The memory reconsolidation hypothesis suggests that a memory trace becomes labile after retrieval and needs to be reconsolidated before it can be stabilized. However, it is unclear from earlier studies whether the same synapses involved in encoding the memory trace are those that are destabilized and restabilized after the synaptic reactivation that accompanies memory retrieval, or whether new ...

It has been proposed that some neuroadaptations that underlie behavioral sensitization may play a role in the development and persistence of addiction. However, whether or not sensitization facilitates the development of symptoms specific to addiction, such as the escalation of drug intake, is not known. We examined, therefore, the effect of pretreatment with a sensitizing regimen of amphetamin...

The alpha-subunits of the trimeric Go class of GTPases, comprising the splice variants Go1alpha and Go2alpha, are abundantly expressed in brain and reside on both plasma membrane and synaptic vesicles. Go2alpha is involved in the vesicular storage of monoamines but its physiological relevance is still obscure. We now show that genetic depletion of Go2alpha reduces motor activity induced by dopa...

The gold standard therapy for Parkinson's disease (PD) consists in chronic administration of pulses of the dopamine (DA) precursor l-dihydroxyphenylalanine (l-DOPA). Although the main brain area which is DA-deficient is the dorsal striatum (more the putamen than the caudate nucleus), other DA-innervated brain regions (i.e., the ventral striatum and other limbic areas) are affected by systemic a...

Repeated administration of cocaine progressively increases drug-induced locomotor activity. This study examined the role of dopamine D(1)- and D(2)-like receptors in the medial prefrontal cortex (mPFC) in mediating these sensitized behaviors. For initiation experiments, animals received bilateral intra-mPFC injections of either saline, the D(1)-like agonist SKF 81297 (3 nmol/side) or the D(2)-l...

Calcineurin is a serine/threonine phosphatase that contributes to the effects of nicotine on calcium signaling in cultured cortical neurons; however, the role of calcineurin in behavioral responses to nicotine in vivo has not been examined. We therefore determined whether calcineurin blockade could alter nicotine-mediated locomotor sensitization in Sprague Dawley rats using systemic or brain re...

Synaptic plasticity at excitatory synapses has been proposed as the cellular substrate of information processing and memory formation in the brain under both physiological and pathological conditions, including addiction. There is a growing body of evidence that implicates long-term depression (LTD), particularly in the nucleus accumbens (NAc), as a potential mediator of drug-induced neural pla...

Behavioral sensitization of psychostimulant-induced locomotor activity in rats has been proposed as a model of addiction and is accompanied by neuroadaptations in the nucleus accumbens and related circuits. Here, we used in vivo intracellular recordings to examine electrophysiological properties of accumbens neurons from animals that did or did not exhibit behavioral sensitization after repeate...

introduction: topiramate is a newly anti-convulsant drug, which acts as nmda glutamate receptor antagonist as well as the gabab receptor agonist. it is used for physical dependence to opioids as well as cocaine, nicotine, alcohol and ecstasy dependence. in the present study attempts were made to further identification of the effects of topiramate on the acquisition and expression of morphine-in...