Immediate early and constitutively expressed products of the Homer1 gene regulate the functional assembly of post-synaptic density proteins at glutamatergic synapses to influence excitatory neurotransmission and synaptic plasticity. Earlier studies of Homer1 gene knock-out (KO) mice indicated active, but distinct, roles for IEG and constitutively expressed Homer1 gene products in regulating cog...

The purpose of this study was to compare the effects of amphetamine exposure on subsequent amphetamine-induced changes in behavior and dopamine (DA) release in the dorsal and ventral striatum, as a function of time following the discontinuation of repeated amphetamine treatment. Rats were pretreated with either saline or an escalating-dose amphetamine regimen, and then received a 0.5 mg/kg amph...

Methylphenidate (MPD) is a psychostimulant used in the treat treatment of attention deficit hyperactivity disorder and more recently is being used as a cognitive enhancement and recreational drug. Its therapeutic effects are not fully understood, nor are the long term effects of the drug on brain development. The ventral tegmental area (VTA) is a site of psychostimulant action thought to be inv...

In rodents, drugs of abuse induce locomotor hyperactivity, and repeating injections enhances this response. This effect, called behavioral sensitization, persists many months after the last administration, thus mimicking long-term sensitivity to drugs observed in human addicts. We show here that, in naïve animals, noradrenergic and serotonergic systems, besides their behavioral activating effec...

The relationship between the effects of the N-methyl-D-aspartate (NMDA) antagonist MK-801 on acute responses to ethanol and its ability to block ethanol sensitization and tolerance was examined in DBA/2J mice. Cross-sensitization between these drugs was also studied. Repeated administration of 0.1 mg/kg MK-801 with ethanol potentiated, whereas 0.25 mg/kg attenuated, sensitization to ethanol's l...

In previous study, we demonstrated that ethanol preexposure may increase ethanol consumption in both adolescent and adult mice, in a two-bottle choice model. We now questioned if ethanol exposure during adolescence results in changes of consumption pattern using a three-bottle choice procedure, considering drinking-in-the-dark and alcohol deprivation effect as strategies for ethanol consumption...

Methylphenidate (MPD) is a readily prescribed drug for the treatment of attention deficit hyperactivity disorder (ADHD) and moreover is used illicitly by youths for its cognitive-enhancing effects and recreation. MPD exposure in rodents elicits increased locomotor activity. Repetitive MPD exposure leads to further augmentation of their locomotor activity. This behavioral response is referred to...

Investigations using the fruit fly Drosophila melanogaster have shown that the circadian clock gene period (Per) can influence behavioral responses to cocaine. Here we show that the mouse homologues of the Drosophila Per gene, mPer1 and mPer2, modulate cocaine sensitization and reward, two phenomena extensively studied in humans and animals because of their importance for drug abuse. In respons...

The effects of the competitive NMDA receptor antagonist CPP on the initiation of behavioral sensitization to acute cocaine and basal and acute cocaine-induced dopamine (DA) release in the nucleus accumbens (NAC) were assessed in female Sprague-Dawley rats. Cocaine pretreated rats (30 mg/kg IP, once daily for 7 days) challenged with cocaine (10 mg/kg) on day 8 displayed increased motor activity ...