Learned associations between environmental cues and morphine use play an important role in the maintenance and/or relapse of opioid addiction. Although previous studies suggest that context-dependent morphine treatment alters glutamatergic transmission and synaptic plasticity in the hippocampus, their role in morphine conditioned place preference (CPP) and reinstatement remains unknown. We inve...

Nicotine is classified as a dependence-producing drug. This study investigated the rewarding property of nicotine employing the conditioned place preference (CPP) paradigm in a three-compartment box, and compared it with that of methamphetamine (MAP). In place conditioning using a biased method, rats were placed in one (white or black) compartment under the drug treatment and placed in the othe...

The acute effects of marijuana consumption on brain physiology and behaviour are well documented, but the long-term effects of its chronic use are less well known. Chronic marijuana use during adolescence is of increased interest, given that the majority of individuals first use marijuana during this developmental stage , and adolescent marijuana use is thought to increase the susceptibility t...

Adviser: Shirzad Jenab, Ph.D. The development and maintenance of cocaine addiction and relapse after abstinence depend heavily on learned associations between environmental stimuli and the rewarding properties of the drug. Cocaine and other abused drugs activate intracellular signaling cascades throughout the mesocorticolimbic reward circuitry, leading to functional changes in brain structure. ...

Rodent studies have proposed that adolescent susceptibility to substance use is at least partly due adolescents experiencing reduced aversive effects of drugs compared adults. We thus investigated methamphetamine (meth) conditioned place preference/aversion (CPP/CPA) in and adult mice both sexes using a high dose meth (3 mg/kg) or saline as controls. Mice tagged with green-fluorescent protein (...

The interaction of amphetamine (AMPH) with the dopamine (DA) transporter (DAT) is thought to be critically important for the DA-elevating actions of this drug. It is commonly believed that DA elevations are involved in the rewarding/reinforcing properties of AMPH and other drugs of abuse. Here, we found that DAT deletion did not eliminate the rewarding effects of AMPH as measured by conditioned...

Diet-induced obesity (DIO) causes ghrelin resistance in hypothalamic Agouti-related peptide (AgRP) neurons. However, ghrelin promotes feeding through actions at both the hypothalamus and mesolimbic dopamine reward pathways. Therefore, we hypothesized that DIO would also establish ghrelin resistance in the ventral tegmental area (VTA), a major site of dopaminergic cell bodies important in reward...

In golden hamsters, the expression of a conditioned place preference (CPP) or avoidance (CPA) is regulated in a circadian pattern such that the preference and avoidance are exhibited strongly at the circadian time of prior training, but not at other circadian times. In the rat, reports are conflicting regarding whether time of day learning is evident. We investigated whether this conflict arise...