ro-60-0175 and lorcaserin

Topics: Animals; Benzazepines; Disease Models, Animal; Ethylamines; Fenfluramine; Indoles; Mice; Piperazines; Pyrazines; Rats; Receptor, Serotonin, 5-HT2C; Seizures; Serotonin 5-HT2 Receptor Agonists; Treatment Outcome

Selective 5-HT2C receptor agonists, such as lorcaserin, are being developed for the treatment of obesity. Studies suggest that they may also have therapeutic potential for addictive behaviours including nicotine dependence, although few drugs of this class have been evaluated.. The primary aim was to evaluate the highly selective 5-HT2C agonist, CP-809101, against food-motivated (operant FR5 and progressive ratio schedules, palatability-induced feeding) and nicotine-motivated (intravenous self-administration, drug discrimination) behaviours in rats and to compare with equivalent findings for the structurally distinct 5-HT2C receptor agonists lorcaserin and Ro 60-0175. The secondary aims were to evaluate the side effect profiles of lorcaserin and CP-809101 and to determine the plasma levels of lorcaserin at a dose (1 mg/kg) that reduces both food and nicotine reinforcement for comparison to plasma concentrations reported in human trials.. CP-809101 (0.3-3 mg/kg SC) reduced responding for both nicotine and food and blocked the discriminative stimulus properties of nicotine in a similar manner to lorcaserin and Ro 60-0175. Behaviours such as hypolocomotion, chewing and ptosis became evident following both CP-809101 and lorcaserin administration at higher doses. Plasma levels of lorcaserin were of similar range to those reported in obesity trials.. These studies support the utility of 5-HT2C agonists as a therapeutic approach to treat nicotine dependence. Plasma exposure levels after acute lorcaserin treatment suggest that equivalent dosages could be used to evaluate these drugs in obesity and smoking cessation trials. Finally, there may be differences in the side effect profiles between lorcaserin and CP-809101, raising the possibility for tolerability differences amongst 5-HT2C agonists.

Topics: Animals; Behavior, Animal; Benzazepines; Dose-Response Relationship, Drug; Ethylamines; Feeding Behavior; Indoles; Male; Motivation; Nicotine; Piperazines; Pyrazines; Rats; Rats, Sprague-Dawley; Receptor, Serotonin, 5-HT2C; Reinforcement Schedule; Self Administration; Serotonin 5-HT2 Receptor Agonists

5-HT(2C) receptor agonists have considerable therapeutic potential, however there is little in vivo data to compare the potency and selectivity of 5-HT(2C) receptor agonists. Since 5-HT(2C) receptor agonists reduce locomotor activity and food intake, changes in these drug-induced behaviours in 5-HT(2C) receptor knockout mice could provide a means to examine receptor selectivity in-vivo. Initially this study compared older 5-HT(2C) agonists mCPP and MK212, to newer, apparently more selective compounds: Ro 60-0175, WAY161503, CP809,101 and lorcaserin (APD356) on motor activity in wild-type, and 5-HT(2C) receptor knockout mice. Two 5-HT(2C) receptor antagonists SB242084 and SDZ SER 082 were also examined. mCPP did not significantly alter activity in wild-type mice, but enhanced activity in knockout animals. MK212 (3 and 10 mg/kg) and Ro 60-0175 (1 and 3 mg/kg) reduced activity in wild-type but not knockout animals. At 10 mg/kg, Ro 60-0175 reduced activity in knockout animals, suggesting loss of 5-HT(2C) receptor selectivity. CP809,101 and lorcaserin reduced activity in wild-type but not knockout mice. In subsequent feeding studies, Ro 60-0175 and lorcaserin reduced food intake in wild-type animals only. Selectivity of effect for mCPP was marginal. The antagonist SB242084 increased activity in wild-type animals but not in knockout mice; SB242084 did not alter feeding in either genotype. SDZ SER 082 reduced activity in both genotypes implying poor selectivity for 5-HT(2C) receptors. The data demonstrate that studying food intake, and particularly motor behaviour, in the 5-HT(2C) receptor knockout mouse is a useful and relatively simple approach for screening 5-HT(2C) receptor ligands in vivo.

Topics: Aminopyridines; Animals; Benzazepines; Dexfenfluramine; Eating; Ethylamines; Feeding Behavior; Indoles; Ligands; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Motor Activity; Naphthyridines; Piperazines; Pyrazines; Quinoxalines; Receptor, Serotonin, 5-HT2C; Serotonin Antagonists; Serotonin Receptor Agonists

The synthesis and SAR of a novel 3-benzazepine series of 5-HT2C agonists is described. Compound 7d (lorcaserin, APD356) was identified as one of the more potent and selective compounds in vitro (pEC50 values in functional assays measuring [(3)H]phosphoinositol turnover: 5-HT2C = 8.1; 5-HT2A = 6.8; 5-HT2B = 6.1) and was potent in an acute in vivo rat food intake model upon oral administration (ED50 at 6 h = 18 mg/kg). Lorcaserin was further characterized in a single-dose pharmacokinetic study in rat (t1/2 = 3.7 h; F = 86%) and a 28-day model of weight gain in growing Sprague-Dawley rat (8.5% decrease in weight gain observed at 36 mg/kg b.i.d.). Lorcaserin was selected for further evaluation in clinical trials for the treatment of obesity.

Topics: Animals; Anti-Obesity Agents; Benzazepines; Cell Line; Eating; Humans; Inositol 1,4,5-Trisphosphate; Male; Obesity; Rats; Rats, Sprague-Dawley; Serotonin 5-HT2 Receptor Agonists; Stereoisomerism; Structure-Activity Relationship; Weight Gain