Paul J. Fletcher

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These studies investigated the effects of antagonists selective for the 5-HT2A, 5-HT2B, or 5-HT2C receptor subtypes on behaviors elicited or maintained by cocaine. The selective 5-HT2A receptor antagonist M100,907 (0.5 mg/kg, SC) attenuated the locomotor activity elicited by 10 mg/kg cocaine, whereas the selective 5-HT2C receptor antagonist SB242,084 (0.5(More)
The present series of studies were designed to investigate the 5-HT(2C) receptor agonist Ro 60-0175 on cocaine- and food-maintained behavior in the rat. Ro 60-0175 (0.1-3 mg/kg, s.c.) reduced cocaine (15 mg/kg, i.p.)-induced hyperactivity. This inhibitory effect of Ro 60-0175 (1 mg/kg, s.c.) was completely blocked by pretreatment with the selective 5-HT(2C)(More)
In the present series of studies, we have investigated the effects of antagonists selective for the 5-HT2A, 5-HT2B and 5-HT2C receptors on motor and 'impulsive'-type behaviours elicited by the non-competitive N-methyl-d-aspartate (NMDA) antagonist dizocilpine. The selective 5-HT2A receptor antagonist M100,907 (0.5 mg/kg) attenuated the hyperlocomotion and(More)
Serotonin (5-HT) has been linked to impulsivity with recent data suggesting that different receptor sub-types exert opposing influences on this behaviour. This work characterised the effects of 5-HT2A (ketanserin, (±)2,3-dimethoxyphenyl-1-[2–4-(piperidine)-methanol] [M100907]), 5-HT2B (6-chloro-5-methyl-1-(5-quinolylcarbamoyl) indoline [SB215505]) and(More)
 Previous studies using a reinstatement procedure have found that acute reexposure to the self-administered drug and exposure to footshock stress reinstate heroin and cocaine seeking after prolonged drug-free periods. Here we tested whether these findings generalize to alcohol-taking behavior. Male rats were initially allowed to consume alcohol in a(More)
Using an animal model of drug relapse, we found that intermittent footshock stress reinstates alcohol seeking, an effect attenuated by the 5-HT reuptake blocker fluoxetine and by corticotropin-releasing factor (CRF) receptor antagonists. Here we studied the role of the 5-HT cell body region of the median raphe nucleus (MRN) and CRF receptors in this site in(More)
The novel antipsychotic aripiprazole requires high (>90%) striatal D2 receptor occupancy (D2RO) to be clinically active, but despite its high D2RO it does not show extrapyramidal symptoms. While most antipsychotics are active at nearly 65% D2RO, they show motor side effects when D2RO exceeds 80%. We investigated this discrepancy between D2RO, 5HT2 receptor(More)
Pharmacological manipulation of the 5-hydroxytryptamine (5-HT; serotonin) system has long been associated with a regulation of feeding behaviour, however, the initial part of this article reviews evidence that central 5-HT systems similarly modulate reward-related behaviours, particularly drug reward. The second part of this article considers what we(More)
BACKGROUND Subcallosal cingulate gyrus (SCG) deep brain stimulation (DBS) is being investigated as a treatment for major depression. We report on the effects of ventromedial prefrontal cortex (vmPFC) DBS in rats, focusing on possible mechanisms involved in an antidepressant-like response in the forced swim test (FST). METHODS The outcome of vmPFC(More)
Previously, we have shown that systemic administration of the 5-HT2C receptor agonist Ro60-0175 reduces cocaine-induced locomotor activity and cocaine self-administration. Ro60-0175 also alters the activity of midbrain dopamine (DA) neurons of the ventral tegmental area (VTA), a region where 5-HT2C receptors are expressed. The present experiments(More)