Comparative Neuropharmacology and Pharmacokinetics of Methamphetamine and Its Thiophene Analog Methiopropamine in Rodents

Methiopropamine is a novel psychoactive substance (NPS) that is associated with several cases of clinical toxicity, yet little information is available regarding its neuropharmacological properties. Here, we employed in vitro and in vivo methods to compare the pharmacokinetics and neurobiological effects of methiopropamine and its structural analog methamphetamine. Methiopropamine was rapidly distributed to the blood and brain after injection in C57BL/6 mice, with a pharmacokinetic profile similar to that of methamphetamine. Methiopropamine induced psychomotor activity, but higher doses were needed (E_max 12.5 mg/kg; i.p.) compared to methamphetamine (E_max 3.75 mg/kg; i.p.). A steep increase in locomotor activity was seen after a modest increase in the methiopropamine dose from 10 to 12.5 mg/kg, suggesting that a small increase in dosage may engender unexpectedly strong effects and heighten the risk of unintended overdose in NPS users. In vitro studies revealed that methiopropamine mediates its effects through inhibition of norepinephrine and dopamine uptake into presynaptic nerve terminals (IC₅₀ = 0.47 and 0.74 µM, respectively), while the plasmalemmal serotonin uptake and vesicular uptake are affected only at high concentrations (IC₅₀ > 25 µM). In summary, methiopropamine closely resembles methamphetamine with regard to its pharmacokinetics, pharmacodynamic effects and mechanism of action, with a potency that is approximately five times lower than that of methamphetamine.

Neuropharmacology of attention

Early philosophers and psychologists defined and began to describe attention. Beginning in the 1950's, numerous models of attention were developed. This corresponded with an increased understanding of pharmacological approaches to manipulate neurotransmitter systems. The present review focuses on the knowledge that has been gained about these neurotransmitter systems with respect to attentional processing, with emphasis on the functions mediated within the medial prefrontal cortex. Additionally, the use of pharmacotherapies to treat psychiatric conditions characterized by attentional dysfunction are discussed. Future directions include developing a more comprehensive understanding of the neural mechanisms underlying attentional processing and novel pharmacotherapeutic targets for conditions characterized by aberrant attentional processing.

Utilizing resources of neuropsychopharmacology to address the opioid overdose crisis

BACKGROUND

North America is facing a severe public health crisis in the form of excessive numbers of deaths due to overdose from self-administration of opioids by individuals who are dependent on these substances.

AIMS

There are many factors that must be addressed in order to gain control over this tragedy. Of particular relevance to neuropsychopharmacology is the fact that the problem is due in part to misuse of pharmaceuticals and especially the illicit production of the powerful synthetic opioids, fentanyl, and carfentanil.

METHOD

The development and adoption of appropriate pharmacotherapies are of critical importance. We discuss specific options to deal effectively with both withdrawal from opioid dependence and substitution of clinically approved drugs in place of illicit substances.

CONCLUSION

Hopefully, this crisis will reinvigorate both basic and clinical neuropsychopharmacological research leading to the develop new and more effective options for dealing with the many and varied elements of the current opioid crisis as described in the present commentary.

Neuroimmune Pharmacology, 2nd Edition - A Perspective

It has been almost nine years since the 1st edition of Neuroimmune Pharmacology was published on May 23rd, 2008. The 2nd edition of Neuroimmune Pharmacology by Ikezu and Gendelman (Editors) with Przedborski, Masliah and Cosentino (Associate Editors) manages to fulfill two separate missions: to provide comprehensive, but highly topical access to a rapidly evolving field and to serve as a standalone reference for scientists and clinicians in need of guidance regarding questions pertinent to neuroimmune pharmacology. Doing a PubMed search on the terms neuroimmune and pharmacology yields 1090 publications, with a first publication by Dougherty and Dafny, published in the Journal of Neuroscience Research in 1988, entitled "Neuroimmune intercommunication, central opioids, and the immune response to bacterial endotoxin." Since 2000, there have been 979 publications using these search terms, with 137 published since the beginning of 2016. The obvious conclusion to be drawn is that this is a burgeoning field that represents the cusp between our understanding of relationships between the immune and nervous systems and how we might treat disease with pharmacologic approaches when normal homeostatic mechanisms go awry.

The Neuropharmacology of Cluster Headache and other Trigeminal Autonomic Cephalalgias

Trigeminal autonomic cephalalgias (TACs) are a group of primary headaches including cluster headache (CH), paroxysmal hemicrania (PH) and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT). Another form, hemicrania continua (HC), is also included this group due to its clinical and pathophysiological similarities. CH is the most common of these syndromes, the others being infrequent in the general population. The pathophysiology of the TACs has been partly elucidated by a number of recent neuroimaging studies, which implicate brain regions associated with nociception (pain matrix). In addition, the hypothalamic activation observed in the course of TAC attacks and the observed efficacy of hypothalamic neurostimulation in CH patients suggest that the hypothalamus is another key structure. Hypothalamic activation may indeed be involved in attack initiation, but it may also lead to a condition of central facilitation underlying the recurrence of pain episodes. The TACs share many pathophysiological features, but are characterised by differences in attack duration and frequency, and to some extent treatment response. Although alternative strategies for the TACs, especially CH, are now emerging (such as neurostimulation techniques), this review focuses on the available pharmacological treatments complying with the most recent guidelines. We discuss the clinical efficacy and tolerability of the currently used drugs. Due to the low frequency of most TACs, few randomised controlled trials have been conducted. The therapies of choice in CH continue to be the triptans and oxygen for acute treatment, and verapamil and lithium for prevention, but promising results have recently been obtained with novel modes of administration of the triptans and other agents, and several other treatments are currently under study. Indomethacin is extremely effective in PH and HC, while antiepileptic drugs (especially lamotrigine) appear to be increasingly useful in SUNCT. We highlight the need for appropriate studies investigating treatments for these rare, but lifelong and disabling conditions.

Data collection and analysis strategies for phMRI

Although functional MRI traditionally has been applied mainly to study changes in task-induced brain function, evolving acquisition methodologies and improved knowledge of signal mechanisms have increased the utility of this method for studying responses to pharmacological stimuli, a technique often dubbed "phMRI". The proliferation of higher magnetic field strengths and the use of exogenous contrast agent have boosted detection power, a critical factor for successful phMRI due to the restricted ability to average multiple stimuli within subjects. Receptor-based models of neurovascular coupling, including explicit pharmacological models incorporating receptor densities and affinities and data-driven models that incorporate weak biophysical constraints, have demonstrated compelling descriptions of phMRI signal induced by dopaminergic stimuli. This report describes phMRI acquisition and analysis methodologies, with an emphasis on data-driven analyses. As an example application, statistically efficient data-driven regressors were used to describe the biphasic response to the mu-opioid agonist remifentanil, and antagonism using dopaminergic and GABAergic ligands revealed modulation of the mesolimbic pathway. Results illustrate the power of phMRI as well as our incomplete understanding of mechanisms underlying the signal. Future directions are discussed for phMRI acquisitions in human studies, for evolving analysis methodologies, and for interpretative studies using the new generation of simultaneous PET/MRI scanners. This article is part of the Special Issue Section entitled 'Neuroimaging in Neuropharmacology'.

Treating prolonged symptoms of mild traumatic brain injury: neuropharmacology

The clinical presentation of concussion can vary widely as patients experience any number of symptoms including headache, dizziness, cognitive symptoms of difficulty with concentration and memory, sleep dysregulation, and mood disturbances. The variability in clinical presentation underscores the importance of thorough history-taking to clearly understand the clinical picture and to allow individualization of the treatment plan. Most postconcussive symptoms are transient in nature and respond to conservative measures, including education of the patient and their caregivers. For those individuals whose symptoms persist or significantly impair quality of life, pharmacologic intervention may be warranted. Though few studies have investigated the use of pharmacology for treatment of postconcussion syndrome specifically, targeted treatment of medications known to improve selected symptoms can be considered.

From basic to clinical neuropharmacology: targetophilia or pharmacodynamics?

Historically, much drug discovery and development in psychopharmacology tended to be empirical. However, over the last 20 years it has primarily been target oriented, with synthesis and selection of compounds designed to act at a specific neurochemical site. Such compounds are then examined in functional animal models of disease. There is little evidence that this approach (which we call 'targetophilia') has enhanced the discovery process and some indications that it may have retarded it. A major problem is the weakness of many animal models in mimicking the disease and the lack of appropriate biochemical markers of drug action in animals and patients. In this review we argue that preclinical studies should be conducted as if they were clinical studies in design, analysis, and reporting, and that clinical pharmacologists should be involved at the earliest stages, to help ensure that animal models reflect as closely as possible the clinical disease. In addition, their familiarity with pharmacokinetic-pharmacodynamic integration (PK-PD) would help ensure that appropriate dosing and drug measurement techniques are applied to the discovery process, thereby producing results with relevance to therapeutics. Better integration of experimental and clinical pharmacologists early in the discovery process would allow observations in animals and patients to be quickly exchanged between the two disciplines. This non-linear approach to discovery used to be the way research proceeded, and it resulted in productivity that has never been bettered. It also follows that occasionally 'look-see' studies, a proven technique for drug discovery, deserve to be reintroduced.

Evaluation of n-hexane extract of Viola betonicifolia for its neuropharmacological properties

Viola betonicifolia (whole plant) has been used as a sedative and in various nervous disorders in Pakistani traditional medicines. The n-hexane extract of the whole plant of V. betonicifolia (HEVB) was investigated for neuropharmacological properties such as anxiolytic, muscle relaxant, sleep induction, antidepressant and sedative to ascertain its folk use. Anxiolytic activity was tested using the staircase test, while the muscle relaxing property of the extract was tested in various muscle relaxant paradigms, i.e. chimney test, traction test, rota rod and inclined plane. In anxiolytic and muscle relaxant tests, HEVB (0.3, 0.4 and 0.5 g/kg, i.p.), diazepam (1 mg/kg, i.p.) or distilled water (10 ml/kg i.p.) were administered 30, 60 and 90 min before performing the tests in mice. HEVB was also screened for a sleep-inducing effect. The antidepressant activity was determined by using the forced swimming test (FST), while line crossing in a special box was used for locomotor activity. HEVB showed a significant (P < 0.05) dose-dependent anxiolytic action in the staircase test. In muscle relaxant paradigms, a dose-dependent muscle relaxation was observed. For the phenobarbitone sleep induction test, HEVB notably (P < 0.05) reduced the latency time and increased the total sleeping duration. However, HEVB was devoid of any antidepressant activity, while the movements of mice were reduced significantly (P < 0.05) in locomotor activity. The results suggest that HEVB has anxiolytic, muscle relaxant, sleep-inducing (sedative) activity and, thus, provides pharmacological justification for the use of this plant as a sedative and for the relief of various nervous disorders.

From benzodiazepines to peripheral and brain steroid biosynthesis

From the biochemistry of testicular and adrenal steroids to the mysteries of brain steroid biosynthesis and from pharmacy and pharmacology to neuropharmacology and neurosciences were two transitions in my scientific career where Erminio (Mimo) Costa played a catalytic role. A review of the years and findings that contributed in our understanding of the link between benzodiazepines and neurosteroid biosynthesis that established the pharmacology of neurosteroidogenesis is a testimony to Dr. Costa's will to push the borders of knowledge that inspired us to challenge existing notions and paradigms.

The roles of dopamine and serotonin in decision making: evidence from pharmacological experiments in humans

Neurophysiological experiments in primates, alongside neuropsychological and functional magnetic resonance investigations in humans, have significantly enhanced our understanding of the neural architecture of decision making. In this review, I consider the more limited database of experiments that have investigated how dopamine and serotonin activity influences the choices of human adults. These include those experiments that have involved the administration of drugs to healthy controls, experiments that have tested genotypic influences upon dopamine and serotonin function, and, finally, some of those experiments that have examined the effects of drugs on the decision making of clinical samples. Pharmacological experiments in humans are few in number and face considerable methodological challenges in terms of drug specificity, uncertainties about pre- vs post-synaptic modes of action, and interactions with baseline cognitive performance. However, the available data are broadly consistent with current computational models of dopamine function in decision making and highlight the dissociable roles of dopamine receptor systems in the learning about outcomes that underpins value-based decision making. Moreover, genotypic influences on (interacting) prefrontal and striatal dopamine activity are associated with changes in choice behavior that might be relevant to understanding exploratory behaviors and vulnerability to addictive disorders. Manipulations of serotonin in laboratory tests of decision making in human participants have provided less consistent results, but the information gathered to date indicates a role for serotonin in learning about bad decision outcomes, non-normative aspects of risk-seeking behavior, and social choices involving affiliation and notions of fairness. Finally, I suggest that the role played by serotonin in the regulation of cognitive biases, and representation of context in learning, point toward a role in the cortically mediated cognitive appraisal of reinforcers when selecting between actions, potentially accounting for its influence upon the processing salient aversive outcomes and social choice.

Understanding the effects of stimulant medications on cognition in individuals with attention-deficit hyperactivity disorder: a decade of progress

The use of stimulant drugs for the treatment of children with attention-deficit hyperactivity disorder (ADHD) is one of the most widespread pharmacological interventions in child psychiatry and behavioral pediatrics. This treatment is well grounded on controlled studies showing efficacy of low oral doses of methylphenidate and amphetamine in reducing the behavioral symptoms of the disorder as reported by parents and teachers, both for the cognitive (inattention and impulsivity) and non-cognitive (hyperactivity) domains. Our main aim is to review the objectively measured cognitive effects that accompany the subjectively assessed clinical responses to stimulant medications. Recently, methods from the cognitive neurosciences have been used to provide information about brain processes that underlie the cognitive deficits of ADHD and the cognitive effects of stimulant medications. We will review some key findings from the recent literature, and then offer interpretations of the progress that has been made over the past decade in understanding the cognitive effects of stimulant medication on individuals with ADHD.

European College of Neuropsychopharmacology (ECNP) - 23rd Congress

The 23rd Congress of the European College of Neuropsychopharmacology (ECNP), held in Amsterdam, included topics covering new therapeutic developments in the field of neuropsychopharmacology. This conference report highlights selected presentations on potential psychotropic drug targets, the relationship between psychiatric disorders and pain, treatments for depression and anxiety disorders, the role of glucocorticoid receptors in memory consolidation, and the use of anticonvulsants in impulse disorders.

Method development studies for repeatedly measuring anxiolytic drug effects in healthy humans

Human experimental models for anxiety may serve as translational tools for translating preclinical psychopharmacological investigations into human studies. For the evaluation of drugs of which pharmacokinetics and pharmacodynamics are unidentified, repeating measurements after drug administration is necessary for characterising the time course of drug effects. In experiment 1, a threat-of-shock paradigm and adaptations of the Trier mental arithmetic test and the Stroop colour naming test were repeated four times within a day to evaluate whether anxiety responses to this test battery remain stable after repeated testing. This procedure was repeated on 4 days in a second experiment to evaluate suitability of the paradigm for a crossover design with multiple sessions. Results indicate no reductions or changes in fear potentiated startle, the main outcome measure for the threat paradigm, over test sessions or days. Skin conductance responses and subjective ratings under threat-of-shock showed significant fluctuations but also no systematic decline over time. Finally, the threat paradigm and Stroop test resulted in small increases in reported state anxiety while mental arithmetic produced larger effects that diminished after the first test day. It is concluded that especially the startle paradigm could be a useful new instrument for screening new anxiolytic drugs.

Endogenous nociceptin/orphanin FQ (N/OFQ) contributes to haloperidol-induced changes of nigral amino acid transmission and parkinsonism: a combined microdialysis and behavioral study in naïve and nociceptin/orphanin FQ receptor knockout mice

The contribution of endogenous nociceptin/orphanin FQ (N/OFQ) to neuroleptic-induced parkinsonism has been evaluated in haloperidol-treated mice. Pharmacological blockade of N/OFQ receptors (NOP) via systemic administration of 1-[(3R,4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidyl]-3-ethyl-1,3-dihydro-2H benzimidazol-2-one (J-113397, 0.01-10 mg/kg i.p.) or central injection of [Nphe(1),Arg(14),Lys(15)]N/OFQ-NH(2) (UFP-101, 10 nmol i.c.v.) attenuated (0.8 mg/kg) haloperidol-induced motor deficits as evaluated by a battery of behavioral tests providing complementary information on motor parameters: the bar, drag and rotarod tests. A combined neurochemical and behavioral approach was then used to investigate whether the substantia nigra reticulata could be involved in antiakinetic actions of J-113397. Microdialysis combined to the bar test revealed that haloperidol (0.3 and 0.8 mg/kg i.p.) caused a dose-dependent and prolonged elevation of immobility time (i.e. akinesia) which was associated with an increase in nigral glutamate and a reduction in GABA release. Conversely, J-113397 (1 mg/kg) alone reduced glutamate and elevated nigral GABA release, and when challenged against haloperidol, counteracted its behavioral and neurochemical effects. Microdialysis coupled to behavioral testing also demonstrated that NOP receptor knockout mice were resistant to haloperidol (0.3 mg/kg) compared to wild-type mice, lack of response being associated with a reversal of glutamate release facilitation into inhibition and no change in nigral GABA release. This study provides pharmacological and genetic evidence that endogenous N/OFQ contributes to haloperidol-induced akinesia and changes of amino acid transmission in mice. Moreover, it confirms the view that NOP receptor antagonists are capable of reversing akinesia across species and genotypes and may prove effective in relieving neuroleptic-induced parkinsonism.

Spontaneously hypertensive rat neuroanatomy: applications to pharmacological research

Spontaneously hypertensive rats (SHR), which are normotensive at birth and develop sustained hypertension between 3 and 6 months of age, are the model most extensively investigated for evaluating hypertensive brain damage and its treatment. The time-dependent rise of arterial blood pressure and the occurrence of brain atrophy, loss of nerve cells and glial reaction are shared to some extent with what occurs human hypertensive brain. SHR, therefore, can represent a reasonable model of hypertension-related brain damage. Our main studies on cerebrovascular and brain microanatomical changes occurring in SHR and their sensitivity to pharmacological interventions are summarized.

The neuropharmacology of relapse to food seeking: methodology, main findings, and comparison with relapse to drug seeking

Relapse to old, unhealthy eating habits is a major problem in human dietary treatments. The mechanisms underlying this relapse are unknown. Surprisingly, until recently this clinical problem has not been systematically studied in animal models. Here, we review results from recent studies in which a reinstatement model (commonly used to study relapse to abused drugs) was employed to characterize the effect of pharmacological agents on relapse to food seeking induced by either food priming (non-contingent exposure to small amounts of food), cues previously associated with food, or injections of the pharmacological stressor yohimbine. We also address methodological issues related to the use of the reinstatement model to study relapse to food seeking, similarities and differences in mechanisms underlying reinstatement of food seeking versus drug seeking, and the degree to which the reinstatement procedure provides a suitable model for studying relapse in humans. We conclude by discussing implications for medication development and future research. We offer three tentative conclusions: (1)The neuronal mechanisms of food-priming- and cue-induced reinstatement are likely different from those of reinstatement induced by the pharmacological stressor yohimbine. (2)The neuronal mechanisms of reinstatement of food seeking are possibly different from those of ongoing food-reinforced operant responding. (3)The neuronal mechanisms underlying reinstatement of food seeking overlap to some degree with those of reinstatement of drug seeking.

Targeted disruption of cocaine-activated nucleus accumbens neurons prevents context-specific sensitization

Learned associations between effects of abused drugs and the drug administration environment are important in drug addiction. Histochemical and electrophysiological studies suggest that these associations are encoded in sparsely distributed nucleus accumbens neurons that are selectively activated by drugs and drug-associated cues. Although correlations have been observed between nucleus accumbens neuronal activity and responsivity to drugs and drug cues, no technique exists for selectively manipulating these activated neurons and establishing their causal role in behavioral effects of drugs and drug cues. Here we describe a new approach, which we term the 'Daun02 inactivation method', that selectively inactivates a minority of neurons previously activated by cocaine in an environment repeatedly paired with cocaine to demonstrate a causal role for these activated neurons in context-specific cocaine-induced psychomotor sensitization in rats. This method provides a new tool for studying the causal roles of selectively activated neurons in behavioral effects of drugs and drug cues and in other learned behaviors.

Neuropharmacological studies on Wedelia calendulacea Less stem extract

The neuropharmacological activities of the methanolic and aqueous extract of Wedelia calendulacea stem were screened in rats and mice. The extracts effect on pentobarbital-induced sleeping time, pentylenetetrazole- and styrychnine-induced seizure, spontaneous motor activity, exploratory behaviour, and rota-rod performance (motor coordination) were evaluated. The methanolic extract (20 and 50 mg/kg, i.p.) and aqueous extract (200 and 500 mg/kg, i.p.) produced a significant (p<0.001) prolongation of pentobarbital-induced sleeping time, and reduced the SMA and exploratory behaviour. The extract prolonged onset of the phases of seizure activity but did not protect mice against lethality induced by pentylenetetrazole and strychnine. It also failed to affect the motor coordination test. These results suggest that the extract contained an agent with neuropharmacological activity that may be sedative in nature. In addition, from the crude methanolic extract of Wedelia calendulacea stem a HPLC fingerprint profile and liquid chromatography/sequential mass spectrometry (LC/MS) were performed.

The endocannabinoid system: a new molecular target for the treatment of tobacco addiction

Tobacco addiction is one of the leading preventable causes of mortality in the world and nicotine appears to be the main critical psychoactive component in establishing and maintaining tobacco dependence. Several lines of evidence suggest that the rewarding effects of nicotine, which underlie its abuse potential, can be modulated by manipulating the endocannabinoid system. For example, pharmacological blockade or genetic deletion of cannabinoid CB(1) receptors reduces or eliminates many behavioral and neurochemical effects of nicotine that are related to its addictive potential. This review will focus on the recently published literature about the role of the endocannabinoid system in nicotine addiction and on the endocannabinoid system as a novel molecular target for the discovery of medications for tobacco dependence.

Gaddum and LSD: the birth and growth of experimental and clinical neuropharmacology research on 5-HT in the UK

The vasoconstrictor substance named serotonin was identified as 5-hydroxytryptamine (5-HT) by Maurice Rapport in 1949. In 1951, Rapport gave Gaddum samples of 5-HT substance allowing him to develop a bioassay to both detect and measure the amine. Gaddum and colleagues rapidly identified 5-HT in brain and showed that lysergic acid diethylamide (LSD) antagonized its action in peripheral tissues. Gaddum accordingly postulated that 5-HT might have a role in mood regulation. This review examines the role of UK scientists in the first 20 years following these major discoveries, discussing their role in developing assays for 5-HT in the CNS, identifying the enzymes involved in the synthesis and metabolism of 5-HT and investigating the effect of drugs on brain 5-HT. It reviews studies on the effects of LSD in humans, including Gaddum's self-administration experiments. It outlines investigations on the role of 5-HT in psychiatric disorders, including studies on the effect of antidepressant drugs on the 5-HT concentration in rodent and human brain, and the attempts to examine 5-HT biochemistry in the brains of patients with depressive illness. It is clear that a rather small group of both preclinical scientists and psychiatrists in the UK made major advances in our understanding of the role of 5-HT in the brain, paving the way for much of the knowledge now taken for granted when discussing ways that 5-HT might be involved in the control of mood and the idea that therapeutic drugs used to alleviate psychiatric illness might alter the function of cerebral 5-HT.

Acute and long-term treatment of mania

The treatment of mania starts with a correct diagnosis and elementary measures to prevent risks for the patient, relatives, and others. Sometimes, compulsory admission and treatment may be required for a few days. Patients with psychotic or mixed mania may be more difficult to treat. At the present time, there is solid evidence supporting the use of lithium, the anticonvulsants valproate and carbamazepine, and the antipsychotics chlorpromazine, haloperidol, risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole, and asenapine in acute mania, and some evidence supporting the use of clozapine or electroconvulsive therapy in treatment-refractory cases. However, in clinical practice, combination therapy is the rule rather than the exception. The treatment of acute mania deserves a long-term view, and the evidence base for some treatments may be stronger than for others. When taking decisions about treatment, tolerability should also be a major concern, as differences in safety and tolerability may exceed differences in efficacy for most compounds. Psychoeducation of patients and caregivers is a powerful tool that should be used in combination with medication for optimal long-term outcome. Functional recovery should be the ultimate goal.

Awareness of hormesis will enhance future research in basic and applied neuroscience

Hormesis is defined operationally as responses of cells or organisms to an exogenous or intrinsic factor (chemical, temperature, psychological challenge, etc.) in which the factor induces stimulatory or beneficial effects at low doses and inhibitory or adverse effects at high doses. The compendium of articles by Calabrese entitled "Neuroscience and Hormesis" provides a broad range of examples of neurobiological processes and responses to environmental factors that exhibit biphasic dose responses, the signature of hormesis. Nerve cell networks are the "first responders" to environmental challenges--they perceive the challenge and orchestrate coordinated adaptive responses that typically involve autonomic, neuroendocrine, and behavioral changes. In addition to direct adaptive responses of neurons to environmental stressors, cells subjected to a stressor produce and release molecules such as growth factors, cytokines, and hormones that alert adjacent and even distant cells to impending danger. The discoveries that some molecules (e.g., carbon monoxide and nitric oxide) and elements (e.g., selenium and iron) that are toxic at high doses play fundamental roles in cellular signaling or metabolism suggest that during evolution, organisms (and their nervous systems) co-opted environmental toxins and used them to their advantage. Neurons also respond adaptively to everyday stressors, including physical exercise, cognitive challenges, and dietary energy restriction, each of which activates pathways linked to the production of neurotrophic factors and cellular stress resistance proteins. The development of interventions that activate hormetic signaling pathways in neurons is a promising new approach for the preventation and treatment of a range of neurological disorders.

Some neuropharamacological effects of the crude extract of Conus parvatus in mice

The present study was aimed to characterize the type of conotoxin present in Conus parvatus. (CP) belongs to family conidae, through neuro-pharmacological activities of the crude venom extract on some of the CNS animal experiment using mice as animal model. The effects of CP on CNS were studied, by using spontaneous motor activity, gross behavior, rota-rod performance, analgesic activity and potentiation of pentobarbitone sleeping time in mice. Preliminary evaluation of acute toxicity was also carried out; The LD50 value was found to be 425.20 mcg kg(-1) by i.p. route. The extract (200 mcg kg(-1) i.p.) was found to produce, reduction in spontaneous motor activity, potent analgesic activity, reduction in motor coordination and prolonged pentobarbitone-sleeping time. From the above all pharmacological activities, it may concluded that, the conotoxin present in CP is most likely to be a alpha-conotoxin and also it will be more suitable to continue the studies in the areas of analgesic and other CNS depressant therapeutic areas after isolation of the pure cono-peptide from CP.

Modelling of the blood–brain barrier in drug discovery and development

The market for neuropharmaceuticals is potentially one of the largest sectors of the global pharmaceutical market owing to the increase in average life expectancy and the fact that many neurological disorders have been largely refractory to pharmacotherapy. The brain is a delicate organ that can efficiently protect itself from harmful compounds and precisely regulate its microenvironment. Unfortunately, the same mechanisms can also prove to be formidable hurdles in drug development. An improved understanding of the regulatory interfaces that exist between blood and brain may provide novel and more effective strategies to treat neurological disorders.

Neuropharmacological profile of bifeprunox: merits and limitations in comparison with other third-generation antipsychotics

Schizophrenia is characterized by a range of positive and negative symptoms, and cognitive deficits. While positive symptoms respond to current antipsychotic agents, negative symptoms and cognitive deficits are often resistant to pharmacopea. Thus research is now focused on developing third-generation antipsychotics that combine antagonism or partial agonism at dopamine D(2)-like receptors with agonism at serotonin 5-HT(1A) receptors. Such an association is anticipated to provide therapeutic benefits against a broader range of schizophrenia symptoms. Bifeprunox is one such third-generation antipsychotic agent which acts as a partial agonist at D(2)-like receptors and is an efficacious agonist at 5-HT(1A) receptors, with little interaction at 5HT(2A/2C), muscarinic or histaminergic H(1) receptors. This review summarizes the pharmacological profiles of the current antipsychotic agents and describes the rationale behind the development of third-generation antipsychotics. It also evaluates current data concerning bifeprunox in comparison with currently available antipsychotics, as well as those that are still under clinical development.

Electrophysiological and pharmacological validation of vagal afferent fiber type of neurons enzymatically isolated from rat nodose ganglia

An unavoidable consequence of enzymatic dispersion of sensory neurons from intact ganglia is loss of the axon and thus the ability to classify afferent fiber type based upon conduction velocity (CV). An intact rat nodose ganglion preparation was used to randomly sample neurons (n=76) using the patch clamp technique. Reliable electrophysiological and chemophysiological correlates of afferent fiber type were established for use with isolated neuron preparations. Myelinated afferents (approximately 25%) formed two groups exhibiting strikingly different functional profiles. One group (n=10) exhibited CVs in excess of 10 m/s and narrow (<1 ms) action potentials (APs) while the other (n=9) had CVs as low as 4m/s and broad (>2 ms) APs that closely approximated those identified as unmyelinated afferents (n=57) with CVs less than 1m/s. A cluster analysis of select measures from the AP waveforms strongly correlated with CV, producing three statistically unique populations (p<0.05). These groupings aligned with our earlier hypothesis (Jin et al., 2004) that a differential sensitivity to the selective purinergic and vanilloid receptor agonists can be used as reliable pharmacological indicators of vagal afferent fiber type. These metrics were further validated using an even larger population of isolated (n=240) nodose neurons. Collectively, these indicators of afferent fiber type can be used to provide valuable insight concerning the relavence of isolated cellular observations to integrated afferent function of visceral organ systems.

Extracting the basal extracellular dopamine concentrations from the evoked responses: re-analysis of the dopamine kinetics

Fast-scan cyclic voltammetry in conjunction with carbon fiber microelectrode has been used to study dopamine (DA) release and uptake mechanisms in rat brains because of the smaller size of the electrode and the subsecond resolution. Current voltammetry data were analyzed by a DA kinetic model assuming a zero baseline, which is in conflict with existing microdialysis findings and a recent claim of the striatal extracellular DA concentration at micromolar levels. This work applied a new analysis approach based on a modified DA kinetic model to analyze the kinetics of electrically evoked DA overflow in the caudate-putamen of anesthetized rats. The DA uptake parameters were fitted from the electrical stimulation phase, and subsequently used to calculate theoretical DA uptake rates. Comparison of the theoretical uptake rates with experimental clearance rates allows for the study of the tonic DA release process following electrical stimulations. Analyses of DA voltammetry data suggest that the locally averaged basal level of extracellular DA in the rat striatum might be confined between 95 and 220 nM. The disparate time scales in the clearance kinetics of endogenous and exogenous DA were investigated. Long-distance diffusion could only partially explain the slow clearance time course of exogenous DA. Model simulations and parameter analyses on evoked DA responses indicate that suppression of the nonevoked DA release process immediately following electrical stimulation cannot completely account for the rapid clearance of the electrically evoked DA. Inconsistency in the measured uptake strengths in the literature studying endogenous and exogenous DA remains to be investigated in the future.

A beam-walking apparatus to assess behavioural impairments in MPTP-treated mice: pharmacological validation with R-(-)-deprenyl

A beam-walking apparatus has been evaluated for its ability to detect motor impairments in mice acutely treated with the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg, s.c., single or double administration). Mice subjected to MPTP lesioning showed deficits in motor performance on the beam-walking task, for up to 6 days post-MPTP administration, as compared to saline-treated controls. In addition, MPTP-treated mice were detected to have a marked depletion in striatal dopamine levels and a concomitant reduction in substantia nigra (SN) tyrosine hydroxylase (TH) immunoreactivity, at 7 days post-MPTP administration, indicative of dopaminergic neuronal loss. Pre-administration of the potent MAO-B inhibitor R-(-)-deprenyl at 3 or 10 mg/kg, 30 min, s.c, significantly inhibited the MPTP-induced reduction in SN TH-immunoreactivity, striatal dopamine depletions and impairments in mouse motor function. The data described in the present study provides further evidence that functional deficits following an acute MPTP dosing schedule in mice can be quantified and are related to nigro-striatal dopamine function.

A chronically implantable, hybrid cannula-electrode device for assessing the effects of molecules on electrophysiological signals in freely behaving animals

We describe a device for assessing the effects of diffusible molecules on electrophysiological recordings from multiple neurons. This device allows for the infusion of reagents through a cannula located among an array of micro-electrodes. The device can easily be customized to target specific neural structures. It is designed to be chronically implanted so that isolated neural units and local field potentials are recorded over the course of several weeks or months. Multivariate statistical and spectral analysis of electrophysiological signals acquired using this system could quantitatively identify electrical "signatures" of therapeutically useful drugs.

Schizophrenia susceptibility genes: in search of a molecular logic and novel drug targets for a devastating disorder

Schizophrenia is a devastating psychiatric disorder that affects approximately one percent of the population worldwide. We argue that the efforts to decipher the genetic causes of schizophrenia have reached another turning point and describe evidence supporting some of the major recent genetic findings in the field. In addition, we identify some general areas of caution in the interpretation of these findings and addresses the promise this recently acquired knowledge holds for the generation of reliable animal models, characterization of genetic interactions, dissection of the disease pathophysiology and development of novel, mechanism-based treatments for the patients.

Pharmacogenetics in neuropsychiatric diseases: epilepsy as a model

Individual drug responses are the result of interactions of multiple environmental and genetic factors. Pharmacogenetics studies the influence of genetic variation on interindividual differences in drug efficacy, adverse events and dosing. This article discusses general strategies for candidate gene selection and pharmacogenetic association studies. A summary of the major pharmacogenetic associations reported in neuropsychiatric disease is presented. The example of epilepsy pharmacogenetics will be covered in more detail, including an overview of epilepsy pharmacogenetic candidate genes and results of association studies reported so far. With the advent of large-scale, rigorously designed association studies, it is hoped that genetic factors will be identified that will lead to a targeted, more efficacious and safer treatment, and perhaps to the development of new and more efficacious drugs for neuropsychiatric diseases.

Microelectrode array-based system for neuropharmacological applications with cortical neurons cultured in vitro

Microelectrode arrays (MEAs) provide a means to investigate the electrophysiological behavior of neuronal systems through the measurements from neuronal culture preparations. Changes in activity patterns of neuronal networks are usually detected by applying neural chemicals. Because of the difficulties of fabricating the arrays, and the delicate and less reliable properties of cortical neurons, MEA-based systems with cortical neuronal networks for neurophamacological applications are technically difficult, therefore restricting their utility. Here, we report a new approach to the development of such MEA-based system with sensitive and durable MEAs conveniently fabricated and the culture conditions optimized. Upon growth differentiation, cortical neurons, cultured directly on MEAs, reach a developmentally stable and reliable activity state. With this system, we monitored the global spontaneous activities of neuronal networks and demonstrated the fine discrimination for specific substances and unique property of cortical neurons, which validated both the applicability and necessity of such system in pharmacological bioassay.

Applications of fMRI in translational medicine and clinical practice

Functional MRI (fMRI) has had a major impact in cognitive neuroscience. fMRI now has a small but growing role in clinical neuroimaging, with initial applications to neurosurgical planning. Current clinical research has emphasized novel concepts for clinicians, such as the role of plasticity in recovery and the maintenance of brain functions in a broad range of diseases. There is a wider potential for clinical fMRI in applications ranging from presymptomatic diagnosis, through drug development and individualization of therapies, to understanding functional brain disorders. Realization of this potential will require changes in the way clinical neuroimaging services are planned and delivered.

From systems biology to dynamical neuropharmacology: proposal for a new methodology

The concepts and methods of systems biology are extended to neuropharmacology in order to test and design drugs for the treatment of neurological and psychiatric disorders. Computational modelling by integrating compartmental neural modelling techniques and detailed kinetic descriptions of pharmacological modulation of transmitter-receptor interaction is offered as a method to test the electrophysiological and behavioural effects of putative drugs. Even more, an inverse method is suggested as a method for controlling a neural system to realise a prescribed temporal pattern. In particular, as an application of the proposed new methodology, a computational platform is offered to analyse the generation and pharmacological modulation of theta rhythm related to anxiety.

Central nervous system manifestations of mitochondrial disorders

The central nervous system (CNS) is, after the peripheral nervous system, the second most frequently affected organ in mitochondrial disorders (MCDs). CNS involvement in MCDs is clinically heterogeneous, manifesting as epilepsy, stroke-like episodes, migraine, ataxia, spasticity, extrapyramidal abnormalities, bulbar dysfunction, psychiatric abnormalities, neuropsychological deficits, or hypophysial abnormalities. CNS involvement is found in syndromic and non-syndromic MCDs. Syndromic MCDs with CNS involvement include mitochondrial encephalomyopathy, lactacidosis, stroke-like episodes syndrome, myoclonic epilepsy and ragged red fibers syndrome, mitochondrial neuro-gastrointestinal encephalomyopathy syndrome, neurogenic muscle weakness, ataxia, and retinitis pigmentosa syndrome, mitochondrial depletion syndrome, Kearns-Sayre syndrome, and Leigh syndrome, Leber's hereditary optic neuropathy, Friedreich's ataxia, and multiple systemic lipomatosis. As CNS involvement is often subclinical, the CNS including the spinal cord should be investigated even in the absence of overt clinical CNS manifestations. CNS investigations comprise the history, clinical neurological examination, neuropsychological tests, electroencephalogram, cerebral computed tomography scan, and magnetic resonance imaging. A spinal tap is indicated if there is episodic or permanent impaired consciousness or in case of cognitive decline. More sophisticated methods are required if the CNS is solely affected. Treatment of CNS manifestations in MCDs is symptomatic and focused on epilepsy, headache, lactacidosis, impaired consciousness, confusion, spasticity, extrapyramidal abnormalities, or depression. Valproate, carbamazepine, corticosteroids, acetyl salicylic acid, local and volatile anesthetics should be applied with caution. Avoiding certain drugs is often more beneficial than application of established, apparently indicated drugs.

An in vivo technique for pharmacological manipulation of Drosophila brain during optical recording

Drosophila melanogaster, an established model for genetic manipulation, has recently been used for studying olfactory perception, learning, and memory. Some of these important behavioral phenomena have been dissected with defined mutants, some to a single biochemical lesion, expressed in central brain structures known as the mushroom bodies. A previously introduced preparation used a window in the head capsule through which these structures could be imaged using genetically expressed fluorescent calcium sensors while applying physiological odorant stimuli. Unfortunately, technical constraints prevented direct manipulation of the mushroom bodies with this preparation. I describe here a preparation that will allow, for the first time, the direct pharmacological manipulation of these important structures during imaging in the living adult fly. Responses to discreet applications of acetylcholine were reversibly blocked with tubocurare and reversibly eliminated in calcium-free Ringers. This new technique will significantly enhance the usefulness of the Drosophila model system, allowing a more quantitative examination of the mechanisms involved in olfactory learning and memory.

Validation of a mechanical apparatus for the measurement of avian walking

Recent research has demonstrated that avian species may show an enhanced locomotor response to repeated drug exposure, a phenomenon called sensitization. Further research in this domain is warranted as such results not only establish the generality of previous findings, but may lend to a better understanding of sensitization in general. At present, there are no well-studied measurement devices for automating the measurement of bird movement. The present research evaluated a mechanical device comprised of moveable floor panels to assess its suitability. Evaluations of the device were made over the course of repeated cocaine administration. The results showed that there was high correspondence between the apparatus' responses and human observers' responses to movement by pigeons. The apparatus, furthermore, provided useful data on spatial orientation that revealed individual differences in the response to cocaine beyond those available from a collapsed measure of overall output. In sum, this recording strategy appears a viable instrument for the measurement of avian locomotion.

Methodological approaches to exploring epileptic disorders in the human brain in vitro

Brain surgery, and in particular epilepsy surgery, offers the unique opportunity to study viable human central nervous tissue in vitro. This does not only open a window to address the basic mechanisms underlying human disease, such as epilepsy, but it allows to venture into investigating neurophysiological functions per se. In the present paper, we describe the most commonly used methods in the electrophysiological (and, at least to some extent, also histochemical and molecular) analysis of human tissue in vitro. In addition, we consider the pitfalls and limitations of such studies, in particular regarding the issue of tissue sampling procedures and control experiments.

Reconsolidation: the advantage of being refocused

Ample evidence suggests that upon their retrieval, items in long-term memory enter a transient special state, in which they might become prone to change. The process that generates this state is dubbed 'reconsolidation'. The dominant conceptual framework in this revitalized field of memory research focuses on whether reconsolidation resembles consolidation, which is the process that converts an unstable short-term memory trace into a more stable long-term trace. However, this emphasis on the comparison of reconsolidation to consolidation deserves reassessment. Instead, the phenomenon of reconsolidation, irrespective of its relevance to consolidation, provides a unique opportunity to tap into the molecular, cellular and circuit correlates of memory persistence and retrieval, of which we currently know only little.