levorphanol and Disease-Models--Animal

The selective serotonin (5-HT) reuptake inhibitors (SSRIs) represent the first-line pharmacotherapy for obsessive-compulsive disorder (OCD), and atypical antipsychotic drugs, which block 5-HT2A receptors, are used in augmentation strategies. Opiate drugs are also effective in treatment-refractory OCD and Tourette syndrome. The 5-HT2A-related behavior (i.e., head twitch) has been related with tics, stereotypes, and compulsive symptoms observed in Tourette syndrome and OCD.. The aim of this study was to explore whether 5-HT2A-related behavior is affected by atypical opiate drugs.. Head-twitch response was induced in mice by administration of either 5-hydroxytryptophan (5-HTP) or the 5-HT2A/C agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). Dose-effect curves of atypical opiate drugs [(+/-)-tramadol, (-)-methadone and levorphanol], morphine, and other psychoactive drugs (fluvoxamine, desipramine, nefazodone, and clozapine) were performed. Opioid mechanisms were investigated by administration of naloxone.. All the opiates tested reduced both 5-HTP and DOI-induced behavior in a naloxone-reversible fashion, atypical opiates being more effective. The effects of the other drugs depended on the protocol, clozapine being the most effective.. Combined 5-HT and opioid properties result in a greater efficacy in antagonizing 5-HT2A-related behavior. These results provide behavioral evidence to support convergent effects of the 5-HT and opioid systems in discrete brain areas, offering the potential for therapeutic advances in the management of refractory stereotypes and compulsive behaviors.

Topics: 5-Hydroxytryptophan; Analgesics, Opioid; Animals; Clozapine; Desipramine; Disease Models, Animal; Dose-Response Relationship, Drug; Fluvoxamine; Indophenol; Levorphanol; Male; Methadone; Mice; Morphine; Naloxone; Narcotic Antagonists; Obsessive-Compulsive Disorder; Piperazines; Receptor, Serotonin, 5-HT2A; Receptor, Serotonin, 5-HT2C; Stereotyped Behavior; Tics; Tourette Syndrome; Tramadol; Triazoles

Acute morphine dependence was compared in mice selectively-bred for high (HA) and low (LA) swim stress-induced analgesia and high (HAR) and low (LAR) levorphanol analgesia by counting the number of naloxone-precipitated jumps. Whereas LAR mice displayed greater acute morphine dependence than HAR mice, HA and LA mice did not differ. No genotypic differences were observed in non-dependent mice, discounting possible differences in basal naloxone sensitivity and/or opioid peptide levels. Thus, the two selection projects, while both producing lines exhibiting highly divergent sensitivity to morphine analgesia, have not had analogous effects on all opioid measures, supporting the notion of independent genetic mediation of opioid analgesia and dependence. Further, these data suggest that analgesic sensitivity may not predict sensitivity to morphine dependence.

Topics: Analgesia; Animals; Behavior, Animal; Disease Models, Animal; Exercise Test; Levorphanol; Male; Mice; Mice, Inbred Strains; Morphine; Morphine Dependence; Naloxone; Selection, Genetic

The dextrorotatory morphinan dextromethorphan (DM), a clinically tested antagonist of the N-methyl-D-aspartate (NMDA) receptor-channel complex, was tested in an in vivo model of acute transient focal cerebral ischemia. Rabbits were randomly assigned to pretreatment with a 20 mg/kg i.v. bolus followed by 10 mg/kg/h of 0.4% DM in normal saline (NS), or with an equivalent volume of NS alone. They then underwent 1 h occlusion of the left internal carotid artery an anterior cerebral artery followed by 4 h of reperfusion. DM-treated animals showed a significant decrease in the percentage of severe neocortical ischemic neuronal damage (10.5%), as compared to NS-treated animals (49.6%).

Topics: Animals; Cerebral Cortex; Dextromethorphan; Disease Models, Animal; In Vitro Techniques; Ischemic Attack, Transient; Levorphanol; Male; Rabbits

Topics: Animals; Choice Behavior; Disease Models, Animal; Dopamine; Drinking Behavior; Female; Fenclonine; Humans; Hydroxydopamines; Levorphanol; Morphine Dependence; Norepinephrine; Rats; Rats, Inbred Strains; Self Administration; Serotonin; Substance-Related Disorders; Sucrose; Sweetening Agents