. Male mice were exposed to sodium meta arsenite (50 ppm) and sodium fluoride (50 ppm) individually and in combination for ten weeks. Animals were given vitamin E supplementation (5 mg/kg, i.m., alternate days) throughout the experiment. Exposure to arsenic and fluoride significantly decreased the levels of brain biogenic amines. However; acetyl cholinesterase (AChE) and monoamine oxidase (MAO) activities showed an increase on fluoride exposure. There was also an increase in reactive oxygen species, thiobarbituric acid reactive species level, glutathione S-transferase and glutathione peroxidase activities and decreased superoxide dismutase activity, GSH:GSSG ratio, glucose 6-phosphate dehydrogenase activity. Combined exposure to these toxicants produced more pronounced effects on AChE, MAO, SOD and catalase activities. Infrared spectra showed less toxicity during combined exposure as the characteristic peaks of cytosine and alpha-helical structure of DNA were observed in normal and arsenic plus fluoride-exposed animals. Vitamin E reduced brain fluoride level and tissue oxidative stress but had no effect on arsenic. Combined exposure to arsenic and fluoride does not necessarily lead to more pronounced toxicity and interestingly exhibit some antagonistic effects. Vitamin E supplementation may be of added value in reverting some of the toxic effects.

Prenatal cocaine reduces AMPA receptor synaptic expression through hyperphosphorylation of the synaptic anchoring protein GRIP.

Prenatal cocaine exposure produces sustained neurobehavioral and brain synaptic changes closely resembling those of animals with defective AMPA receptors (AMPARs). We hypothesized that prenatal cocaine exposure attenuates AMPAR signaling by interfering with AMPAR synaptic targeting. AMPAR function is governed by receptor cycling on and off the synaptic membrane through its interaction with glutamate receptor-interacting protein (GRIP), a PDZ domain protein that is regulated by reversible phosphorylation. Our results show that prenatal cocaine exposure markedly reduces AMPAR synaptic targeting and attenuates AMPAR-mediated synaptic long-term depression in the frontal cortex of 21-d-old rats. This cocaine effect is the result of reduced GRIP-AMPAR interaction caused by persistent phosphorylation of GRIP by protein kinase C (PKC) and Src tyrosine kinase. These data support the restoration of AMPAR activation via suppressing excessive PKC-mediated GRIP phosphorylation as a novel therapeutic approach to treat the neurobehavioral consequences of prenatal cocaine.

Pharmacological actions of Thespesia populnea relevant to Alzheimer's disease.

Thespesia populnea (Malvaceae) is a large tree found in the tropical regions and coastal forests of India. Various parts of T. populnea are found to possess useful medicinal properties, such as antifertility, antibacterial, anti-inflammatory, antioxidant, purgative and hepatoprotective activity. The present study was undertaken to investigate the effects of T. populnea bark on cognitive functions, total cholesterol levels and cholinesterase activity in mice. A total of 312 mice divided into 52 different groups were employed in the present investigation. The ethanolic extract of T. populnea (TPE) was administered orally in three doses (100, 200 and 400 mg/kg) for 7 successive days to different groups of young and aged mice. The learning and memory parameters were assessed using elevated plus maze and passive avoidance apparatus. TPE (200 and 400 mg/kg, p.o.) showed significant improvement in memory of young and aged mice. TPE also reversed the amnesia induced by scopolamine (0.4 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.). Furthermore, TPE reduced significantly the central (brain) cholinesterase activity in mice. TPE exhibited a remarkable cholesterol lowering property comparable to simvastatin (a standard drug) in the present study. Furthermore, we observed that, T. populnea bark possessed a powerful memory enhancing activity in mice. Since diminished cholinergic transmission and increased cholesterol levels appear to be responsible for development of amyloid plaques and dementia in Alzheimer patients, TPE may prove to be a useful medicine on account of its multifarious beneficial effects, such as memory improving property, cholesterol lowering, anticholinesterase and anti-inflammatory activity. Therefore, T. populnea bark appears to be a promising candidate for improving memory and it would be worthwhile to explore the potential of this plant in the management of Alzheimer patients.

Spectrum of effects detected in the rat functional observational battery following oral administration of non-CNS targeted compounds.

INTRODUCTION: The Functional Observational Battery (FOB) is a systematic evaluation of nervous system function in the rat, comprising more than 30 parameters across autonomic, neuromuscular, sensorimotor and behavioural domains. We have collated FOB outcomes from 50 compounds that were not targeted at CNS disorders, and would therefore be anticipated to have relatively few CNS side-effects, for evaluation of the FOB as part of the safety pharmacology 'core battery'. METHODS: Male Han Wistar rats (200-300 g) were used, with n=6 per treatment group. Each compound was tested acutely at 3 dose levels (oral route), from the therapeutic dose up to either 100 times this dose or to the maximal tolerated dose (MTD). A vehicle control group was included in each study. RESULTS: Effects were detected in the FOB for 94% of compounds tested. The commonest effects were weight loss/decreased body weight gain overnight post-dose (46% of compounds), and changes in core temperature (36%). Dose-related effects were observed with 62% of compounds; the commonest was decreased body weight gain (32%), followed by effects on tail flick latency (14%), landing foot splay (12%), decreased rectal temperature (10%), time to exit the centre circle in the open field (10%), diarrhoea/loose faeces (8%), respiratory effects (4%), grasping reflex (4%) and supported rears in the open field (4%). Remaining parameters were affected by < or =2% of compounds. DISCUSSION: The value of doing the FOB as part of the safety pharmacology 'core battery' is emphasised by the fact that, even for non-CNS targeted compounds, the majority affected at least one of the parameters in the FOB. These data may also help to anticipate the most frequently required 'follow-up' studies.