Perrault G

References (3)

Title : Neurochemical, electrophysiological and pharmacological profiles of the selective inhibitor of the glycine transporter-1 SSR504734, a potential new type of antipsychotic - Depoortere_2005_Neuropsychopharmacology_30_1963
Author(s) : Depoortere R , Dargazanli G , Estenne-Bouhtou G , Coste A , Lanneau C , Desvignes C , Poncelet M , Heaulme M , Santucci V , Decobert M , Cudennec A , Voltz C , Boulay D , Terranova JP , Stemmelin J , Roger P , Marabout B , Sevrin M , Vige X , Biton B , Steinberg R , Francon D , Alonso R , Avenet P , Oury-Donat F , Perrault G , Griebel G , George P , Soubrie P , Scatton B
Ref : Neuropsychopharmacology , 30 :1963 , 2005
Abstract : Noncompetitive N-methyl-D-aspartate (NMDA) blockers induce schizophrenic-like symptoms in humans, presumably by impairing glutamatergic transmission. Therefore, a compound potentiating this neurotransmission, by increasing extracellular levels of glycine (a requisite co-agonist of glutamate), could possess antipsychotic activity. Blocking the glycine transporter-1 (GlyT1) should, by increasing extracellular glycine levels, potentiate glutamatergic neurotransmission. SSR504734, a selective and reversible inhibitor of human, rat, and mouse GlyT1 (IC50=18, 15, and 38 nM, respectively), blocked reversibly the ex vivo uptake of glycine (mouse cortical homogenates: ID50: 5 mg/kg i.p.), rapidly and for a long duration. In vivo, it increased (minimal efficacious dose (MED): 3 mg/kg i.p.) extracellular levels of glycine in the rat prefrontal cortex (PFC). This resulted in an enhanced glutamatergic neurotransmission, as SSR504734 potentiated NMDA-mediated excitatory postsynaptic currents (EPSCs) in rat hippocampal slices (minimal efficacious concentration (MEC): 0.5 microM) and intrastriatal glycine-induced rotations in mice (MED: 1 mg/kg i.p.). It normalized activity in rat models of hippocampal and PFC hypofunctioning (through activation of presynaptic CB1 receptors): it reversed the decrease in electrically evoked [3H]acetylcholine release in hippocampal slices (MEC: 10 nM) and the reduction of PFC neurons firing (MED: 0.3 mg/kg i.v.). SSR504734 prevented ketamine-induced metabolic activation in mice limbic areas and reversed MK-801-induced hyperactivity and increase in EEG spectral energy in mice and rats, respectively (MED: 10-30 mg/kg i.p.). In schizophrenia models, it normalized a spontaneous prepulse inhibition deficit in DBA/2 mice (MED: 15 mg/kg i.p.), and reversed hypersensitivity to locomotor effects of d-amphetamine and selective attention deficits (MED: 1-3 mg/kg i.p.) in adult rats treated neonatally with phencyclidine. Finally, it increased extracellular dopamine in rat PFC (MED: 10 mg/kg i.p.). The compound showed additional activity in depression/anxiety models, such as the chronic mild stress in mice (10 mg/kg i.p.), ultrasonic distress calls in rat pups separated from their mother (MED: 1 mg/kg s.c.), and the increased latency of paradoxical sleep in rats (MED: 30 mg/kg i.p.). In conclusion, SSR504734 is a potent and selective GlyT1 inhibitor, exhibiting activity in schizophrenia, anxiety and depression models. By targeting one of the primary causes of schizophrenia (hypoglutamatergy), it is expected to be efficacious not only against positive but also negative symptoms, cognitive deficits, and comorbid depression/anxiety states.
ESTHER : Depoortere_2005_Neuropsychopharmacology_30_1963
PubMedSearch : Depoortere_2005_Neuropsychopharmacology_30_1963
PubMedID: 15956994

Title : SSR591813, a novel selective and partial alpha4beta2 nicotinic receptor agonist with potential as an aid to smoking cessation - Cohen_2003_J.Pharmacol.Exp.Ther_306_407
Author(s) : Cohen C , Bergis OE , Galli F , Lochead AW , Jegham S , Biton B , Leonardon J , Avenet P , Sgard F , Besnard F , Graham D , Coste A , Oblin A , Curet O , Voltz C , Gardes A , Caille D , Perrault G , George P , Soubrie P , Scatton B
Ref : Journal of Pharmacology & Experimental Therapeutics , 306 :407 , 2003
Abstract : (5aS,8S,10aR)-5a,6,9,10-Tetrahydro,7H,11H-8,10a-methanopyrido[2',3':5,6]pyrano[2, 3-d]azepine (SSR591813) is a novel compound that binds with high affinity to the rat and human alpha4beta2 nicotinic acetylcholine receptor (nAChR) subtypes (Ki = 107 and 36 nM, respectively) and displays selectivity for the alpha4beta2 nAChR (Ki, human alpha3beta4 > 1000, alpha3beta2 = 116; alpha1beta1deltagamma > 6000 nM and rat alpha7 > 6000 nM). Electrophysiological experiments indicate that SSR591813 is a partial agonist at the human alpha4beta2 nAChR subtype (EC50 = 1.3 micro M, IA =19% compared with the full agonist 1,1-dimethyl-4-phenyl-piperazinium). In vivo findings from microdialysis and drug discrimination studies confirm the partial intrinsic activity of SSR591813. The drug increases dopamine release in the nucleus accumbens shell (30 mg/kg i.p.) and generalizes to nicotine or amphetamine (10-20 mg/kg i.p.) in rats, with an efficacy approximately 2-fold lower than that of nicotine. Pretreatment with SSR591813 (10 mg/kg i.p.) reduces the dopamine-releasing and discriminative effects of nicotine. SSR591813 shows activity in animal models of nicotine dependence at doses devoid of unwanted side effects typically observed with nicotine (hypothermia and cardiovascular effects). The compound (10 mg/kg i.p.) also prevents withdrawal signs precipitated by mecamylamine in nicotine-dependent rats and partially blocks the discriminative cue of an acute precipitated withdrawal. SSR591813 (20 mg/kg i.p.) reduces i.v. nicotine self-administration and antagonizes nicotine-induced behavioral sensitization in rats. The present results confirm important role for alpha4beta2 nAChRs in mediating nicotine dependence and suggest that SSR591813, a partial agonist at this particular nAChR subtype, may have therapeutic potential in the clinical management of smoking cessation.
ESTHER : Cohen_2003_J.Pharmacol.Exp.Ther_306_407
PubMedSearch : Cohen_2003_J.Pharmacol.Exp.Ther_306_407
PubMedID: 12682217

Title : Adjustment of permissible exposure values to unusual work schedules - Brodeur_2001_Aihaj_62_584
Author(s) : Brodeur J , Vyskocil A , Tardif R , Perrault G , Drolet D , Truchon G , Lemay F
Ref : Aihaj , 62 :584 , 2001
Abstract : Research activities sought development of a method to adjust exposure limits for 694 substances for unusual work schedules. A consensus was established on the basic toxicological principle for adjustment; criteria for adjustment were selected by a panel of scientists coordinated by a committee of international experts and supported by toxicokinetic modeling; and a group of toxicologists attributed primary health effects and related adjustment category to each substance. A consensus among scientists and employers' and workers' representatives was established on the protocol of the application, in the field, of the adjusted exposure limits. The guiding toxicological principle for adjusting exposure standards to unusual work schedules is to guarantee an equivalent degree of protection for workers with unusual schedules as for workers with a conventional schedule of 8 hours per day, 5 days per week. The process of the adjustment is inspired from the Occupational Safety and Health Administration logic for attribution of primary health effects and adjustment categories ranging from no adjustment to daily or weekly adjustments. The adjusted exposure limits are calculated according to Haber's rule. Decisions on attribution of adjustment categories for the following toxicological effects were reached: respiratory sensitizers (asthma); skin sensitizers; tissue irritants versus tissue toxicants; methemoglobinenia-causing agents; cholinesterase inhibitors; and reproductive system toxicants and teratogens. A simple procedure is presented to facilitate the calculation, application, and interpretation of the adjusted exposure limits.
ESTHER : Brodeur_2001_Aihaj_62_584
PubMedSearch : Brodeur_2001_Aihaj_62_584
PubMedID: 11669384