Introduction: The hippocampus (HIP), the primary brain structure related to learning and memory, receives sparse but comprehensive dopamine innervations and contains dopamine D1/D2-like receptors. It is demonstrated that dopamine receptors in dentate gyrus (DG) region of HIP have a remarkable function in spatial reward processing. Much less is known about the involvement of HIP and its D1...

Previous studies have shown that morphine-6-glucuronide (M6G), a metabolite of morphine, induces reward and psychomotor stimulation but the role of the mu opioid receptor in these actions of the drug is not fully characterized. Thus, using mice lacking exon-2 of the mu opioid receptor and their wild-type littermates/controls, we determined the role of this receptor in psychomotor stimulation, s...

Previously, we reported that lateral hypothalamic (LH) orexin neurons are stimulated in proportion to the preference shown for reward-associated cues during conditioned place preference (CPP) testing. Here, we examine for the first time the role of these neurons in the acquisition of morphine CPP. Results show that LH orexin neurons, but not those in the perifornical area (PFA), are stimulated ...

Nicotine is thought to act on brain monoamine systems that normally mediate diverse motivational behaviors. How monoamine-related genes contribute to behavioral traits (e.g. responses to novel stimuli) comorbid with the susceptibility to nicotine addiction is still poorly understood. We examined the impact of constitutive monoamine oxidase A (MAOA) deficiency in mice on nicotine reward and resp...

Introduction: Nitric oxide (NO) is a neuronal messenger molecule in the central nervous system, which is generated from L-arginine by nitric oxide synthase (NOS) and involves in many important opioid-induced effects. Our previous studies revealed that Cuminum cyminum interestingly reduces morphine sensitization, tolerance and dependency in male mice. Therefore, in the present study, the effe...

Introduction: Methamphetamine (METH) is a neurotoxic psychostimulant with highly addictive potential that leads to compulsive drug use and vulnerability to relapse. Environmental cues, such as drug exposure, peer influence, and social stress, are the powerful triggers of drug relapse. In  this  study,  we  tried  to  find  out  the effect of acute and chr...

We investigated the involvement of the hippocampal formation and the amygdala in the acquisition and expression of the amphetamine-produced conditioned place preference (CPP). Animals were conditioned in four sessions that included two pairings of d-amphetamine (2.0 mg/kg, s.c.) with one of two distinct compartments and two pairings of vehicle with the other compartment in a counterbalanced man...

Orexins (also called hypocretins) have been shown to be importantly involved in reward and addiction, but little is known about the circuitry that regulates orexin neuronal activity during drug-seeking behaviors. Here, we examined inputs to the lateral hypothalamus (LH) orexin cell field from the lateral septum (LS) using tract-tracing and Fos immunohistochemistry after cocaine (10 mg/kg) condi...