PICK1, a PDZ domain-containing protein, is known to increase the reuptake activities of dopamine transporters by increasing their expressions on the cell surface. Here, we report a direct and functional interaction between PICK1 and dopamine D₃ receptors (D₃R), which act as autoreceptors to negatively regulate dopaminergic neurons. PICK1 colocalized with both dopamine D₂ receptor (D₂R) and D₃R in clusters but exerted different functional influences on them. The cell surface expression, agonist affinity, endocytosis, and signaling of D₂R were unaffected by the coexpression of PICK1. On the other hand, the surface expression and tolerance of D₃R were inhibited by the coexpression of PICK1. These findings show that PICK1 exerts multiple effects on D₃R functions.
Autoreceptors ; Dopamine Plasma Membrane Transport Proteins ; Dopamine* ; Dopaminergic Neurons ; Endocytosis ; Hand

Migraine is one of the common and frequently encountered diseases. The study proves that 5-hydroxytryptamine (5-HT) receptor, plays an important role in the occurrence of migraine. Rat striatum was used for preparation of the cell membrane stationary phase (CMSP) in our experiments. The cell membrane chromatography (CMC)-offline-HPLC system was applied to specifically recognize the components from the drug pair of Chuanxiong Rhizoma and Angelicae Dahuricae Radix, which interact with the receptors on CMSP. The dissociation equilibrium constant (KD) was measured in a rat striatum/CMC system, performed by continuously pumping sumatriptan, a 5-HT1D agonist, ranging from 2.42 x 10(-8) to 4.84 x 10(-7) mol · L(-1) through a CMC column, and the capacity factors (k') were recorded. The KD value obtained from the model was (4.59 ± 0.33) x 10(-6) mol · L(-1) for imperatorin, and the rat model of migraine induced by nitroglycerin was applied to validate the pharmacological effects of the drug pair. The results indicated that the CMC method could be a quick and efficient way for characterizing the drug-receptor interactions in vitro.
Angelica ; chemistry ; Animals ; Cell Membrane ; chemistry ; Chromatography, High Pressure Liquid ; methods ; Drug Evaluation, Preclinical ; methods ; Drugs, Chinese Herbal ; chemistry ; Male ; Migraine Disorders ; drug therapy ; Rats ; Rats, Sprague-Dawley ; Receptor, Serotonin, 5-HT1D ; chemistry ; Serotonin Receptor Agonists ; analysis

OBJECTIVETo assess whether HTR1A and HTR1B polymorphisms are associated with the predisposition, gender, PUMC Classification and/or severity of adolescent idiopathic scoliosis (AIS).

METHODSRs6294 (HTR1A) and rs6296 (HTR1B) were genotyped in 103 AIS patients treated from January 2006 to March 2007, and 108 controls with matched gender and age. The data were analyzed by the allelic and genotypic association analysis, and the genotype-phenotype (gender, PUMC Classification, and Cobb angle) association analysis.

RESULTSThe distributions of the alleles of all the 2 SNPs met Hardy-Weinberg equilibrium in the controls (goodness-of-fit chi(2) test, P > 0.05). The allele A of rs6294 was related with the occurrence of AIS (P = 0.041), but differences of the allele frequencies of rs6296 and the genotype frequencies of both SNPs between 2 groups had no statistical significance (P > 0.05). The genotype A/A + A/G of rs6294 was associated with AIS PUMC type III, and there was no other positive results in genotype-phenotype association analysis.

CONCLUSIONThese results suggest that HTR1A may be a predisposition gene of AIS PUMC type III, and PUMC Classification may has its genetic basis.

Adolescent ; Gene Frequency ; Genetic Association Studies ; Genotype ; Humans ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Receptor, Serotonin, 5-HT1A ; genetics ; Receptor, Serotonin, 5-HT1B ; genetics ; Scoliosis ; genetics

Migraine and anxiety disorders are frequently co-morbid with balance disorders. Potential mechanisms for migrainous vertigo include sites of action of 5-HT (serotonin) 1B and 1D receptor agonists such as rizatriptan, which attenuate motion sickness in migraineurs. Selective serotonin reuptake inhibitors (SSRIs) are also known to be efficacious in the treatment of vertigo. Relative distribution of the 5-HT receptor subtypes and their functional roles in the vestibular nuclei and inner ear is still unknown. Using 5-HT1A, 1B, AND 1D receptors-specific antibody, we have demonstrated a differential distribution of these receptor subtypes within the rat vestibular nuclei and inner ear. For 5-HT receptor subtypes expression in the vestibular and auditory periphery, most ganglion cells in the vestibular ganglion showed immunoreactivity for 5-HT1A, 5-HT1B and 5-HT1D receptors. In addition, 5-HT1B and 1D receptors immunopositive reactivities were associated with endothelial cells of small blood vessels in the vestibular ganglion and nerve, endothelial cells in both the spiral ligament deep to the spiral prominence and stria vascularis and endothelial cells on blood vessels along the margins of the spiral ganglion. For 5-HT receptor subtypes expression in the vestibular nuclei (VN), the 5-HT1A, 1B and 1D receptors were expressed differentially in the VN. Fine varicose axons in the periventricular plexus showed intense 5-HT1A receptor expression in the medial VN (MVN) and extended into the superior VN (SVN). By contrast, 5-HT1B receptors were not expressed the ventricular plexus axons. Rather, 5-HT1B and 1D receptors immunopositive cell bodies and neuronal processes were dense in rostral MVN, dorsal SVN, lateral VN (LVN) and ventral aspect of nucleus prepositus hypoglossi (NPH). In the present study, inner ear and vestibular nuclei showed distinct distributions of 5- HT1A, 1B and 1D receptors expressions that are parallel to their distribution in peripheral and central nociceptive pathways. These differentially distributed 5-HT receptor subtypes are potential targets to explain the efficacy of SSRIs and triptans in treating migraine and migrainous vertigo.
Animals ; Anxiety Disorders ; Axons ; Blood Vessels ; Ear, Inner ; Endothelial Cells ; Ganglion Cysts ; Migraine Disorders ; Motion Sickness ; Neurons ; Rats ; Receptor, Serotonin, 5-HT1A ; Receptor, Serotonin, 5-HT1B ; Receptor, Serotonin, 5-HT1D ; Serotonin ; Serotonin Uptake Inhibitors ; Spiral Ganglion ; Spiral Ligament of Cochlea ; Stria Vascularis ; Triazoles ; Tryptamines ; Vertigo ; Vestibular Nuclei

5-HT(1A) receptor is implicated in the pathogenesis and the therapeutic mechanism of various psychiatric disorders. Especially, the mechanism of action of selective serotonin reuptake inhibitors (SSRIs) was hypothesized that 5-HT(1A) autoreceptor desensitization plays an important role in the treatment of depression and anxiety. 5-HT(1A) receptor stimulation may also mediate the neurogenesis of prefrontal cortex and hippocampus. The 5-HT(1A) agonism has an important meaning in the treatment of schizophrenia. Most atyptical antipsychotics have the property of 5-HT(2A) antagonist, and some have that of 5-HT(1A) agonist. In the various regions of brain, 5-HT(1A) and 5-HT(2A) have the functionally antagonistic properties. Recently, 5-HT(1A) receptor-related agents have been investigated in the treatment of acute ischemic stroke and Alzheimer's disease. Therefore, the further understanding about the 5-HT(1A) receptors in the brain functions will provide the development of future drugs and the advancement of psychopharmacology.
Alzheimer Disease ; Antipsychotic Agents ; Anxiety ; Autoreceptors ; Brain ; Depression ; Drug Therapy* ; Felodipine ; Hippocampus ; Neurogenesis ; Prefrontal Cortex ; Psychopharmacology ; Receptor, Serotonin, 5-HT1A* ; Schizophrenia ; Serotonin ; Serotonin Uptake Inhibitors ; Stroke

OBJECTIVES: Recently, there has been a growing enthusiasm in biological approach to personality; the identification of genes responsible for particular personality traits. The aim of this study was to investigate the association between the 5-HT1Dbeta G861C polymorphism and personality traits. METHODS: We recruited 218 normal subjects. The Korean version of the Temperament and Character Inventory (TCI) was used to assess personality traits. From blood samples taken from the subjects, DNA was isolated using standard techniques and the HT1Dbeta G861C polymorphism was genotyped by means of polymerase chain reaction and Homogeneous MassEXTEND method. We classified the subject into the GG, CG, and GG groups according to their genotypes. The differences in the temperament factors of the TCI between homozygote group (GG+CC genotype) and heterozygote group (CG genotype) were tested. RESULTS: The heterozygote group had significantly lower Harm avoidance (HA) scores and higher Self-directedness scores (SD) than the homozygote group. CONCLUSION: In conclusion, we found some associations between the 5-HT1Dbeta G861C polymorphism and the personality dimension HA and SD in a normal population.
DNA ; Genotype ; Heterozygote ; Homozygote ; Polymerase Chain Reaction ; Receptor, Serotonin, 5-HT1B* ; Temperament

A growing body of evidence suggests that major depression is associated with increased productions of pro-inflammatory cytokines such as IL-1, IL-6, IL-12 or TNF-alpha and increased concentrations of prostaglandin E2 and negative-regulatory cytokines such as IL-4 or IL-10. In major depression, interactions among brain 5-HT levels, the activity of its autoreceptors, and that of postsynaptic receptors play a critical role in mood changes and depression. Recently, the link between cytokines and serotonergic turnover has been explored. Cytokines such as IL-1, IL-2 and IFN-gamma reduce the production of 5-HT by stimulating the activity of indoleamine-2,3 dioxygenase (IDO), an enzyme which convert tryptophan, the precursor of 5-HT to kynurenine. The kynurenine is metabolized into quinolinic acid (quinolinate) and kynurenic acid (kynurenate), an excitotoxic NMDA receptor agonist and the antagonist of three ionotropic excitotatory aminoacid receptors, respectively. The cytokineserotonin interaction through IDO that leads to the challenge between quinolinate and kynurenate in the brain may finally induce the neurodegeneration in depression. The neurodegeneration hypothesis of depression can explain how people cope with psychological or physical stress at different stages according to severity and duration of stress and why major depression develops.
Autoreceptors ; Brain ; Cytokines ; Depression* ; Dinoprostone ; Interleukin-1 ; Interleukin-10 ; Interleukin-12 ; Interleukin-2 ; Interleukin-4 ; Interleukin-6 ; Kynurenic Acid ; Kynurenine ; N-Methylaspartate ; Neurogenesis ; Quinolinic Acid ; Serotonin ; Tryptophan ; Tumor Necrosis Factor-alpha

BACKGROUND: Spinal 5-hydroxytryptamine (5-HT) has been shown to display an antinociceptive effect, which is mediated by 5-HT receptors. Previous studies have revealed the presence of at least four types of 5-HT receptors in the spinal cord. The aim of this study was to assess the role of each spinal 5-HT receptor in the antinociception of intrathecal 5-HT using the formalin test. METHODS: Rats were implanted with lumbar intrathecal catheters. After the administration of 5-HT, formalin-induced nociceptive behavior (flinching response) was observed for 60 min. To further clarify the role of the 5-HT receptors in the antinociception of 5-HT, several antagonists of 5-HT receptors were administered intrathecally 10 min before 5-HT delivery, and formalin was injected 10 min later. RESULTS: Intrathecal 5-HT dose-dependently suppressed flinching during phase 1 and 2 in the formalin test. 5-HT1B (GR 55562), 5-HT2C (N-desmethylclozapine), 5-HT3 (LY-278,584) and 5-HT4 (SDZ-205,557) receptors antagonists reversed this antinociception by 5-HT during both phases in the formalin test. 5-HT1A receptor antagonist (WAY-100635) decreased antinociception by 5-HT in phase 2, but not in phase 1. A 5-HT1D receptor antagonist (BRL 15572) did not antagonize the antinociception of 5-HT in either phases. CONCLUSIONS: Spinal 5-HT1B, 5-HT2C, 5-HT3 and 5-HT4 receptors, but not the 5-HT1D receptor, are involved in the antinociception of serotonin in the facilitated state and in the acute pain evoked by a formalin stimulus. The 5-HT1A receptor seems to play a role in 5-HT-induced antinociception in the facilitated state.
Acute Pain ; Animals ; Catheters ; Formaldehyde ; Pain Measurement ; Rats* ; Receptor, Serotonin, 5-HT1A ; Receptor, Serotonin, 5-HT1D ; Receptors, Serotonin ; Receptors, Serotonin, 5-HT4 ; Serotonin* ; Spinal Cord*

Amisulpride, a substituted benzamide derivative, is a newer atypical antipsychotics. It mainly blocks presynaptic dopamine D2/D3 autoreceptors which is preferentially located in prefrontal area and blocks postsynaptic dopamine D2/D3 receptors in the limbic system. By these mechanism, amisulpride can improve both negative and positive symptoms. In addition to these action, its property of fast dissociation (Koff) and selectivity to D2/D3 receptors can explain more favorable side effects profiles. A lot of studies showed that amisulpride has equivalent or better efficacy and safety to other atypical antipsychotics. Meta-analysis studies is very informative because it contains many cases of previous studies. So we reviewed some meta-analysis studies which compared amisulpride with placebo or other antipsychotics. On positive symptoms of acute schizophrenia, the most pooled analyses of amisulpride have shown to be equally effective with conventional antispychotics. One meta-analysis study have shown that amisulpride is more effective than conventional drugs. On primary negative symptoms, amisulpride is only agents which is investigated for the efficacy in patients with predominantly negative symptoms. as a results of meta-analysis, amisulpride was shown to be more effective than placebo in primary negative symptoms and have a trend of superiority to conventional agents. The safety and tolerability of amisulpride was equal to or better than other atypical drugs on pooled analysis. The drop out rate was also more favorable than conventional antipsychotics. In Summary, amisulpride showed efficacy similar to that of other atypical antipsychotics in reducing positive symptoms. Moreover, its better properties for negative and affective symptoms, and favorable side effects profiles provides another alternative for treatment of schizophrenia. These results show that amisulpride is a favorable `atypical' antipsychotics, and that 5-HT2/D2 antagonism is not only mechanism of `atypicality'.
Affective Symptoms ; Antipsychotic Agents ; Autoreceptors ; Dopamine ; Humans ; Limbic System ; Meta-Analysis as Topic ; Schizophrenia

A variety of G protein coupled receptors (GPCRs) are expressed in the presynaptic terminals of central and peripheral synapses and play regulatory roles in transmitter release. The patch-clamp whole-cell recording technique, applied to the calyx of Held presynaptic terminal in brainstem slices of rodents, has made it possible to directly examine intracellular mechanisms underlying the GPCR-mediated presynaptic inhibition. At the calyx of Held, bath-application of agonists for GPCRs such as GABAB receptors, group III metabotropic glutamate receptors (mGluRs), adenosine A1 receptors, or adrenaline alpha2 receptors, attenuate evoked transmitter release via inhibiting voltage-activated Ca2+ currents without affecting voltage-activated K+ currents or inwardly rectifying K+ currents. Furthermore, inhibition of voltage-activated Ca2+ currents fully explains the magnitude of GPCR-mediated presynaptic inhibition, indicating no essential involvement of exocytotic mechanisms in the downstream of Ca2+ influx. Direct loadings of G protein beta gamma subunit (G beta gamma) into the calyceal terminal mimic and occlude the inhibitory effect of a GPCR agonist on presynaptic Ca2+ currents (IpCa), suggesting that G beta gammamediates presynaptic inhibition by GPCRs. Among presynaptic GPCRs glutamate and adenosine autoreceptors play regulatory roles in transmitter release during early postnatal period when the release probability (p) is high, but these functions are lost concomitantly with a decrease in p during postnatal development.
Adenosine ; Autoreceptors ; Brain Stem ; Epinephrine ; Glutamic Acid ; GTP-Binding Proteins* ; Patch-Clamp Techniques ; Presynaptic Terminals ; Receptor, Adenosine A1 ; Receptors, G-Protein-Coupled* ; Receptors, Metabotropic Glutamate ; Rodentia ; Synapses