Male Sprague-Dawley

rats were trained in daily 1 h sessions to intravenously self-administer nicotine (0.03 mg/kg/infusion) on a fixed-ratio 5 schedule. After establishment of stable nicotine self-administration behavior, the effects of the opioid antagonists were tested. Separate groups P005091 of rats were used to test the effects of naloxanazine (selective for mu 1 receptors, 0, 5 and 15 mg/kg), naltrindole (selective for delta receptors, 0, 0.5 and 5 mg/kg), and 5′-guanidinonaltrindole (GNTI, selective for kappa receptors, 0, 0.25 and 1 mg/kg). In each individual drug group, the 3 drug doses were tested by using a within-subject and Latin-Square design. The effects of these antagonists on food self-administering behavior were also examined in the same rats in each respective drug group after retrained for food self-administration. Pretreatment with naloxonazine, but not naltrindole or GNTI, significantly reduced responses on the active lever and correspondingly the number of nicotine

infusions. None of these antagonists changed lever-pressing behavior for food reinforcement. These results indicate that activation of the LY294002 supplier opioid mu 1, but not the delta or the kappa, receptors is required for the reinforcement of nicotine and suggest that opioid neurotransmission via the mu 1 receptors would be a promising target for the development of opioid ligands for smoking cessation. (C) 2010 Elsevier Inc. All rights reserved.”
“Poor cognitive control, including reversal learning deficits, HDAC inhibitor mechanism has been reported in children with attention deficit hyperactivity disorder, in stimulant-dependent humans, and in animal models

of these disorders; these conditions have each been associated with abnormal catecholaminergic function within the prefrontal cortex.\n\nIn the current studies, we sought to explore how elevations in extracellular catecholamine levels, produced by pharmacological inhibition of catecholamine reuptake proteins, affect behavioral flexibility in rats and monkeys.\n\nAdult male Long-Evans rats and vervet monkeys were trained, respectively, on a four-position discrimination task or a three-choice visual discrimination task. Following systemic administration of pharmacological inhibitors of the dopamine and/or norepinephrine membrane transporters, rats and monkeys were exposed to retention or reversal of acquired discriminations.\n\nIn accordance with our a priori hypothesis, we found that drugs that inhibit norepinephrine transporters, such as methylphenidate, atomoxetine, and desipramine, improved reversal performance in rats and monkeys; this was mainly due to a decrease in the number of perseverative errors.