Effect of selective and non-selective serotonin receptor activation on L-DOPA-induced therapeutic efficacy and dyskinesia in parkinsonian rats

Selective activation of 5-HT1 receptors has been shown to produce near to full suppression of L-DOPA-induced dyskinesia (LID) in animal models of Parkinson's disease; however, a reduction of the therapeutic effect of L-DOPA has been reported in several studies. Conversely, we recently found that increasing the serotonergic tone with chronic administration of the serotonin precursor 5-hydroxy-tryptophan (5-HTP) can reduce LID in 6-OHDA-lesioned rats, without affecting L-DOPA efficacy. To directly compare the effects of selective versus non-selective serotonin receptor activation, here we first tested different acute doses of the 5-HT1A/1B receptor agonist eltoprazine and 5-HTP on LID in order to identify doses of the individual compounds showing similar anti-dyskinetic efficacy in L-DOPA-primed dyskinetic rats. About 50% reduction of LID was observed with 0.1 mg/kg and 24 mg/kg of eltoprazine and 5-HTP, respectively; we then compared the effect of the two drugs, individually and in combination, on L-DOPA-induced stepping test in L-DOPA-naïve parkinsonian animals and LID over three weeks of L-DOPA treatment. Results showed that eltoprazine induced significant worsening of L-DOPA-mediated performance in the stepping test, while 5-HTP did not. Interestingly, combination of 5-HTP with eltoprazine prevented the reduction in the forelimb use induced by eltoprazine. Moreover, 5-HTP and eltoprazine given individually showed similar efficacy also upon chronic treatment, and had additive effect in dampening the appearance of LID when given in combination. Finally, chronic administration of eltoprazine and/or 5-HTP did not affect striatal serotonin innervation, compared to l-DOPA alone, as measured by serotonin transporter expression.

Effect of serotonin transporter blockade on L-DOPA-induced dyskinesia in animal models of Parkinson's disease

Serotonin transporter blockade with selective serotonin reuptake inhibitors (SSRIs) was recently shown to counteract L-DOPA-induced dyskinesia in 6-hydroxydopamine (6-OHDA)-lesioned rats. However, this effect has never been described in Parkinson's disease (PD) patients, despite that they often receive SSRIs for the treatment of depression. In the present study, we investigated the efficacy of the SSRI citalopram against dyskinesia in two experimental models of PD, the 6-OHDA-lesioned rat and 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine (MPTP)-treated macaque. First, we studied the acute and chronic effect of citalopram, given at different time points before L-DOPA, in L-DOPA-primed parkinsonian rats. Moreover, the acute effect of citalopram was also evaluated in dyskinetic MPTP-treated macaques. In L-DOPA-primed rats, a significant and long-lasting reduction of L-DOPA-induced dyskinesia (LID) was observed only when citalopram was given 30 min before L-DOPA, suggesting that the time of injection relative to L-DOPA is a key factor for the efficacy of the treatment. Interestingly, an acute challenge with the 5-HT1A/1B receptor agonist eltoprazine, given at the end of the chronic study, was equally effective in reducing LID in rats previously chronically treated with L-DOPA or L-DOPA plus citalopram, suggesting that no auto-receptor desensitization was induced by chronic citalopram treatment. In MPTP-treated macaques, citalopram produced a striking suppression of LID but at the expense of L-DOPA therapeutic efficacy, which represents a concern for possible clinical application.

Correction: Polymers of intrinsic microporosity as high temperature templates for the formation of nanofibrous oxides

Correction for ‘Polymers of intrinsic microporosity as high temperature templates for the formation of nanofibrous oxides’ by H. Al Kutubi et al., RSC Adv., 2015, 5, 73323–73326.

Polymers of intrinsic microporosity as high temperature templates for the formation of nanofibrous oxides

Highly rigid polymers of intrinsic microporosity (PIM) offer novel high temperature template materials for the formation of nano-structured metal oxides, here for nanostructured Pr₆O₁₁.

EPA Guidance Mental Health Care of Migrants

Migration is an increasingly commonplace phenomenon for a number of reasons. People migrate from rural to urban areas or across borders for reasons including economic, educational or political. There is increasing recent research evidence from many countries in Europe that indicates that migrants are more prone to certain psychiatric disorders. Because of their experiences of migration and settling down in the new countries, they may also have special needs such as lack of linguistic abilities which must be taken into account using a number of strategies at individual, local and national policy levels. In this guidance document, we briefly present the evidence and propose that specific measures must be taken to improve and manage psychiatric disorders experienced by migrants and their descendants. This improvement requires involvement at the highest level in governments. This is a guidance document and not a systematic review.

Effect of memantine on L-DOPA-induced dyskinesia in the 6-OHDA-lesioned rat model of Parkinson's disease

An increasing body of experimental evidence demonstrates that the glutamatergic system is involved in the genesis of l-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia (LID). Indeed, the N-methyl-d-aspartate (NMDA) receptor antagonist amantadine is the only anti-dyskinetic compound used in patients, albeit with limited efficacy and side effects. In this study, we investigated the anti-dyskinetic properties of memantine, a non-competitive NMDA receptor antagonist in clinical use for the treatment of dementia, in the 6-hydroxy-dopamine (6-OHDA)-lesion rat model of Parkinson's disease. For comparison, parallel experiments were also performed with amantadine. First, we investigated the acute effect of different doses of memantine (5, 10, 15 and 20mg/kg), and amantadine (10, 20, 40, 60mg/kg) on established dyskinesia induced by L-DOPA (6mg/kg plus benserazide). Results showed that both memantine and amantadine produced a significant reduction of LID. Afterward, drug-naïve and L-DOPA-primed 6-OHDA-lesioned rats were sub-chronically treated with daily injections of L-DOPA (6mg/kg plus benserazide) alone, or in combination with the effective doses of memantine, while amantadine was tested in already dyskinetic rats. Results showed that memantine significantly dampened dyskinesia in both drug-naïve and L-DOPA-primed rats, but only during the first few days of administration. In fact, the anti-dyskinetic effect of memantine was completely lost already at the fifth administration, indicating a rapid induction of tolerance. Interestingly, a 3-week washout period was not sufficient to restore the anti-dyskinetic effect of the drug. Similarly, amantadine was able to dampen already established dyskinesia only during the first day of administration. Moreover, memantine partially decreased the therapeutic effect of L-DOPA, as showed by the result of the stepping test. Finally, loss of the anti-dyskinetic effect of memantine was associated to increased synaptic GluN2A/GluN2B ratio at striatal synaptic membranes. Our results are in line with clinical observations suggesting that NMDA receptor blockade may only be transiently effective against LID in PD patients.

A density-functional theory study of microphase formation in binary Gaussian mixtures

We use density-functional theory to study the formation of inhomogeneous phases in a binary mixture of particles interacting by repulsive, athermal Gaussian potentials with suitably chosen strengths and ranges. Both the potential parameters and the free-energy functional are the same as those adopted in a previous investigation by other authors (Archer A J, Likos C N and Evans R 2004 J. Phys.: Condens. Matter 16 L297), but here a fully numerical minimization of the functional is performed, without any assumption about the functional form of the density profile. We find lamellar, rod and cluster phases. In the lamellar phase, the two species arrange into intercalating stripes; in the rod and cluster phases, the minority species is localized at the site of a periodic lattice, either triangular (for rods) or body-centred cubic (for clusters), while the other species is distributed non-uniformly in the remaining region, so that it forms a percolating network. The order of the transition from the homogeneous to the inhomogeneous phase and the phase diagram of the mixture are also discussed.

Contribution of pre-synaptic mechanisms to L-DOPA-induced dyskinesia

Positron emission tomography (PET) imaging studies have shown that peak-dose dyskinesia is associated to abnormally high levels of synaptic dopamine (DA) in the caudate-putamen of dyskinetic L-DOPA-treated patients. High striatal extracellular DA levels have also been found in dyskinetic 6-OHDA-lesioned rats as compared to non-dyskinetic ones, suggesting that extracellular DA levels may play a key role in the induction of dyskinesia. In this article we review the evidences pointing to the serotonin system as the primary cause for the abnormally high levels of L-DOPA-derived extracellular DA in Parkinson's disease, and we discuss the feasibility of a therapeutic approach targeting this system.

Parallel conduction of the phase I preventive and therapeutic trials based on the Tat vaccine candidate

The native HIV-1 Tat protein was chosen as vaccine candidate for phase I clinical trials in both uninfected (ClinicalTrials.gov identifier: NCT00529698) and infected volunteers (ClinicalTrials.gov identifier: NCT00505401). The rationale was based on the role of Tat in the natural infection and AIDS pathogenesis, on the association of Tat-specific immune responses with the asymptomatic stage and slow-progression rate as well as on its sequence conservation among HIV clades (http://www.hiv1tat-vaccines.info/). The parallel conduction in the same clinical centers of randomized, double blind, placebo-controlled phase I studies both in healthy, immunologically competent adults and in HIV-infected, clinically asymptomatic, individuals represents a unique occasion to compare the vaccine-induced immune response in both the preventive and therapeutic setting. In both studies, the same lot of the native Tat protein was administered 5 times, every four weeks, subcute (SC) with alum adjuvant or intradermic (ID), in the absence of adjuvant, at 7.5 microg, 15 microg or 30 microg doses, respectively. The primary and secondary endpoints of these studies were the safety and immunogenicity of the vaccine candidate, respectively. The study lasted 52 weeks and monitoring was conducted for on additional 3 years. The results of both studies indicated that the Tat vaccine is safe and well tolerated both locally and systemically and it is highly immunogenic at all the dosages and by both routes of administration. Vaccination with Tat induced a balanced immune response in uninfected and infected individuals. In particular, therapeutic immunization induced functional antibodies and partially reverted the marked Th1 polarization of anti-Tat immunity seen in natural infection, and elicited a more balanced Th1/Th2 immune response. Further, the number of CD4 T cells correlated positively with anti-Tat antibody titers. Based on these results, a phase II study is ongoing in infected drug-treated individuals (http://www.hiv1tat-vaccines.info/).

The Use of Drugs for Mood Disorders in Italy: Preliminary Results

Background:

Some community surveys in Italy have shown that a proportion of subjects without lifetime psychiatric diagnosis (anxiety/depression) used antidepressants. The prescription of AD in bipolar depression appears to be another largely underestimated problem in the clinical practice and is difficult to recognise by means of traditional epidemiological methods (lay interview and structured diagnostic tools).

Objectives:

The purpose is to use defined and validated international semi-structured interview as diagnostic instrument administered by expert clinicians to evaluate appropriateness and amount of over and under prescription of psychotropic drugs in different Italian community areas. The focus is on general antidepressant use and use in subjects with bipolar disorder and in subsyndromal depression.

Methods:

Study design: Community survey. Study population: sample randomly drawn, after stratification by sex and age, from the adult population of Municipal records in 6 Italian Regions: about 4000 persons will be interviewed. Tools: Questionnaire on psychotropic drugs consumption, prescription, health services utilisation;diagnostic Structured Clinical Interview np version;Mood Disorders Questionnaire; Short Form Health Survey. Ethical aspects: a signed informed consent for each candidate. The study was approved by the ethical committee of theItalain National Health Institute.

Expected results:

The study aims to identify the frequency of over and under prescription of psychotropic drugs in different Italian regions and the determinants of prescription related to physicians, patients, comorbidity and symptoms and to establish the basis for a cohort prospective study to assess the future changes.

Isoniazid-induced reduction in GABAergic neurotransmission alters the function of the cerebellar cortical circuit

The cerebellar cortex contributes to the control of movement, coordination, and certain cognitive functions. The cerebellar network is composed of five different types of neurons that are wired together in a repetitive module. Given that four of these five neurons synthesize and release GABA, this inhibitory neurotransmitter plays a central role in regulation of the excitability and correct functioning of the cerebellar cortex. We have now used isoniazid, an inhibitor of glutamic acid decarboxylase, the enzyme responsible for the synthesis of GABA, to evaluate the contribution of GABAergic transmission in different types of cerebellar cortical neurons to the functioning of the cerebellar circuit. Parasagittal cerebellar slices were prepared from 28- to 40-day-old male rats and were subjected to patch-clamp recording in the voltage- or current-clamp mode. Exposure of the tissue slices to isoniazid (10 mM) resulted in a decrease in the level of GABAergic transmission in Purkinje cells and a consequent increase in the firing rate of spontaneous action potentials that was apparent after 40 min. In granule neurons, isoniazid reduced both tonic and phasic GABAergic currents and thereby altered the flow of information across the cerebellar cortex. Our data support the notion that the amount of GABA at the synaptic level is a major determinant of the excitability of the cerebellar cortex, and they suggest that isoniazid may be a useful tool with which to study the function of the cerebellar network.

Augmented cocaine-induced accumbal dopamine efflux, motor activity and place preference in rats fed with a tryptophan-deficient diet

In the present study we demonstrate that consumption of a tryptophan-deficient diet for a period of 14 days decreased the striatal serotonin and 5-hydroxyindolacetic acid tissue content in rats, whereas the level of dopamine remained unchanged. Under this condition of diminished serotonergic tone, a challenge dose of cocaine (10mg/kg, i.p.) significantly increased motor activity and dopamine extracellular content in the nucleus accumbens compared to rats fed with a balanced diet. We moreover found that pretreatment with cocaine (7 and 10mg/kg, i.p.) produced a significant increase in preference for a cocaine-associated environment in the tryptophan-deficient group compared to control rats. Our experiments show that a low tone of serotonergic system, augments the behavioural reinforcing effect of cocaine and that this effect may be due to a increased cocaine-induced accumbal dopamine release. These data indicate that a tryptophan-deficient diet alters the behavioural and neurochemical effect of psychostimulants, such as cocaine, and suggest an important role of serotonin in modulation of these effects.

Primary leiomyosarcoma of the oral tongue: magnetic resonance and ultrasonography findings with histopathologic correlation

Leiomyosarcoma is a malignant smooth muscle tumor that frequently occurs in the gastrointestinal tract and female genital tract. It is aggressive and tends to recur and metastasize. Clinical behavior is unpredictable, mostly influenced by a proper surgical approach. Oral leiomyosarcoma, in particular of the tongue, is extremely rare and poorly documented in the radiology literature. Diagnostic assessment of oral leiomyosarcoma is often challenging, mostly founded on its peculiar immunohistological features. However, imaging evaluation is essential in staging and for preoperative planning. We illustrate the case of a 52-year-old woman with 2-months history of a painless growing mass on the left hemitongue, with magnetic resonance and ultrasonographic features correlated to histopathologic examination.

Basis of the gabamimetic profile of ethanol

This article summarizes the proceedings of a symposium held at the 2005 Research Society on Alcoholism meeting. The initial presentation by Dr. Wallner provided evidence that selected GABA(A) receptors containing the delta subunit display sensitivity to low intoxicating ethanol concentrations and this sensitivity is further increased by a mutation in the cerebellar alpha6 subunit, found in alcohol-hypersensitive rats. Dr. Mameli reported that ethanol affects gamma-aminobutyric acid (GABA) function by affecting neural circuits that influence GABA release. Dr. Parsons presented data from electrophysiological and microdialysis investigations that ethanol is capable of releasing GABA from presynaptic terminals. Dr. Morrow demonstrated that systemic ethanol increases neuroactive steroids in brain, the absence of which alters various functional responses to ethanol. Dr. Criswell presented evidence that the ability of ethanol to increase GABA was apparent in some, but not all, brain regions indicative of regional specificity. Further, Dr. Criswell demonstrated that neurosteroids alone and when synthesized locally by ethanol act postsynaptically to enhance the effect of GABA released by ethanol in a region specific manner. Collectively, this series of reports support the GABAmimetic profile of acutely administered ethanol being dependent on several specific mechanisms distinct from a direct effect on the major synaptic isoforms of GABA(A) receptors.

Primary repair in esophageal atresia. The results of long term follow-up

AIM

The aim of this study was to assess the impact of postoperative morbidity during a long-term follow-up (6-12 years) in children with esophageal atresia treated at birth by primary anastomosis.

METHODS

Fifteen children with esophageal atresia and tracheoesophageal fistula were surgically treated at birth and their follow-up was extended to at least 6 up to 12 years. Data included clinical examination, evaluation of nutritional habit, continuous video recording of barium esophagogram, esophageal manometry, 24-h esophageal pH-monitoring and esophageal endoscopy.

RESULTS

All the 15 patients completed the clinical evaluation and the set of tests. In the first 6 years, mild dysphagia and gastroesophageal reflux (GER) was observed in 3 cases whereas GER without dysphagia in 4 cases. These 7 patients were informed about simple nutritional behaviours to minimize symptoms and treated with H2-blockers. At long-term twelve-year analysis, all patients were between 50 degrees and 75 degrees percentile of expected growth. It was not referred peculiar food restrictions. Five patients showed mild dysphagia with solid foods; early satiety, epigastric burning and regurgitation were less frequent. Furthermore they showed multiple non-peristaltic body contractions at esophagogram and moderate impairment of esophageal motility at esophageal manometry. The 24-h esophageal pH-monitoring showed normal patterns in all patients. No major lesions of esophageal mucosa were detected at esophagoscopy.

CONCLUSIONS

Although GER and esophageal dysmotility are reported as frequent findings in patients who underwent primary repair for esophageal atresia, these disorders don't cause any relevant impairment to the quality of their nutritional habit.

Vitamin A deficiency induces motor impairments and striatal cholinergic dysfunction in rats

Vitamin A and its derivatives, retinoids, are involved in the regulation of gene expression by binding two nuclear receptor families, retinoic acid receptors and retinoid X receptors. Retinoid receptors are highly expressed in the striatum, revealing an involvement of this system in the control of movement as demonstrated by previous observations in knockout mice. To further assess the role of retinoids in adult striatal function, the present study investigated the effect of vitamin A deprivation on rat motor activity and coordination, the rate of synthesis and release of dopamine, the functioning of D1 and D2 receptors and their expression in the striatum. Moreover, the content of acetylcholine in the striatum was measured. Results show that 24 weeks of postnatal vitamin A deprivation induced severe locomotor deficits and impaired motor coordination. Vitamin A deprivation rats showed a significant hyperactivity following D1 receptor stimulation by R(+)-6-chloro-7,8-dihydroxy-1-phenyil-2,3,4,5-tetrahydro-1H-3-benzazepine or amphetamine and reduced catalepsy in response to haloperidol treatment. This different response to the above drugs is not due to a change in striatal DA release or synthesis between vitamin A deprivation and control animals. In situ hybridization experiments showed identical level of expression for the D1 and D2 receptor transcripts. On the other hand, the striatal tissue content of acetylcholine was reduced significantly by about 30% starting from the initial manifestation of motor deficits. We suggest that the locomotor impairment could be imputable to the dysfunction in striatal cholinergic interneurons. Our results stress the basic role of vitamin A in the maintenance of basal ganglia motor function in the adult rat brain.