No abstract available.
Dementia ; Indans ; Lewy Bodies ; Piperidines ; Receptors, sigma

OBJECTIVE: The purpose of this study was to investigate the effects of haloperidol on [Ca2+]i in hamster insulinoma cells (HIT T-15). METHODS: [Ca2+]i levels were measured by calcium imaging techniques, and membrane potential ionic currents were recorded using conventional patch-clamp methods. RESULTS: Haloperidol induced a transient [Ca2+]i increase, which was abolished by the removal of extracellular Ca2+ or pretreatment with Ca2+ channel blockers (nimodipine and mibefradil). Haloperidol depolarized the membrane potential and inhibited the ATP-sensitive K+ (KATP) channels. Sigma receptor agonists, (+)-SKF10047 and ifenprodil, induced a transient [Ca2+]i increase similar to haloperidol. BD1047, a sigma receptor antagonist, completely blocked the [Ca2+]i increase induced by haloperidol. Haloperidol inhibited the KCl-induced [Ca2+]i increase and voltage-dependent Ca2+ currents. Sigma receptor agonists [(+)-SKF10047, ifenprodil] also inhibited the KCl-induced [Ca2+]i increase. CONCLUSION: Our results suggest that haloperidol induces depolarization, which increases [Ca2+]i by voltage-gated Ca2+ currents via the closing of KATP channels. Haloperidol also inhibits KCl-induced [Ca2+]i increases in the same manner. These effects of haloperidol seemed to be mediated by sigma receptors, which might be linked to the pathogenesis of haloperidol-induced diabetes mellitus.
Animals ; Calcium ; Cricetinae ; Diabetes Mellitus ; Haloperidol* ; Insulinoma* ; KATP Channels ; Membrane Potentials ; Receptors, sigma

Intracranial headaches, including migraines, are mediated by nociceptive activation of the trigeminal nucleus caudalis (TNC), but the precise mechanisms are poorly understood. We previously demonstrated that selective blockage of spinal sigma-1 receptors (Sig-1R) produces a prominent antinociceptive effect in several types of pain models. This study evaluates whether the Sig-1R antagonist (BD1047) has an antinociceptive effect on capsaicin (a potent C-fiber activator) induced headache models in rats. Intracisternal infusion of capsaicin evoked pain behavior (face grooming), which was significantly attenuated by BD1047 pretreatment. BD1047 consistently reduced capsaicin-induced Fos-like immunoreactivity (Fos-LI), a neuronal activator, in the TNC in a dose-dependent manner. Moreover, capsaicin-induced phosphorylation of N-methyl-D-aspartate receptor subunit 1 was reversed by BD1047 pretreatment in the TNC. These results indicate that the Sig-1R antagonist has an inhibitory effect on nociceptive activation of the TNC in the capsaicin-induced headache animal model.
Animals ; Capsaicin ; Headache ; Migraine Disorders ; Models, Animal ; N-Methylaspartate ; Neurons ; Phosphorylation ; Rats ; Receptors, sigma ; Trigeminal Nuclei

Cytosol ; metabolism ; DNA-(Apurinic or Apyrimidinic Site) Lyase ; metabolism ; Endoplasmic Reticulum ; metabolism ; Humans ; Receptors, sigma ; metabolism

Rabbit Syndrome is an uncommon side effect of antipsychotic treatment. Although it is usually associated with typical antipsychotics, it can also be related to atypical antipsychotics. Anticholinergics are the most accepted treatment approach in treating Rabbit Syndrome. Fluvoxamine is a member of selective serotonin reuptake inhibitors and it is a potent agonist of sigma 1 receptors. In this article, we report a Rabbit Syndrome case who has benefited from fluvoxamine, in terms of both depressive disorder and Rabbit Syndrome; and present the data on the effects of sigma 1 agonist fluvoxamine on numerous movement disorders.
Antipsychotic Agents ; Cholinergic Antagonists ; Depressive Disorder ; Fluvoxamine ; Movement Disorders ; Receptors, sigma ; Serotonin Uptake Inhibitors

Human salivary histatin 1 (Hst1) exhibits a series of cell-activating properties, such as promoting cell spreading, migration, and metabolic activity. We recently have shown that fluorescently labeled Hst1 (F-Hst1) targets and activates mitochondria, presenting an important molecular mechanism. However, its regulating signaling pathways remain to be elucidated. We investigated the influence of specific inhibitors of G protein-coupled receptors (GPCR), endocytosis pathways, extracellular signal-regulated kinases 1/2 (ERK1/2) signaling, p38 signaling, mitochondrial respiration and Na+/K+-ATPase activity on the uptake, mitochondria-targeting and -activating properties of F-Hst1. We performed a siRNA knockdown (KD) to assess the effect of Sigma-2 receptor (S2R) /Transmembrane Protein 97 (TMEM97)-a recently identified target protein of Hst1. We also adopted live cell imaging to monitor the whole intracellular trafficking process of F-Hst1. Our results showed that the inhibition of cellular respiration hindered the internalization of F-Hst1. The inhibitors of GPCR, ERK1/2, phagocytosis, and clathrin-mediated endocytosis (CME) as well as siRNA KD of S2R/TMEM97 significantly reduced the uptake, which was accompanied by the nullification of the promoting effect of F-Hst1 on cell metabolic activity. Only the inhibitor of CME and KD of S2R/TMEM97 significantly compromised the mitochondria-targeting of Hst1. We further showed the intracellular trafficking and targeting process of F-Hst1, in which early endosome plays an important role. Overall, phagocytosis, CME, GPCR, ERK signaling, and S2R/TMEM97 are involved in the internalization of Hst1, while only CME and S2R/TMEM97 are critical for its subcellular targeting. The inhibition of either internalization or mitochondria-targeting of Hst1 could significantly compromise its mitochondria-activating property.
Endocytosis/physiology* ; Histatins/pharmacology* ; Humans ; Membrane Proteins ; Mitochondria/metabolism* ; RNA, Small Interfering/pharmacology* ; Receptors, G-Protein-Coupled/metabolism* ; Receptors, sigma

Fluvoxamine is a selective serotonin reuptake inhibitor that is approved for psychiatric disorders such as major depressive episodes and obsessive-compulsive disorder. Beside inhibition of serotonin reuptake, fluvoxamine is also a potent agonist of endoplasmic reticulum (ER) protein sigma-1 receptors, which play a role in the pathophysiology of a number of psychiatric and neurodegenerative disorders. This report presents beneficial effects of sigma-1 agonist fluvoxamine on hyperkinetic movement disorders such as tardive dyskinesia and tardive akathisia. Fluvoxamine might be a novel treatmet approach in the treatment of hyperkinetic movement disorders.
Akathisia, Drug-Induced* ; Dyskinesias ; Endoplasmic Reticulum ; Fluvoxamine* ; Humans ; Hyperkinesis ; Movement Disorders* ; Neurodegenerative Diseases ; Obsessive-Compulsive Disorder ; Psychomotor Agitation ; Receptors, sigma ; Schizophrenia* ; Serotonin

Neuropathic pain is a complex chronic pain state caused by the dysfunction of somatosensory nervous system, and it affects the millions of people worldwide. At present, there are very few medical treatments available for neuropathic pain management and the intolerable side effects of medications may further worsen the symptoms. Despite the presence of profound knowledge that delineates the pathophysiology and mechanisms leading to neuropathic pain, the unmet clinical needs demand more research in this field that would ultimately assist to ameliorate the pain conditions. Efforts are being made globally to explore and understand the basic molecular mechanisms responsible for somatosensory dysfunction in preclinical pain models. The present review highlights some of the novel molecular targets like D-amino acid oxidase, endoplasmic reticulum stress receptors, sigma receptors, hyperpolarization-activated cyclic nucleotide-gated cation channels, histone deacetylase, Wnt/β-catenin and Wnt/Ryk, ephrins and Eph receptor tyrosine kinase, Cdh-1 and mitochondrial ATPase that are implicated in the induction of neuropathic pain. Studies conducted on the different animal models and observed results have been summarized with an aim to facilitate the efforts made in the drug discovery. The diligent analysis and exploitation of these targets may help in the identification of some promising therapies that can better manage neuropathic pain and improve the health of patients.
Adenosine Triphosphatases ; Chronic Pain ; Cyclic Nucleotide-Gated Cation Channels ; Drug Discovery ; Endoplasmic Reticulum Stress ; Ephrins ; Histone Deacetylases ; Humans ; Models, Animal ; Nervous System ; Neuralgia* ; Oxidoreductases ; Receptors, Eph Family ; Receptors, sigma

The sigma-1 receptor has recently been implicated in a myriad of cellular functions and biological processes. Previous studies have demonstrated that the spinal sigma-1 receptor plays a pro-nociceptive role in acute pain and that the direct activation of sigma-1 receptor enhances the nociceptive response to peripheral stimuli, which is closely associated with calcium-dependent second messenger cascades including protein kinase C (PKC). In addition, the activation of sigma-1 receptor increases PKC- and protein kinase alpha (PKA)-dependent phosphorylation of the N-Methyl- D-aspartate (NMDA) receptor in the spinal cord, which results in the potentiation of intrathecal NMDA-evoked spontaneous pain behavior. Moreover, the blockade of spinal sigma-1 receptor suppresses the development of neuropathic pain and blocks the increase of phosphorylation of extracellular signal-regulated kinase (ERK) as well as pNR1 in the spinal cord. Recently, it was also reported that spinal neurosteroids such as pregnenolone and dehydroepiandrosterone sulfate, which are recognized as endogenous ligands for sigma-1 receptor, could produce mechanical hypersensitivity via sigma-1 receptor-mediated increase of pNR1. Collectively, these findings demonstrate that the activation of spinal sigma-1 receptor or the increase of neurosteroids is closely associated with the acute pain sensation or the development of chronic pain, and imply that sigma-1 receptor can be a new potential target for the development of analgesics.
Acute Pain ; Analgesics ; Biological Processes ; Central Nervous System Sensitization ; Chronic Pain ; D-Aspartic Acid ; Dehydroepiandrosterone Sulfate ; Hypersensitivity ; Ligands ; Neuralgia ; Neurotransmitter Agents ; Phosphorylation ; Phosphotransferases ; Pregnenolone ; Protein Kinase C ; Protein Kinases ; Receptors, sigma ; Second Messenger Systems ; Sensation ; Spinal Cord

Many therapeutic roles have been proposed for sigma-1 receptor (Sig-1R), but the involvement of Sig-1R in neuropathic pain has currently not been well explored. The present study aimed to evaluate the anti-nociceptive effect of Sig-1R antagonist (BD1047) in a rat model of chronic compression of the dorsal root ganglion (CCD), which is a model of human foraminal stenosis and radicular pain. When stainless steel rods were inserted into the intervertebral foramen of lumbar vertebrae 4 and 5, the CCD developed reliable mechanical (from 3 day) and cold allodynia (from 1 day) as compared with the sham operation group. The spinal expressions of Sig-1R and phosphorylation of extracellular signal-regulated kinase (pERK) were significantly increased from day 3 to day 14 after CCD surgery, as is consistent with the manifestation of allodynia. The BD 1047 (10, 30, 100 mg/kg) administered on postoperative days 0~5 dose-dependently suppressed both the induction of allodynia and the elevation of the spinal pERK expression in a manner comparable with that of gabapentin (100 mg/kg). At 7 days post-CCD surgery, BD1047 (10, 30, 100 mg/kg) administration also produced anti-nociceptive effects on the mechanical and cold allodynia similar with those of gabapentin (100 mg/kg). Therefore, this data suggested that Sig-1R may play an important role in both the development and maintenance of CCD-induced neuropathy.
Amines ; Animals ; Cold Temperature ; Constriction, Pathologic ; Cyclohexanecarboxylic Acids ; Ethylenediamines ; gamma-Aminobutyric Acid ; Ganglia, Spinal ; Humans ; Hyperalgesia ; Lumbar Vertebrae ; Neuralgia ; Phosphorylation ; Phosphotransferases ; Rats ; Receptors, sigma ; Salicylamides ; Spinal Nerve Roots ; Stainless Steel