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opioid system, seizure

Mehdi Sheikhi, Armin Shirzadian, Amir Dehdashtian, Shayan Amiri, Sattar Ostadhadi, Mehdi Ghasemi, Ahmad Reza Dehpour
Zolpidem is a hypnotic medication that mainly exerts its function through activating γ-aminobutyric acid (GABA)A receptors. There is some evidence that zolpidem may have anticonvulsive effects. However, the mechanisms underlying this effect have not been elucidated yet. In the present study, we used the pentylentetrazole (PTZ)-induced generalized seizure model in mice to investigate whether zolpidem can affect seizure threshold. We also further evaluated the roles of ATP-sensitive potassium (KATP) channels as well as μ-opioid receptors in the effects of zolpidem on seizure threshold...
September 2016: Epilepsy & Behavior: E&B
Mehruba Anwar, Royal Law, Josh Schier
Kratom (Mitragyna speciosa) is a plant consumed throughout the world for its stimulant effects and as an opioid substitute (1). It is typically brewed into a tea, chewed, smoked, or ingested in capsules (2). It is also known as Thang, Kakuam, Thom, Ketum, and Biak (3). The Drug Enforcement Administration includes kratom on its Drugs of Concern list (substances that are not currently regulated by the Controlled Substances Act, but that pose risks to persons who abuse them), and the National Institute of Drug Abuse has identified kratom as an emerging drug of abuse (3,4)...
2016: MMWR. Morbidity and Mortality Weekly Report
Xiu Wang, Yao Wang, Chao Zhang, Chang Liu, Baotian Zhao, Naili Wei, Jian-Guo Zhang, Kai Zhang
Both endocannabinoids and dynorphin are feedback messengers in nervous system that act at the presynaptic nerve terminal to inhibit transmitter release. Many studies showed the cannabinoid-opioid cross-modulation in antinociception, hypothermia, sedation and reward. The aim of this study was to assess the influence of early application of cannabinoid type 1 (CB1) receptor antagonism SR141716A after brain injury on dynorphin-κ opioid receptor (KOR) system and the expression of metabotropic glutamate receptors (mGluRs) in a rat model of fluid percussion injury (FPI)...
September 1, 2016: Brain Research
Gina F Marrone, Steven G Grinnell, Zhigang Lu, Grace C Rossi, Valerie Le Rouzic, Jin Xu, Susruta Majumdar, Ying-Xian Pan, Gavril W Pasternak
The clinical management of severe pain depends heavily on opioids acting through mu opioid receptors encoded by the Oprm1 gene, which undergoes extensive alternative splicing. In addition to generating a series of prototypic seven transmembrane domain (7TM) G protein-coupled receptors (GPCRs), Oprm1 also produces a set of truncated splice variants containing only six transmembrane domains (6TM) through which selected opioids such as IBNtxA (3'-iodobenzoyl-6β-naltrexamide) mediate a potent analgesia without many undesirable effects...
March 29, 2016: Proceedings of the National Academy of Sciences of the United States of America
Hamed Shafaroodi, Elnaz Khosravani, Ali Fakhrzad, Leila Moezi
OBJECTIVES: Morphine and propranolol have different effects on seizure. Several studies have shown interaction between adrenergic and opioid systems in different models. In this study, interaction between morphine and propranolol in different seizure models was examined in mice. METHODS: In this study, three seizure models, including intravenous pentylenetetrazole (PTZ), intraperitoneal PTZ and electroshock, were examined in mice. Animals were injected with different doses of morphine or propranolol in the 60th and 45th min, before seizure induction, respectively...
February 2016: Neurological Research
Mahsa Hassanipour, Armin Shirzadian, Mahdi Mashhadi-Akbar Boojar, Aminreza Abkhoo, Alireza Abkhoo, Sina Delazar, Shayan Amiri, Nastaran Rahimi, Sattar Ostadhadi, Ahmad-Reza Dehpour
Chloroquine has long been used for the treatment of malaria and rheumatological disorders. Accumulating evidence suggests potential use of chloroquine as a neuroprotective agent. Several studies have reported that endogenous opioids and nitric oxide (NO) system mediate the chloroquine effects. In the present study, the involvements of endogenous opioids and NO in the modulatory effects of chloroquine on pentylenetetrazol-induced seizures were assessed in mice. Chloroquine 5mg/kg significantly increased the seizure threshold, but this effect was reversed with naltrexone 1mg/kg...
March 2016: Brain Research Bulletin
Saeed Mehrzadi, Asie Shojaii, Sogol Attari Pur, Manijeh Motevalian
This study investigated the anticonvulsant activity of Citrullus colocynthis fruit extract used traditionally in the treatment of convulsion. Albino mice were pretreated with extract in different doses (10, 25, 50, and 100 mg/kg), prior to injection of pentylenetetrazole. Animals received pretreatments with naloxone and flumazenil to further clarify the mechanisms of anticonvulsant action. The total flavonoid content of Citrullus colocynthis extract was also determined. Citrullus colocynthis hydroalcoholic extract with doses 25 and 50 mg/kg prolonged the onset of seizures and decreased the duration compared with control group...
October 2016: Journal of Evidence-based Complementary & Alternative Medicine
Richard J Bodnar
This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants)...
January 2016: Peptides
Deniz Yilmazer-Hanke, Elaine O'Loughlin, Kieran McDermott
The amygdala contributes to the generation and propagation of epileptiform activity in temporal lobe epilepsy (TLE). Ictal symptoms such as fear, dreamy states (déjà vu, memory flashbacks, experiential hallucinations), epigastric auras, or sympathetic outflow with cardiovascular changes are often linked to a seizure focus in the amygdala. However, the amygdala may also play a role in comorbid anxiety, depression, and other psychiatric symptoms experienced in the interictal phase, especially in pharmacoresistant TLE...
June 2016: Journal of Neuroscience Research
Hossein Amini-Khoei, Maryam Rahimi-Balaei, Shayan Amiri, Arya Haj-Mirzaian, Mahsa Hassanipour, Armin Shirzadian, Maziar Gooshe, Sakineh Alijanpour, Shahram Ejtemaie Mehr, Ahmad Reza Dehpour
Histamine regulates release of neurotransmitters such as dopamine, serotonin, gamma-aminobutyric acid (GABA), glutamate and also is involved in several functions in central nervous system (CNS). It has been shown that histamine participates in disorders like seizure. It has been well documented that morphine dose-dependently induces anti or proconvulsant effects. In the current study, we firstly showed that morphine (1mg/kg) exerts anticonvulsant effects which significantly reversed by naltrexone administration...
December 15, 2015: European Journal of Pharmacology
Hossein Amini-Khoei, Shayan Amiri, Armin Shirzadian, Arya Haj-Mirzaian, Sakineh Alijanpour, Maryam Rahimi-Balaei, Ali Mohammadi-Asl, Mahsa Hassanipour, Shahram Ejtemaie Mehr, Ahmad Reza Dehpour
Experiencing early-life stress has been considered as a potent risk factor for the development of many of brain disorders, including seizures. Intervening mechanisms through which neonatal maternal separation (MS) alters the seizure susceptibility in adulthood have not been well studied. In the current study, by applying 180 min of MS stress (PND 2-14), we determined the seizure susceptibility and considered the role of the opioid system. Maternal separation increased the seizure threshold, and administration of anticonvulsant/proconvulsant doses of morphine (1 and 30 mg/kg, respectively) reversed the impact of MS...
November 2015: Epilepsy & Behavior: E&B
Ben T Tsutaoka, Raymond Y Ho, Stacey M Fung, Thomas E Kearney
BACKGROUND: Tapentadol (TAP) and tramadol (TRA) provide pain relief through similar monoaminergic and opioid agonist properties. OBJECTIVE: To compare clinical effects and medical outcomes between TAP and TRA exposures reported to the National Poison Data System of the American Association of Poison Control Centers. METHODS: A retrospective cohort study was conducted analyzing national data for single medication TAP or TRA cases reported from June 2009 through December 2011...
December 2015: Annals of Pharmacotherapy
Richard R Neubig
Guanine nucleotide-binding proteins of the inhibitory (Gi/o) class play critical physiological roles and the receptors that activate them are important therapeutic targets (e.g., mu opioid, serotonin 5HT1a, etc.). Gi/o proteins are negatively regulated by regulator of G protein signaling (RGS) proteins. The redundant actions of the 20 different RGS family members have made it difficult to establish their overall physiological role. A unique G protein mutation (G184S in Gαi/o) prevents RGS binding to the Gα subunit and blocks all RGS action at that particular Gα subunit...
2015: Progress in Molecular Biology and Translational Science
Nicole M Ryan, Geoffrey K Isbister
CONTEXT: Tramadol is a commonly used centrally acting analgesic associated with seizures and suspected to cause serotonin toxicity in overdose. OBJECTIVE: This study sought to investigate the effects of tramadol overdose, and included evaluation for serotonin toxicity based on the Hunter Serotonin Toxicity Criteria where the seven clinical features of spontaneous clonus, inducible clonus, ocular clonus, agitation, diaphoresis, tremor and hyperreflexia are examined for in all patients taking serotonergic medications; seizures and central nervous system depression...
July 2015: Clinical Toxicology
Leila Moezi, Fatema Pirsalami, Soroor Inaloo
Epilepsy is characterized by spontaneous recurrent seizures and represents one of the most frequent neurological diseases, affecting about 60 million people worldwide. The cellular and neurocircuit bases of epilepsy are poorly understood. Constipation is a common gastrointestinal disorder characterized by symptoms such as straining, hard stool, and infrequent defecation. Population-based studies have shown that the prevalence of constipation is up to 30% of the population in developed countries. The causal link between seizure and constipation is a common belief among patients and physicians, but there are no scientific data to support this association...
March 2015: Epilepsy & Behavior: E&B
Muhammad Imran Khan, Armin Shirzadian, Arya Haj-Mirzaian, Shahram Ejtemaei Mehr, Ahmad Reza Dehpour, Maryam Rahimi-Balaei, Shayan Amiri
Opioid system has been reported to be involved in the consequences of post-weaning social isolation stress (SIS) such as hypoalgesia and social behaviors. Also, previous studies have shown that SIS increases mu opioid receptor expression in the regions of the brain associated with epileptogenesis such as basolateral amygdala and cortex. Interestingly, experiencing SIS increases seizure risk in the adulthood. Regarding the SIS-induced alterations in the opioid system, we hypothesize that increase in opioidergic system activity (mostly by mu receptor) may be associated with increase in vulnerability to seizures...
May 2015: Medical Hypotheses
M R Palizvan, E Ghaznavi-Rad
The role of opioid receptor and voltage dependent calcium channels on the kindling induced by the convulsant pentylenetetrazole (PTZ) were investigated in the rats. Experiment involved 24 rats which were divided into four groups. Kindling was established with PTZ in subconvulsive dose (37.5 mg/kg i.p.) every 48 h and effects were observed within 20 min using five-point scoring system. All animals were kindled to three consecutive-stage five seizures and their stability was tested. Saline, verapamil (calcium channel blocker), naloxone (opioid antagonist) or both of them were then administrated 20 min before PTZ application...
July 2014: Research in Pharmaceutical Sciences
Maziar Gooshe, Amir Hossein Abdolghaffari, Ali Reza Aleyasin, Leila Chabouk, Sina Tofigh, Gholam Reza Hassanzadeh, Borna Payandemehr, Alireza Partoazar, Yaser Azizi, Ahmad Reza Dehpour
Stroke is a leading cause of death, disability, and socioeconomic loss worldwide. All attempts at pharmacological reduction of the complications of stroke (e.g. post-stroke seizure, and brain׳s vulnerability to hypoxic/ischemic injury) have failed. Endogenous opioids and nitric oxide (NO) overproduction has been documented in brain hypoxia/ischemia (H/I), which can exert pro-convulsive effects. In this study, we aimed to examine the possible involvement of opioidergic and nitrergic pathways in the pathogenesis of post-stroke seizure...
January 5, 2015: European Journal of Pharmacology
Paul Chu Sin Chung, Annie Boehrer, Aline Stephan, Audrey Matifas, Grégory Scherrer, Emmanuel Darcq, Katia Befort, Brigitte L Kieffer
The delta opioid receptor (DOR) has raised much interest for the development of new therapeutic drugs, particularly to treat patients suffering from mood disorders and chronic pain. Unfortunately, the prototypal DOR agonist SNC80 induces mild epileptic seizures in rodents. Although recently developed agonists do not seem to show convulsant properties, mechanisms and neuronal circuits that support DOR-mediated epileptic seizures remain to be clarified. DORs are expressed throughout the nervous system. In this study we tested the hypothesis that SNC80-evoked seizures stem from DOR activity at the level of forebrain GABAergic transmission, whose inhibition is known to facilitate the development of epileptic seizures...
February 1, 2015: Behavioural Brain Research
Kelly J Buerger, Richard Salazar
A 20-year-old man presented to the neurotrauma intensive care unit following blunt head injury. MRI revealed subarachnoid haemorrhage and multiple intraparenchymal haemorrhages suggesting severe brain injury. During recovery, the patient displayed intermittent episodes of alternating hemibody spasms with decerebrate/decorticate dystonic posturing. Episodes presented with autonomic dysregulation including hyperthermia, diaphoresis, tachypnoea, tachycardia and hypertension. Concern for seizure activity prompted simultaneous video monitoring and EEG testing...
2014: BMJ Case Reports
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