5-HT6 receptor antagonists. Design, synthesis, and structure-activity relationship of substituted 2-(1-methyl-4-piperazinyl)pyridines.

In this study, we present the discovery and pharmacological characterization of a new series of 6-piperazinyl-7-azaindoles. These compounds demonstrate potent antagonism and selectivity against the 5-HT6 receptor. Our research primarily focuses on optimizing the lead structure and investigating the structure-activity relationship (SAR) of these compounds. Our main objective is to improve their activity and selectivity against off-target receptors. Overall, our findings contribute to the advancement of novel compounds targeting the 5-HT6 receptor. Compound 29 exhibits significant promise in terms of pharmacological, physicochemical, and ADME (Absorption, Distribution, Metabolism, and Excretion) properties. Consequently, it merits thorough exploration as a potential drug candidate due to its favorable activity profile and successful outcomes in a range of in vivo experiments.

Development of an in vitro aggregation assay for long synthetic polypeptide, amyloidogenic gelsolin fragment AGelD187N 173-242.

Aggregation of the gelsolin protein fragment is the hallmark of the hereditary systemic disease gelsolin amyloidosis. As with other protein misfolding diseases, there is an urgent need for efficient disease-modifying treatment for gelsolin amyloidosis. The formation of amyloids can be reproduced by incubating the disease-causing amyloidogenic 8 kDa polypeptide, 70-residue gelsolin protein fragment, AGelD187N 173-242, in vitro and monitoring the process by thioflavin T dye. However, for screening of potential aggregation inhibitors, the required protein amounts are large and the biotechnological production of amyloidogenic proteins has many challenges. Conversely, use of shorter synthetic regions of AGelD187N 173-242 does not mimic the in vivo aggregation kinetics of full-length fragment as they have different aggregation propensity. In this study, we present an in vitro aggregation assay for full-length AGelD187N 173-242 that has been produced by solid-phase chemical synthesis and after that monomerized carefully. Chemical synthesis allows us to produce high quantities of full-length fragment efficiently and at low cost. We demonstrate that the generated aggregates are fibrillar in nature and how the purity, terminal modification, initial aggregates and seeding affect the aggregation kinetics of a synthetic gelsolin fragment. We also present sufficient quality criteria for the initial monomerized synthetic polypeptide.

Feasibility and patient acceptability of a commercially available wearable and a smart phone application in identification of motor states in parkinson's disease.

In the quantification of symptoms of Parkinson's disease (PD), healthcare professional assessments, patient reported outcomes (PRO), and medical device grade wearables are currently used. Recently, also commercially available smartphones and wearable devices have been actively researched in the detection of PD symptoms. The continuous, longitudinal, and automated detection of motor and especially non-motor symptoms with these devices is still a challenge that requires more research. The data collected from everyday life can be noisy and frequently contains artefacts, and novel detection methods and algorithms are therefore needed. 42 PD patients and 23 control subjects were monitored with Garmin Vivosmart 4 wearable device and asked to fill a symptom and medication diary with a mobile application, at home, for about four weeks. Subsequent analyses are based on continuous accelerometer data from the device. Accelerometer data from the Levodopa Response Study (MJFFd) were reanalyzed, with symptoms quantified with linear spectral models trained on expert evaluations present in the data. Variational autoencoders (VAE) were trained on both our study accelerometer data and on MJFFd to detect movement states (e.g., walking, standing). A total of 7590 self-reported symptoms were recorded during the study. 88.9% (32/36) of PD patients, 80.0% (4/5) of DBS PD patients and 95.5% (21/22) of control subjects reported that using the wearable device was very easy or easy. Recording a symptom at the time of the event was assessed as very easy or easy by 70.1% (29/41) of subjects with PD. Aggregated spectrograms of the collected accelerometer data show relative attenuation of low (<5Hz) frequencies in patients. Similar spectral patterns also separate symptom periods from immediately adjacent non-symptomatic periods. Discriminative power of linear models to separate symptoms from adjacent periods is weak, but aggregates show partial separability of patients vs. controls. The analysis reveals differential symptom detectability across movement tasks, motivating the third part of the study. VAEs trained on either dataset produced embedding from which movement states in MJFFd could be predicted. A VAE model was able to detect the movement states. Thus, a pre-detection of these states with a VAE from accelerometer data with good S/N ratio, and subsequent quantification of PD symptoms is a feasible strategy. The usability of the data collection method is important to enable the collection of self-reported symptom data by PD patients. Finally, the usability of the data collection method is important to enable the collection of self-reported symptom data by PD patients.

Tasipimidine-the pharmacological profile of a novel orally active selective α2A-adrenoceptor agonist.

The pharmacological profile of tasipimidine, a novel orally active α2-adrenoceptor agonist developed for situational anxiety and fear in dogs, was studied in various in vitro and in vivo models. In the cell assays, tasipimidine demonstrated binding affinity and full agonism on the human α2A-adrenoceptors with a pEC50 of 7.57, while agonism on the α2B-and α2C-adrenoceptors and the rodent α2D-adrenoceptor was weaker, resulting in pEC50 values of 6.00, 6.29 and 6.56, respectively. Tasipimidine had a low binding affinity on the human α1-adrenoceptors. It had no functional effects in the LNCaP cells expressing endogenously the human α1A-adrenoceptors but was a weak agonist in the Chem-1 cells coexpressing Gα15 protein and α1A-adrenoceptors. In the recombinant CHO cells, although tasipimidine was a weak partial agonist in the inositol monophosphate accumulation assay, it was a full agonist in the intracellular [Ca2+] assay. No functional effects were observed on the human α1B-adrenoceptor, whereas in the rat α1A and α1B-adrenoceptors, tasipimidine was a weak partial agonist. In the rat vas deferens preparations, tasipimidine was a full agonist on the α2D-adrenoceptor but weak partial agonist on the α1-adrenoceptor. The receptor profile of tasipimidine indicated few secondary targets, and no functional effects were observed. Sedative effects of tasipimidine were demonstrated in vivo by the reduced acoustic startle reflex in rats with subcutaneous doses and decreased spontaneous locomotor activity in mice with subcutaneous and higher oral doses. It may be concluded that tasipimidine is an orally active and selective α2A-adrenoceptor agonist.

Effects of fadolmidine, an α2 -adrenoceptor agonist, as an adjuvant to spinal bupivacaine on antinociception and motor function in rats and dogs.

α2 -Adrenoceptor agonists such as clonidine and dexmedetomidine are used as adjuvants to local anesthetics in regional anesthesia. Fadolmidine is an α2 -adrenoceptor agonist developed especially as a spinal analgesic. The current studies investigate the effects of intrathecally administered fadolmidine with a local anesthetic, bupivacaine, on antinociception and motor block in conscious rats and dogs. The antinociceptive effects of intrathecal fadolmidine and bupivacaine alone or in combination were tested in the rat tail-flick and the dog's skin twitch models. The durations of motor block in rats and in dogs were also assessed. In addition, the effects on sedation, mean arterial blood pressure, heart rate, respiratory rate and body temperature were evaluated in telemetrized dogs. Concentrations of fadolmidine in plasma and spinal cord were determined after intrathecal and intravenous administration in rats. Co-administration of intrathecal fadolmidine with bupivacaine increased the magnitude and duration of the antinociceptive effects and prolonged motor block without hypotension. The interaction of the antinociceptive effect was synergistic in its nature in rats. Concentration of fadolmidine in plasma was very low after intrathecal dosing. Taken together, these studies show that fadolmidine as an adjuvant to intrathecal bupivacaine provides enhanced sensory-motor block and enables a reduction of the doses of both drugs. The results indicate that co-administration of fadolmidine with intrathecal bupivacaine was able to achieve an enhanced antinociceptive effect without hypotension and could thus represent a suitable combination for spinal anesthesia.

Fadolmidine - Favourable adverse effects profile for spinal analgesia suggested by in vitro and in vivo models.

Fadolmidine is an α2-adrenoceptor full agonist developed for spinal analgesia with a local mode of action. The purpose of this study was to demonstrate the safety of fadolmidine on known α2-adrenoceptor-related effects: kidney function, urodynamics and cardiovascular variables. Furthermore, the binding affinity of fadolmidine for the 5-HT3 receptor prompted functional studies on 5-HT3. According to the binding affinity data, fadolmidine demonstrated partial agonism on the 5-HT3 receptor in transfected cells and in guinea pig ileum preparation. However, intravenous (IV) fadolmidine did not produce any 5-HT3-related hemodynamic effects in anaesthetised rats. In urodynamic studies, intrathecal (IT) fadolmidine interrupted volume-evoked voiding cycles and induced overflow incontinence at high concentrations in anaesthetised rats; however, at the analgesic dose range, the effects were mild. The effects of fadolmidine on kidney function were studied in conscious rats after IV and IT dosing. While IT fadolmidine increased dose-dependent urine output, sodium ion concentration, IV doses increased only sodium ion concentration The effects of IT fadolmidine on heart rate (HR), mean arterial pressure (MAP) and sedation were evaluated in the home cage and in the open field using a telemetry system. In resting conditions, fadolmidine decreased HR dose-dependently and increased initial MAP, whereas in actively moving rats, there were no effects at analgesic doses. The results suggest that at anticipated analgesic clinical doses, IT fadolmidine provides analgesia without significant adverse effects on sedation, MAP or HR and with only modest effects on kidney function and urodynamics.

Neurophysiology and genetics of burning mouth syndrome.

BACKGROUND AND AIMS: Neuropathic mechanisms are involved in burning mouth syndrome (BMS), and variation of the dopamine D2 receptor (DRD2) gene contributes to experimental pain perception. We investigated whether neurophysiologic findings differ in BMS patients compared to healthy controls, and whether 957C>T polymorphism of the DRD2 gene influences thermal sensitivity or pain experience in BMS. METHODS: Forty-five BMS patients (43 women), mean age 62.5 years, and 32 healthy controls (30 women), mean age 64.8 years, participated. Patients estimated pain intensity, interference, suffering and sleep with Numeric Rating Scale. Blink reflex tests of the supraorbital (SON), mental (MN) and lingual (LN) nerves, and thermal quantitative sensory testing were done. The results were analysed with ANOVA. DRD2 gene 957C>T polymorphism was determined in 31 patients, and its effects on neurophysiologic and clinical variables were analysed. RESULTS: Cool (p = 0.0090) and warm detection thresholds (p = 0.0229) of the tongue were higher in BMS patients than controls. The stimulation threshold for SON BR was higher in patients than in controls (p = 0.0056). The latencies of R2 component were longer in BMS patients than in controls (p = 0.0005) at the SON distribution. Habituation of SON BR did not differ between the groups. The heat pain thresholds were highest (p = 0.0312) in homozygous patients with 957TT, who also reported most interference (p = 0.0352) and greatest suffering (p = 0.0341). Genotype 957CC associated with sleep disturbances (p = 0.0254). CONCLUSIONS: Burning mouth syndrome patients showed thermal hypoesthesia within LN distribution compatible with small fibre neuropathy. The DRD2 957C>T genotype influences perception and experience of BMS pain. SIGNIFICANCE: The results confirm earlier findings of neuropathic pain in BMS. The DRD2 957 C>T genotype influences perception and experience of clinical pain in BMS.

Neuropeptide Y Overexpressing Female and Male Mice Show Divergent Metabolic but Not Gut Microbial Responses to Prenatal Metformin Exposure.

BACKGROUND: Prenatal metformin exposure has been shown to improve the metabolic outcome in the offspring of high fat diet fed dams. However, if this is evident also in a genetic model of obesity and whether gut microbiota has a role, is not known. METHODS: The metabolic effects of prenatal metformin exposure were investigated in a genetic model of obesity, mice overexpressing neuropeptide Y in the sympathetic nervous system and in brain noradrenergic neurons (OE-NPYDßH). Metformin was given for 18 days to the mated female mice. Body weight, body composition, glucose tolerance and serum parameters of the offspring were investigated on regular diet from weaning and sequentially on western diet (at the age of 5-7 months). Gut microbiota composition was analysed by 16S rRNA sequencing at 10-11 weeks. RESULTS: In the male offspring, metformin exposure inhibited weight gain. Moreover, weight of white fat depots and serum insulin and lipids tended to be lower at 7 months. In contrast, in the female offspring, metformin exposure impaired glucose tolerance at 3 months, and subsequently increased body weight gain, fat mass and serum cholesterol. In the gut microbiota, a decline in Erysipelotrichaceae and Odoribacter was detected in the metformin exposed offspring. Furthermore, the abundance of Sutterella tended to be decreased and Parabacteroides increased. Gut microbiota composition of the metformin exposed male offspring correlated to their metabolic phenotype. CONCLUSION: Prenatal metformin exposure caused divergent metabolic phenotypes in the female and male offspring. Nevertheless, gut microbiota of metformin exposed offspring was similarly modified in both genders.

1-Sulfonyl-6-Piperazinyl-7-Azaindoles as potent and pseudo-selective 5-HT6 receptor antagonists.

A series of 1-Sulfonyl-6-Piperazinyl-7-Azaindoles, showing strong antagonistic activity to 5-HT6 receptor (5-HT6R) was synthesized and characterized. The series was optimized to reduce activity on D2 receptor. Based on the selectivity against this off-target and the analysis of the ADME-tox profile, compound 1c was selected for in vivo efficacy assessment, which demonstrated procognitive effects as shown in reversal of scopolamine induced amnesia in an elevated plus maze test in mice. Compound 3, the demethylated version of compound 1c, was profiled against a panel of 106 receptors, channels and transporters, indicating only D3 receptor as a major off-target. Compound 3 has been selected for this study over compound 1c because of the higher 5-HT6R/D2R binding ratio. These results have defined a new direction for the design of our pseudo-selective 5-HT6R antagonists.

Novel delivery systems for improving the clinical use of peptides.

Peptides have long been recognized as a promising group of therapeutic substances to treat various diseases. Delivery systems for peptides have been under development since the discovery of insulin for the treatment of diabetes. The challenge of using peptides as drugs arises from their poor bioavailability resulting from the low permeability of biological membranes and their instability. Currently, subcutaneous injection is clinically the most common administration route for peptides. This route is cost-effective and suitable for self-administration, and the development of appropriate dosing equipment has made performing the repeated injections relatively easy; however, only few clinical subcutaneous peptide delivery systems provide sustained peptide release. As a result, frequent injections are needed, which may cause discomfort and additional risks resulting from a poor administration technique. Controlled peptide delivery systems, able to provide required therapeutic plasma concentrations over an extended period, are needed to increase peptide safety and patient compliancy. In this review, we summarize the current peptidergic drugs, future developments, and parenteral peptide delivery systems. Special emphasis is given to porous silicon, a novel material in peptide delivery. Biodegradable and biocompatible porous silicon possesses some unique properties, such as the ability to carry exceptional high peptide payloads and to modify peptide release extensively. We have successfully developed porous silicon as a carrier material for improved parenteral peptide delivery. Nanotechnology, with its different delivery systems, will enable better use of peptides in several therapeutic applications in the near future.

Right secondary somatosensory cortex-a promising novel target for the treatment of drug-resistant neuropathic orofacial pain with repetitive transcranial magnetic stimulation.

High-frequency repetitive transcranial magnetic stimulation (rTMS) of the motor cortex has analgesic effect; however, the efficacy of other cortical targets and the mode of action remain unclear. We examined the effects of rTMS in neuropathic orofacial pain, and compared 2 cortical targets against placebo. Furthermore, as dopaminergic mechanisms modulate pain responses, we assessed the influence of the functional DRD2 gene polymorphism (957C>T) and the catechol-O-methyltransferase (COMT) Val158Met polymorphism on the analgesic effect of rTMS. Sixteen patients with chronic drug-resistant neuropathic orofacial pain participated in this randomized, placebo-controlled, crossover study. Navigated high-frequency rTMS was given to the sensorimotor (S1/M1) and the right secondary somatosensory (S2) cortices. All subjects were genotyped for the DRD2 957C>T and COMT Val158Met polymorphisms. Pain, mood, and quality of life were monitored throughout the study. The numerical rating scale pain scores were significantly lower after the S2 stimulation than after the S1/M1 (P = 0.0071) or the sham (P = 0.0187) stimulations. The Brief Pain Inventory scores were also lower 3 to 5 days after the S2 stimulation than those at pretreatment baseline (P = 0.0127 for the intensity of pain and P = 0.0074 for the interference of pain) or after the S1/M1 (P = 0.001 and P = 0.0001) and sham (P = 0.0491 and P = 0.0359) stimulations. No correlations were found between the genetic polymorphisms and the analgesic effect in the present small clinical sample. The right S2 cortex is a promising new target for the treatment of neuropathic orofacial pain with high-frequency rTMS.

Prenatal metformin exposure in a maternal high fat diet mouse model alters the transcriptome and modifies the metabolic responses of the offspring.

AIMS: Despite the wide use of metformin in metabolically challenged pregnancies, the long-term effects on the metabolism of the offspring are not known. We studied the long-term effects of prenatal metformin exposure during metabolically challenged pregnancy in mice. MATERIALS AND METHODS: Female mice were on a high fat diet (HFD) prior to and during the gestation. Metformin was administered during gestation from E0.5 to E17.5. Male and female offspring were weaned to a regular diet (RD) and subjected to HFD at adulthood (10-11 weeks). Body weight and several metabolic parameters (e.g. body composition and glucose tolerance) were measured during the study. Microarray and subsequent pathway analyses on the liver and subcutaneous adipose tissue of the male offspring were performed at postnatal day 4 in a separate experiment. RESULTS: Prenatal metformin exposure changed the offspring's response to HFD. Metformin exposed offspring gained less body weight and adipose tissue during the HFD phase. Additionally, prenatal metformin exposure prevented HFD-induced impairment in glucose tolerance. Microarray and annotation analyses revealed metformin-induced changes in several metabolic pathways from which electron transport chain (ETC) was prominently affected both in the neonatal liver and adipose tissue. CONCLUSION: This study shows the beneficial effects of prenatal metformin exposure on the offspring's glucose tolerance and fat mass accumulation during HFD. The transcriptome data obtained at neonatal age indicates major effects on the genes involved in mitochondrial ATP production and adipocyte differentiation suggesting the mechanistic routes to improved metabolic phenotype at adulthood.

Variation in the dopamine D2 receptor gene plays a key role in human pain and its modulation by transcranial magnetic stimulation.

We tested whether variation of the dopamine D2 receptor (DRD2) gene contributes to individual differences in thermal pain sensitivity and analgesic efficacy of repetitive transcranial magnetic stimulation (rTMS) in healthy subjects (n=29) or susceptibility to neuropathic pain in patients with neurophysiologically confirmed diagnosis (n=16). Thermal sensitivity of healthy subjects was assessed before and after navigated rTMS provided to the S1/M1 cortex. All subjects were genotyped for the DRD2 gene 957C>T and catechol-O-methyltransferase (COMT) protein Val158Met polymorphisms. In healthy subjects, 957C>T influenced both innocuous and noxious thermal detection thresholds that were lowest in 957TT homozygotes (P values from .0277 to .0462). rTMS to S1 cortex had analgesic effect only in 957TT homozygote genotype (P=.0086). In patients, prevalence of 957TT homozygote genotype was higher than in a healthy Finnish population (50% vs 27%; P=.0191). Patients with 957TT genotype reported more severe pain than patients with other genotypes (P=.0351). COMT Val158Met polymorphism was not independently associated with the studied variables. Genetic regulation of DRD2 function by 957C>T polymorphism thus seems to influence thermal and pain sensitivity, its modulation by rTMS, and susceptibility to neuropathic pain. This indicates a central role for the dopamine system and DRD2 in pain and analgesia. This may have clinical implications regarding individualized selection of patients for rTMS treatment and assessment of risks for neuropathic pain.

Association between Neurocognitive Impairment and the Short Allele of the 5-HTT Promoter Polymorphism in Depression: A Pilot Study.

Depression has been shown to be associated with cognitive deficits in various cognitive domains. However, it is still unclear which factors contribute to cognitive impairment. The objective of this study was to find out whether a functional polymorphism in the promoter region of the serotonin transporter (5-HTTLPR) gene is associated with the impairment of cognitive functioning among depressed patients. In a pilot study, a sample of 19 patients with major depressive disorder (MDD) and 19 healthy controls was investigated with an extensive psychiatric and neuropsychological examination. All participants were genotyped for 5-HTTLPR. Depressed patients with the short allele of the 5-HTT promoter region exhibited inferior cognitive performance compared to patients with the long allele polymorphism. In healthy controls, no association between genotype and cognitive performance was found. The result suggests that in MDD patients with the short allele of the 5-HTTLPR polymorphism the vulnerability to cognitive impairment is increased compared to MDD patients without the short allele inheritance. These preliminary findings need to be confirmed in a larger cohort of MDD patients.

Prenatal metformin exposure in mice programs the metabolic phenotype of the offspring during a high fat diet at adulthood.

AIMS: The antidiabetic drug metformin is currently used prior and during pregnancy for polycystic ovary syndrome, as well as during gestational diabetes mellitus. We investigated the effects of prenatal metformin exposure on the metabolic phenotype of the offspring during adulthood in mice. METHODS: Metformin (300 mg/kg) or vehicle was administered orally to dams on regular diet from the embryonic day E0.5 to E17.5. Gene expression profiles in liver and brain were analysed from 4-day old offspring by microarray. Body weight development and several metabolic parameters of offspring were monitored both during regular diet (RD-phase) and high fat diet (HFD-phase). At the end of the study, two doses of metformin or vehicle were given acutely to mice at the age of 20 weeks, and Insig-1 and GLUT4 mRNA expressions in liver and fat tissue were analysed using qRT-PCR. RESULTS: Metformin exposed fetuses were lighter at E18.5. There was no effect of metformin on the maternal body weight development or food intake. Metformin exposed offspring gained more body weight and mesenteric fat during the HFD-phase. The male offspring also had impaired glucose tolerance and elevated fasting glucose during the HFD-phase. Moreover, the expression of GLUT4 mRNA was down-regulated in epididymal fat in male offspring prenatally exposed to metformin. Based on the microarray and subsequent qRT-PCR analyses, the expression of Insig-1 was changed in the liver of neonatal mice exposed to metformin prenatally. Furthermore, metformin up-regulated the expression of Insig-1 later in development. Gene set enrichment analysis based on preliminary microarray data identified several differentially enriched pathways both in control and metformin exposed mice. CONCLUSIONS: The present study shows that prenatal metformin exposure causes long-term programming effects on the metabolic phenotype during high fat diet in mice. This should be taken into consideration when using metformin as a therapeutic agent during pregnancy.

Influence of serotonin transporter gene polymorphism (5-HTTLPR polymorphism) on the relation between brain 5-HT transporter binding and heart rate corrected cardiac repolarization interval.

OBJECTIVE: Serotonin transporter gene polymorphism (5-HTTLPR polymorphism) predicts the degree of structural and functional connectivity in the brain, and less consistently the degree of vulnerability for anxiety and depressive disorders. It is less known how 5-HTTLPR polymorphism influences on the coupling between brain and neuronal cardiovascular control. The present study demonstrates the impact of 5-HTTLPR polymorphism on the relations between heart rate (HR) corrected cardiac repolarization interval (QTc interval) and the brain 5-HTT binding. MATERIAL AND METHODS: Thirty healthy young adults (fifteen monozygotic twin pairs) (mean age 26±1.3 years, 16 females) were imagined with single-photon emission computed tomography (SPECT) using iodine-123 labeled 2ß-carbomethoxy-3ß-(4-iodophenyl) nortropane (nor-ß-CIT). Continuous ECG recording was obtained from each participant at supine rest. Signal averaged QTc interval on continuous ECG was calculated and compared with the brain imaging results. RESULTS: In the two groups [l homozygotes (n = 16, 10 females), s carriers (n = 14, 8 female)] HR and the length of QTc interval were not influenced by 5-HTTLPR polymorphism. There were no significant relations between HR and 5-HTT binding in the brain. There were significant associations between QTc interval and nor-ß-CIT binding in the brain in l homozygotes, but not in s carriers (correlations for QTc interval and nor-ß-CIT binding of striatum, thalamus and right temporal region were -0.8--0.9, (p<0.0005), respectively). CONCLUSION: The finding of longer QTc interval with less 5-HTT binding availability in major serotonergic binding sites in l homozygotes, but not in s carriers, implicate to differentiated control of QTc interval by 5-HTTLPR polymorphism.

Striatal µ-opioid receptor availability predicts cold pressor pain threshold in healthy human subjects.

Previous PET studies in healthy humans have shown that brain µ-opioid receptor activation during experimental pain is associated with reductions in the sensory and affective ratings of the individual pain experience. The aim of this study was to find out whether brain µ-opioid receptor binding at the resting state, in absence of painful stimulation, can be a long-term predictor of experimental pain sensitivity. We measured µ-opioid receptor binding potential (BP(ND)) with µ-opioid receptor selective radiotracer [(11)C]carfentanil and positron emission tomography (PET) in 12 healthy male subjects. Later, we recruited these subjects to participate in a separate psychophysical testing session to measure cold pressor pain threshold, cold pressor pain tolerance and tactile sensitivity with von Frey monofilaments. We used both voxel-by-voxel and region-of-interest image analyses to examine the potential associations between µ-opioid receptor BP(ND) and psychophysical measures. The results show that striatal µ-opioid receptor BP(ND) predicts cold pressor pain threshold, but not cold pressor pain tolerance or tactile sensitivity. This finding suggests that striatal µ-opioid receptor density is involved in setting individual pain threshold.

Association of the leucine-7 to proline-7 variation in the signal sequence of neuropeptide Y with major depression.

OBJECTIVE: There is clear evidence of a genetic component in major depression, and several studies indicate that neuropeptide Y (NPY) could play an important role in the pathophysiology of the disease. A well-known polymorphism encoding the substitution of leucine to proline in the signal peptide sequence of NPY (Leu7Pro variation) was previously found to protect against depression. Our study aimed at replicating this association in a large Danish population with major depression. METHOD: Leu7Pro was studied in a sample of depressed patients and ethnically matched controls, as well as psychiatric disease controls with schizophrenia. Possible functional consequences of Leu7Pro were explored in vitro. RESULTS: In contrast to previous studies, Pro7 appeared to be a risk allele for depression, being significantly more frequent in the depression sample (5.5%, n = 593; p = 0.009; odds ratio, OR: 1.46) as compared to ethnically matched controls (3.8%, n = 2912), while schizophrenia patients (4.1%, n = 503) did not differ. In vitro, the Pro7 substitution appeared to be associated with reduced levels of NPY without affecting its mRNA level. CONCLUSION: The Leu7Pro variation may increase the risk of major depression, possibly by affecting the biosynthesis of NPY.

Neuropeptide Y in the noradrenergic neurons induces the development of cardiometabolic diseases in a transgenic mouse model.

Neuropeptide Y (NPY) is a neuropeptide widely expressed in the brain and a peptide transmitter of sympathetic nervous system (SNS) co-released with noradrenaline (NA) in prolonged stress. Association of a gain-of-function polymorphism in the human NPY gene with dyslipideamia, diabetes and vascular diseases suggests that increased NPY plays a role in the pathogenesis of the metabolic syndrome in humans. In the hypothalamus, NPY plays an established role in the regulation of body energy homeostasis. However, the effects of NPY elsewhere in the brain and in the SNS are less explored. In order to understand the role of NPY co-expressed with NA in the sympathetic nerves and brain noradrenergic neurons, a novel mouse model overexpressing NPY in noradrenergic neurons was generated. The mouse displays metabolic defects such as increased adiposity, hepatosteatosis, and impaired glucose tolerance as well as stress-related hypertension and increased susceptibility to vascular wall hypertrophy. The mouse phenotype closely reflects the findings of the several association studies with human NPY gene polymorphisms, and fits with the previous work on the effects of stress-induced NPY release on metabolism and vasculature. Thus, in addition of promoting feeding and obesity in the hypothalamus, NPY expressed in the noradrenergic neurons in the brain and in the SNS induces the development of cardiometabolic diseases.

Serotonin-transporter-linked promoter region polymorphism and serotonin transporter binding in drug-naïve patients with major depression.

AIMS: Both the serotonin transporter and its genetic regulation by the serotonin-transporter-linked polymorphic region have a role in the pathophysiology of depression. Most of the previous studies have found no influence of serotonin-transporter-linked polymorphic region allelic variation on serotonin transporter binding in healthy controls or patients with major depression. Due to the inconsistency of the previous findings, we compared single photon emission computed tomography imaging with the serotonin-transporter-linked polymorphic region genotype in patients with major depressive disorder. METHODS: A total of 23 drug-naïve patients with major depressive disorder were genotyped and brain imaged with ([123I])nor-beta-CIT single photon emission computed tomography. The severity of depression was evaluated with the 17-item Hamilton depression rating scale. RESULTS: Depressed patients homozygous for the short allele had lower ([123I])nor-beta-CIT binding in the medial prefrontal cortex, but not in the midbrain, compared with the other genotypes. CONCLUSION: The decreased medial prefrontal cortical serotonin transporter binding in the patients homozygous for the short allele may be linked to altered function of the serotonin-transporter-linked polymorphic region gene expressed in these patients, especially in the medial prefrontal cortex.