SNPs in cytochrome P450 genes decide on the fate of individuals with genetic predisposition to Parkinson's disease.

Parkinson's disease (PD) is one of the most frequent neurological diseases affecting millions of people worldwide. While the majority of PD cases are of unknown origin (idiopathic), about 5%-10% are familial and linked to mutations in different known genes. However, there are also people with a genetic predisposition to PD who do not develop the disease. To elucidate factors leading to the manifestation of PD we compared the occurrence of single nucleotide polymorphisms (SNPs) in various cytochrome P450 (P450) genes in people with a genetic predisposition and suffering from PD (GPD) to that of people, who are genetically predisposed, but show no symptoms of the disease (GUN). We used the PPMI (Parkinson's Progression Markers Initiative) database and the gene sequences of all 57 P450s as well as their three redox partners. Corresponding odds ratios (OR) and confidence intervals (CI) were calculated to assess the incidence of the various SNPs in the two groups of individuals and consequently their relation to PD. We identified for the first time SNPs that are significantly (up to 10fold!) over- or under-represented in GPD patients compared to GUN. SNPs with OR > 5 were found in 10 P450s being involved in eicosanoid, vitamin A and D metabolism as well as cholesterol degradation pointing to an important role of endogenous factors for the manifestation of PD clinical symptoms. Moreover, 12 P450s belonging to all P450 substrate classes as well as POR have SNPs that are significantly under-represented (OR < 0.2) in GPD compared to GUN, indicating a protective role of those SNPs and the corresponding P450s regarding disease advancement. To the best of our knowledge our data for the first time demonstrate an association between known PD predisposition genes and SNPs in other genes, shown here for different P450 genes and for their redox partner POR, which promote the manifestation of the disease in familial PD. Our results thus shed light onto the pathogenesis of PD, especially the switch from GUN to GPD and might further help to advance novel strategies for preventing the development or progression of the disease.

Effect of the mGlu4 positive allosteric modulator ADX-88178 on parkinsonism, psychosis-like behaviours and dyskinesia in the MPTP-lesioned marmoset.

RATIONALE: Positive allosteric modulation of metabotropic glutamate type 4 (mGlu4) receptors is a promising strategy to alleviate parkinsonian disability and L-3,4-dihydroxyphenylalanine (L-DOPA) induced dyskinesia. ADX-88178 is a highly selective mGlu4 positive allosteric modulator (PAM) that previously enhanced the anti-parkinsonian action of L-DOPA in the 6-hydroxydopamine-lesioned rat model of Parkinson's disease (PD). OBJECTIVES: We sought to explore the effects of ADX-88178 on psychosis-like behaviours (PLBs) in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned marmoset. We also aimed to determine the effect of ADX-88178 on parkinsonism and dyskinesia. METHODS: Six MPTP-lesioned marmosets were administered L-DOPA chronically to induce stable PLBs and dyskinesias. They were then administered ADX-88178 (0.01, 0.1 and 1 mg/kg) or vehicle, in combination with L-DOPA/benserazide (15/3.75 mg/kg), both sub-cutaneously, in a randomised fashion. PLBs, parkinsonism and dyskinesia were then measured. RESULTS: ADX-88178 mildly worsened global PLBs at the dose of 1 mg/kg (by 13%, P = 0.020). L-DOPA alone conferred 158 min of on-time, while the duration of on-time was 212 min (34% increase, P = 0.011), after adding ADX-88178 1 mg/kg to L-DOPA. Accordingly, ADX-88178 1 mg/kg reduced global parkinsonian disability, by 38% (P = 0.0096). ADX-88178 1 mg/kg diminished peak dose dyskinesia by 34% (P = 0.015). Minimal effects were provided by lower doses. CONCLUSIONS: Whereas these results provide additional evidence of the anti-parkinsonian and anti-dyskinetic effects of mGlu4 positive allosteric modulation as an adjunct to L-DOPA, they also suggest that ADX-88178 may exacerbate dopaminergic psychosis. Further studies are needed to evaluate this possible adverse effect of mGlu4 PAMs on PD psychosis.

Epilepsy: expert opinion on emerging drugs in phase 2/3 clinical trials.

INTRODUCTION: Despite the existence of over 30 anti-seizure medications (ASM), including 20 over the last 30 years, a third of patients with epilepsy remain refractory to treatment, with no disease-modifying or preventive therapies until very recently. The development of new ASMs with new mechanisms of action is therefore critical. Recent clinical trials of new treatments have shifted focus from traditional common epilepsies to rare, genetic epilepsies with known mechanistic targets for treatment and disease-specific animal models. AREAS COVERED: ASMs in phase 2a/b-3 clinical trials target cholesterol, serotonin, sigma-1 receptors, potassium channels and metabotropic glutamate receptors. Neuroinflammation, protein misfolding, abnormal thalamocortical firing, and molecular deficiencies are among the targeted pathways. Clinically, the current phase 2a/b-3 agents hold promise for variety of epilepsy conditions, from developmental epileptic encephalopathies (Dravet Syndrome, Lennox-Gastaut syndrome, CDKL5 and PCDH19, Rett's Syndrome), infantile spasms, tuberous sclerosis as well as focal and idiopathic generalized epilepsies and acute rescue therapy for cluster seizures. EXPERT OPINION: New delivery mechanisms increase potency and site-specificity of existing drugs. Novel mechanisms of action involve cholesterol degradation, mitochondrial pathways, anti-inflammation, and neuro-regeneration. Earlier identification of genetic conditions through genetic testing will allow for earlier use of disease specific and disease-modifying therapies.

Sjögren-Larsson syndrome: A biochemical rationale for using aldehyde-reactive therapeutic agents.

Sjögren-Larsson syndrome (SLS) is a neurocutaneous disease caused by mutations in ALDH3A2 that result in deficient fatty aldehyde dehydrogenase (FALDH) activity and impaired fatty aldehyde and fatty alcohol oxidation. The pathogenesis of SLS is thought to involve accumulation of long-chain fatty aldehydes and alcohols and/or metabolically-related ether glycerolipids. Fatty aldehydes are particularly toxic molecules that can covalently react with proteins and certain amino-containing lipids such as phosphatidylethanolamine (PE), generating an unusual aldehyde adduct, N-alkyl-PE (NAPE). Using Faldh-deficient Chinese hamster ovary cells (FAA-K1A) as a cellular model for SLS, we investigated the ability of an aldehyde trapping agent, ADX-102 [2-(3-amino-6-chloro-quinolin-2-yl)-propan-2-ol], to mitigate the harmful effects of fatty aldehydes. FAA-K1A cells were protected from octadecanal (C18:0-al) induced cytotoxicity and apoptosis by ADX-102. Metabolism of C18:0-al to fatty alcohol (octadecanol) was also inhibited by ADX-102. FAA-K1A cells accumulated 5-fold more NAPE with C16- and C18-linked N-alkyl chains compared to wild-type cells, but NAPE levels decreased to normal after growth for 4 days with 50 µM ADX-102. Our results suggest that small aldehyde-reactive molecules, such as ADX-102, should be explored as novel therapeutic agents for SLS by preventing aldehyde adduct formation with critical cellular targets and inhibiting fatty aldehyde metabolism to fatty alcohol.

A CYPome-wide study reveals new potential players in the pathogenesis of Parkinson's disease.

Genetic and environmental factors lead to the manifestation of Parkinson's disease (PD) but related mechanisms are only rudimentarily understood. Cytochromes P450 (P450s) are involved in the biotransformation of toxic compounds and in many physiological processes and thus predestinated to be involved in PD. However, so far only SNPs (single nucleotide polymorphisms) in CYP2D6 and CYP2E1 have been associated with the susceptibility of PD. Our aim was to evaluate the role of all 57 human P450s and their redox partners for the etiology and pathophysiology of PD and to identify novel potential players which may lead to the identification of new biomarkers and to a causative treatment of PD. The PPMI (Parkinson's Progression Markers Initiative) database was used to extract the gene sequences of all 57 P450s and their three redox partners to analyze the association of SNPs with the occurrence of PD. Applying statistical analyses of the data, corresponding odds ratios (OR) and confidence intervals (CI) were calculated. We identified SNPs significantly over-represented in patients with a genetic predisposition for PD (GPD patients) or in idiopathic PD (IPD patients) compared to HC (healthy controls). Xenobiotic-metabolizing P450s show a significant accumulation of SNPs in PD patients compared with HC supporting the role of toxic compounds in the pathogenesis of PD. Moreover, SNPs with high OR values (>5) in P450s catalyzing the degradation of cholesterol (CYP46A1, CY7B1, CYP39A1) indicate a prominent role of cholesterol metabolism in the brain for PD risk. Finally, P450s participating in the metabolism of eicosanoids show a strong over-representation of SNPs in PD patients underlining the effect of inflammation on the pathogenesis of PD. Also, the redox partners of P450 show SNPs with OR > 5 in PD patients. Taken together, we demonstrate that SNPs in 26 out of 57 P450s are at least 5-fold over-represented in PD patients suggesting these P450s as new potential players in the pathogenesis of PD. For the first time exceptionally high OR values (up to 12.9) were found. This will lead to deeper insight into the origin and development of PD and may be applied to develop novel strategies for a causative treatment of this disease.

Targeted methods for molecular characterization of EGFR mutational profile in lung cancer Moroccan cohort.

The study of EGFR gene mutational profile in NSCLC patients has a special clinical significance in the selection of patients for tyrosine-kinase inhibitors therapy. From 2017, the targeted therapy started to be accessible in public sector in Morocco, thus, the implementation of techniques for the molecular characterization of EGFR mutations in the laboratories became a necessity. The aim of this study was to present targeted methods "ADx-ARMS technology and the Idylla™ system" for the identification of EGFR mutational profile, methods that can be implemented in our clinical laboratories for routine analysis instead of outsourcing analysis to other countries. We conducted this study by processing 239 cases of NSCLC patients. Using the DNA extracted from the FFPE tissue, we evaluated somatic mutations in exons 18 to 21 of the tyrosine-kinase domain of EGFR gene by HRM-PCR combined to real time PCR "ADx-ARMS technology" and Idylla™ system. These sensitive methods showed that among the positive mutant cases, the distribution of mutations was as follows: 70% of patients having a deletion in exon 19, 15% in exon 21 (L858R), 7.5% in exon 20 and 7.5% in exon 18 (G719X). All of the positive EGFR mutations cases were adenocarcinoma and 42.1% of them were smokers. These results show the need to incorporate a quick and efficient method for the identification of EGFR mutation into routine practice in our laboratories, allowing more patients to benefit from targeted therapy.

Negative Allosteric Modulators of mGlu7 Receptor as Putative Antipsychotic Drugs.

The data concerning antipsychotic-like activity of negative allosteric modulators (NAMs)/antagonists of mGlu7 receptors are limited. The only available ligands for this receptor are MMPIP and ADX71743. In the present studies, we used stable cell line expressing mGlu7 receptor and it was shown that both compounds dose-dependently potentiated forskolin elevated cAMP concentration in the T-REx 293 cells, showing their inverse agonist properties. Subsequently, pharmacokinetic studies were performed. Both compounds were given intraperitoneally (i.p.) at the dose of 10 mg/kg and reached Cmax 0.25-0.5 h after administration, and then they declined rapidly, ADX71743 being almost undetectable 2 h after administration, while the concentration of MMPIP was still observed, suggesting that the concentration of MMPIP was more stable. Finally, we investigated the role of both mGlu7 receptor NAMs in animal models of schizophrenia. Behavioral tests commonly used in antipsychotic drug discovery were conducted. Both tested compounds dose-dependently inhibited MK-801-induced hyperactivity (MMPIP at 15 mg/kg; ADX at 5 and 15 mg/kg) and DOI-induced head twitches (MMPIP at 5, 10, 15 mg/kg; ADX at 2.5, 5, 10 mg/kg). Moreover, the same effects were noticed in novel object recognition test, where MMPIP (5, 10, 15 mg/kg) and ADX71743 (1, 5, 15 mg/kg) reversed MK-801-induced disturbances. In the social interaction test, antipsychotic activity was observed only for ADX71743 (5, 15 mg/kg). ADX71743 at the dose 2.5 mg/kg reversed MK-801-induced disruption in prepulse inhibition while MMPIP at 10 mg/kg reversed MK-801-induced disruption in spatial delayed alternation. The present studies showed that mGlu7 receptor may be considered as a putative target for antipsychotic drugs, though more studies are needed due to limited number of available ligands.

Immunotherapy in Prostate Cancer: Teaching an Old Dog New Tricks.

Immunotherapy is rapidly transforming cancer care across a range of tumor types. Although Sipuleucel-T represented the first successful vaccine for the treatment of established cancer, other immunotherapeutic approaches for prostate cancer such as checkpoint inhibitors have been relatively disappointing to date. However, significant promise is on the horizon as there is a wide array trials evaluating immunotherapy in prostate cancer patients. These include both immune checkpoint inhibitors and antigen-specific approaches including vaccines, antibody-drug conjugates, and antitumor antibodies. Furthermore, a better understanding of the key mechanisms that promote the immunosuppressive microenvironment of prostate cancer is emerging. These insights may eventually make it possible to determine which patients will benefit from immunotherapy. This review will discuss the successes and failures of immunotherapy in prostate cancer. We will also present key lessons learned from completed trials and highlight important ongoing studies.

Genetic Reduction or Negative Modulation of mGlu7 Does Not Impact Anxiety and Fear Learning Phenotypes in a Mouse Model of MECP2 Duplication Syndrome.

Rett syndrome and MECP2 Duplication syndrome are neurodevelopmental disorders attributed to loss-of-function mutations in, or duplication of, the gene encoding methyl-CpG-binding protein 2 (MeCP2), respectively. We recently reported decreased expression and function of the metabotropic glutamate receptor 7 (mGlu7) in a mouse model of Rett syndrome. Positive allosteric modulation of mGlu7 activity was sufficient to improve several disease phenotypes including cognition. Here, we tested the hypothesis that mGlu7 expression would be reciprocally regulated in a mouse model of MECP2 Duplication syndrome, such that negative modulation of mGlu7 activity would exert therapeutic benefit. To the contrary, we report that mGlu7 is not functionally increased in mice overexpressing MeCP2 and that neither genetic nor pharmacological reduction of mGlu7 activity impacts phenotypes that are antiparallel to those observed in Rett syndrome model mice. These data expand our understanding of how mGlu7 expression and function is affected by changes in MeCP2 dosage and have important implications for the therapeutic development of mGlu7 modulators.

Identifying clinically important difference on the Epworth Sleepiness Scale: results from a narcolepsy clinical trial of JZP-110.

BACKGROUND: While scores ≤10 on the Epworth Sleepiness Scale (ESS) are within the normal range, the reduction in elevated ESS score that is clinically meaningful in patients with narcolepsy has not been established. METHODS: This post hoc analysis of a clinical trial of patients with narcolepsy evaluated correlations between Patient Global Impression of Change (PGI-C) and ESS. Data of adult patients with narcolepsy from a double-blind, 12-week placebo-controlled study of JZP-110, a wake-promoting agent, were used in this analysis. Descriptive statistics and receiver operating characteristic (ROC) analysis compared PGI-C (anchor measure) to percent change from baseline in ESS to establish the responder criterion from patients taking either placebo or JZP-110 (treatments). RESULTS: At week 12, patients (n = 10) who reported being "very much improved" on the PGI-C had a mean 76.7% reduction in ESS score, and patients (n = 33) who reported being "much improved" on the PGI-C had a mean 49.1% reduction in ESS score. ROC analysis showed that patients who improved were almost exclusively from JZP-110 treatment group, with an area-under-the-curve of 0.9, and revealed that a 25% reduction in ESS (sensitivity, 81.4%; specificity, 80.9%) may be an appropriate threshold for defining a meaningful patient response to JZP-110 and placebo. CONCLUSIONS: A ≥25% reduction in patients' subjective ESS score may be useful as a threshold to identify patients with narcolepsy who respond to JZP-110 treatment.

Characterizing and predicting the Nelson-Salassa syndrome.

OBJECTIVE Nelson-Salassa syndrome (NSS) is a rare consequence of bilateral adrenalectomy (ADX) for refractory hypercortisolism due to Cushing disease (CD). Although classically defined by rapid growth of a large, invasive, adrenocorticotropin hormone (ACTH)-secreting pituitary tumor after bilateral ADX that causes cutaneous hyperpigmentation, visual disturbance, and high levels of ACTH, clinical experience suggests more variability. METHODS The authors conducted a retrospective chart review of all patients 18 years and older with a history of bilateral ADX for CD, adequate pituitary MRI, and at least 2 years of clinical follow-up. Statistical tests included Student's t-test, chi-square test, Fisher's exact test, multivariate analysis, and derived receiver operating characteristic curves. RESULTS Between 1956 and 2015, 302 patients underwent bilateral ADX for the treatment of hypercortisolism caused by CD; 88 had requisite imaging and follow-up (mean 16 years). Forty-seven patients (53%) had radiographic progression of pituitary disease and were diagnosed with NSS. Compared with patients who did not experience progression, those who developed NSS were significantly younger at the time of CD diagnosis (33 vs 44 years, p = 0.007) and at the time of bilateral ADX (35 vs 49 years, p = 0.007), had larger tumors at the time of CD diagnosis (6 mm vs 1 mm, p = 0.03), and were more likely to have undergone external-beam radiation therapy (EBRT, 43% vs 12%, p = 0.005). Among NSS patients, the mean tumor growth was 7 mm/yr (SE 6 mm/yr); the median tumor growth was 3 mm/yr. Prevalence of pathognomonic symptoms was low; the classic triad occurred in 9%, while hyperpigmentation without visual field deficit was observed in 23%, and 68% remained asymptomatic despite radiographic disease progression. NSS required treatment in 14 patients (30%). CONCLUSIONS NSS is a prevalent sequela of CD after bilateral ADX and affects more than 50% of patients. However, although radiological evidence of NSS is common, it is most often clinically indolent, with only a small minority of patients developing the more aggressive disease phenotype characterized by clinically meaningful symptoms and indications for treatment. Young age at the time of CD diagnosis or treatment with bilateral ADX, large tumor size at CD diagnosis, and EBRT are associated with progression to NSS and may be markers of aggressiveness.

ADX71943 and ADX71441, novel positive allosteric modulators of the GABAB receptor with distinct central/peripheral profiles, show efficacy in the monosodium iodoacetate model of chronic osteoarthritis pain in the rat.

We tested novel positive allosteric modulators (PAMs) of the γ-aminobutyric acid receptor B (GABAB), ADX71943 and ADX71441in the monosodium iodoacetate model of chronic osteoarthritis pain in rats with the objective to delineate the role of peripheral versus central GABAB receptor populations in modulation of chronic pain. Anesthetized Sprague-Dawley rats received an injection of monosodium iodoacetate into the knee and were tested for hyperalgesia starting post-MIA day 14. Effects of compounds on ipsilateral joint compression threshold were evaluated on post-MIA day 14 (after acute treatment), as well as after repeated, daily treatment on days 21 and 28 (ADX71943 only) and were compared to those of celecoxib (30mg/kg, p.o.). The PAMs were also tested in the rat rotarod test for potential muscle-relaxant effects. Acutely, ADX71943 (1-30mg/kg, p.o.), the peripherally restricted PAM, resulted in similar increases in pain threshold across the doses on day 14, while showing reduced efficacy on day 21 and no efficacy on day 28. A clear reduction in the efficacy of celecoxib across testing was also noted in this experiment. Acutely ADX71441 (0.3-15mg/kg, p.o.), the central-peripheral PAM, resulted in over 2-fold increases in pain threshold at 15mg/kg (but not at lower doses) on day 14, while causing more modest effects on day 21. Celecoxib increased pain threshold after both acute and daily treatment, showing overall similar efficacy. Thus, early, presumably more inflammatory phase of osteoarthritis pain in more sensitive to GABAB PAMs with peripherally restricted profile, while later, presumably more neuropathic phase is more sensitive to PAMs with central-peripheral profile.

Radiosynthesis and evaluation of 5-methyl-N-(4-[(11)C]methylpyrimidin-2-yl)-4-(1H-pyrazol-4-yl)thiazol-2-amine ([(11)C]ADX88178) as a novel radioligand for imaging of metabotropic glutamate receptor subtype 4 (mGluR4).

ADX88178 (1) has been recently developed as a potent positive allosteric modulator for metabotropic glutamate receptor 4 (mGluR4). The aim of this study was to develop [(11)C]1 as a novel positron emission tomography ligand and to evaluate its binding ability for mGluR4. Using stannyl precursor 3, [(11)C]1 was efficiently synthesized by introducing an [(11)C]methyl group into a pyrimidine ring via C-(11)C coupling and deprotection reactions, in 16±6% radiochemical yield (n=10). At the end of synthesis, 0.54-1.10GBq of [(11)C]1 was acquired with >98% radiochemical purity and 90-120GBq/µmol of specific activity. In vitro autoradiography and ex vivo biodistribution study in rat brains showed specific binding of [(11)C]1 in the cerebellum, striatum, thalamus, cerebral cortex, and medulla oblongata, which showed dose-dependent decreases by administration with multi-dose of unlabeled 1.

Relationship between impaired adipogenesis of retroperitoneal adipose tissue and hypertrophic obesity: role of endogenous glucocorticoid excess.

Although the pro-adipogenic effect of glucocorticoid (GC) on adipose tissue (AT) precursor cell differentiation is openly accepted, the effect of chronically high peripheral levels of GC on AT mass expansion is not fully understood. In the present study, we aim to assess the in vitro adipogenic capacity of AT precursor cells isolated from retroperitoneal (RP) AT pads of the hypercorticosteronaemic, adult neonatally treated monosodium L-glutamate (MSG) male rat. To ascertain this issue, we explored the in vitro adipogenic process of stromal-vascular fraction (SVF) cells isolated from RPAT pads of 60-day-old MSG rats. The data recorded indicated that RPAT-SVF cells from hypercorticosteronaemic MSG rats, although displaying an enhanced proliferation capacity, differentiated slower than normal cells. This dysfunction was associated with a reduction in key parameters indicative of precursor cell commitment, differentiation capacity and the percentage of fully differentiated adipocytes, with a retarded maturation process. The distorted adipogenic capacity was highly conditioned by RPAT-SVF cells displaying a low committed population and both excessive and reduced expression of anti- (Pref-1 and Wnt-10b) and pro-adipogenic (mineralocorticoid receptor) signals respectively. Notably, the normalization of peripheral corticosterone levels in MSG rats, as a result of bilateral adrenalectomy combined with GC replacement therapy, fully prevented reduced RPAT precursor cell commitment and overall impaired adipogenesis. Our study strongly supports that the impaired adipogenic process observed in the adult hypertrophic obese MSG male rat is a GC-dependent mechanism, thus explaining the unhealthy RPAT expansion observed in human hypertrophic obese phenotypes, such as in the Cushing's syndrome.

Development of allosteric modulators of GPCRs for treatment of CNS disorders.

The discovery of allosteric modulators of G protein-coupled receptors (GPCRs) provides a promising new strategy with potential for developing novel treatments for a variety of central nervous system (CNS) disorders. Traditional drug discovery efforts targeting GPCRs have focused on developing ligands for orthosteric sites which bind endogenous ligands. Allosteric modulators target a site separate from the orthosteric site to modulate receptor function. These allosteric agents can either potentiate (positive allosteric modulator, PAM) or inhibit (negative allosteric modulator, NAM) the receptor response and often provide much greater subtype selectivity than orthosteric ligands for the same receptors. Experimental evidence has revealed more nuanced pharmacological modes of action of allosteric modulators, with some PAMs showing allosteric agonism in combination with positive allosteric modulation in response to endogenous ligand (ago-potentiators) as well as "bitopic" ligands that interact with both the allosteric and orthosteric sites. Drugs targeting the allosteric site allow for increased drug selectivity and potentially decreased adverse side effects. Promising evidence has demonstrated potential utility of a number of allosteric modulators of GPCRs in multiple CNS disorders, including neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, as well as psychiatric or neurobehavioral diseases such as anxiety, schizophrenia, and addiction.

Flattening plasma corticosterone levels increases the prevalence of serotonergic dorsal raphe neurons inhibitory responses to nicotine in adrenalectomised rats.

Major depression is characterized by a diminished activity of the brain serotonergic system as well as by the flattening of plasma cortisol levels. Nicotine improves mood in patients with major depression and in experimentally depressed animals by increasing brain serotonin (5-HT), noradrenaline and dopamine levels. The present study was directed to determine if flattening plasma glucocorticoid levels changes nicotine's stimulatory effects upon 5-HT DRN neurons. The experiments were performed in brain slices obtained from rats previously (14 days) adrenalectomised and implanted subcutaneously with one pellet containing 75mg of corticosterone (Adx+CSR rats). Whole cell voltage and current clamp techniques were used to study the activity of immunocitochemically identified 5-HT DRN neurons. Administration of nicotine (1µM) in sham-operated animals produced stimulatory effects in all 5-HT DRN neurons studied. In Adx+CSR rats however, nicotine inhibited 75% of 5-HT DRN neurons and increased the potassium-dependent inward rectifying current. The inhibitory effect of nicotine upon 5-HT DRN neurons was dependent on serotonin release inside the DRN, since it was converted into a stimulatory response by the selective antagonist of 5-HT1A receptors N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridyl)cyclohexanecarboxamide (WAY100635, 25nM). Adx+CSR rats also presented an increased function of 5-HT1A autoreceptors, since, in these rats, serotonin (1-10µM) produced a higher increase in the potassium dependent inward rectifying current in comparison with sham-operated animals. Serotonin release inside DRN was mediated by α4ß2 nicotinic acetylcholine receptors since the selective antagonist of these receptors dihydro-ß-erytroidine hydrobromide (DHßE, 100nM) blocked the inhibitory effects of nicotine 5-HT DRN neurons. These data indicate that, in the experimental model of adrenalectomised rats implanted with corticosterone pellets, nicotine increases the function of 5-HT1A receptors of 5-HT DRN neurons.

CRH: the link between hormonal-, metabolic- and behavioral responses to stress.

Two major and mutually interconnected brain systems are recruited during stress reaction. One is the hypothalamic paraventricular nucleus (PVH) and the second is the extended amygdala. PVH governs the neuroendocrine stress response while CeA regulates most of the autonomic and behavioral stress reactions. The common neurohormonal mediator of these responses is the corticotropin-releasing hormone, CRH, which is expressed in both centers. CRH belongs to a larger family of neuropeptides that also includes urocortins 1, 2, and 3 all have different affinity toward the two types of CRHR receptors and have been implicated in regulation of stress and HPA axis activity. One functionally relevant aspect of CRH systems is their differential regulation by glucocorticoids. While corticosterone inhibits CRH transcription in the PVH, stress-induced glucocorticoids stimulate CRH expression in the extended amygdala. This review summarizes past and recent findings related to CRH gene regulation and its involvement in the neuroendocrine, autonomic and behavioral stress reaction.

Progress toward positive allosteric modulators of the metabotropic glutamate receptor subtype 5 (mGluR5).

This Review describes recent trends in the development of small molecule mGlu(5) positive allosteric modulators (PAMs). A large body of pharmacological, genetic, electrophysiological, and in vivo behavioral evidence has accumulated over the past decade which continues to support the hypothesis and rationale for the activation of the metabotropic glutamate receptor subtype 5 (mGlu(5)) as a viable and promising target for the development of novel antipsychotics. Until recently, functionally efficacious and potent mGlu(5) PAMs have been somewhat structurally limited in scope and slow to emerge. This Review will discuss efforts since late 2008 which have provided novel mGlu(5) PAM chemotypes, offering ligands with a diverse range of pharmacological, physicochemical, and DMPK properties that were previously unavailable. In addition, significant biological studies of importance in the past few years using the well established PAMs known as DFB, CPPHA, CDPPB, and ADX-47273 will be discussed.