Dopamine D3 Receptor Modulates Akt/mTOR and ERK Pathways Differently during the Reinstatement of Cocaine-Seeking Behavior Induced by Psychological versus Physiological Stress.

Stress triggers relapses in cocaine use that engage the activity of memory-related nuclei, such as the basolateral amygdala (BLA) and dentate gyrus (DG). Preclinical research suggests that D3 receptor (D3R) antagonists may be a promising means to attenuate cocaine reward and relapse. As D3R regulates the activity of the Akt/mTOR and MEK/ERK pathways, we assessed the effects of SB-277011-A, a D3R antagonist, on the activity of these kinases during the reinstatement of cocaine-induced conditioned place preference (CPP) induced by psychological (restraint) and physiological (tail pinch) stress.

Unraveling the molecular mechanisms involved in alcohol intake and withdrawal in adolescent mice exposed to alcohol during early life stages.

Alcohol interferes with foetal development and prenatal alcohol exposure can lead to adverse effects known as foetal alcohol spectrum disorders. We aimed to assess the underlying neurobiological mechanisms involved in alcohol intake and withdrawal in adolescent mice exposed to alcohol during early life stages, in discrete brain areas. Pregnant C57BL/6 female mice were exposed to binge alcohol drinking from gestation to weaning.

Cardiac Protective Role of Heat Shock Protein 27 in the Stress Induced by Drugs of Abuse.

Heat shock proteins (HSP) are induced after different stress situations. Some of these proteins, particularly HSP-27, function as markers to indicate cellular stress or damage and protect the heart during addictive processes. Morphine withdrawal induces an enhancement of sympathetic activity in parallel with an increased HSP-27 expression and phosphorylation, indicating a severe situation of stress.

Liposome-Encapsulated Morphine Affords a Prolonged Analgesia While Facilitating Extinction of Reward and Aversive Memories.

Morphine is thoroughly used for pain control; however, it has a high addictive potential. Opioid liposome formulations produce controlled drug release and have been thoroughly tested for pain treatment although their role in addiction is still unknown. This study investigated the effects of free morphine and morphine encapsulated in unilamellar and multilamellar liposomes on antinociception and on the expression and extinction of the positive and negative memories associated with environmental cues.

Role of glucocorticoids on noradrenergic and dopaminergic neurotransmission within the basolateral amygdala and dentate gyrus during morphine withdrawal place aversion.

Aversive memories related to drug withdrawal can generate a motivational state leading to compulsive drug taking. However, the mechanisms underlying the generation of these withdrawal memories remain unclear. Limbic structures, such as the basolateral amygdala (BLA) and the dentate gyrus (DG) of the hippocampus, play a crucial role in the negative affective component of morphine withdrawal.

Regulation of Pleiotrophin, Midkine, Receptor Protein Tyrosine Phosphatase β/ζ, and Their Intracellular Signaling Cascades in the Nucleus Accumbens During Opiate Administration.

Background: Most classes of addictive substances alter the function and structural plasticity of the brain reward circuitry. Midkine (MK) and pleiotrophin (PTN) are growth/differentiation cytokines which, similarly to neurotrophins, play an important role in repair, neurite outgrowth, and cell differentiation. PTN or MK signaling through receptor protein tyrosine phosphatase β/ζ (RPTPβ/ζ), leads to the activation of extracellular signal-regulated kinases and thymoma viral proto-oncogene.

Morphine regulates Argonaute 2 and TH expression and activity but not miR-133b in midbrain dopaminergic neurons.

Epigenetic changes such as microRNAs (miRs)/Ago2-induced gene silencing represent complex molecular signature that regulate cellular plasticity. Recent studies showed involvement of miRs and Ago2 in drug addiction. In this study, we show that changes in gene expression induced by morphine and morphine withdrawal occur with concomitant epigenetic modifications in the mesolimbic dopaminergic (DA) pathway [ventral tegmental area (VTA)/nucleus accumbens (NAc) shell], which is critically involved in drug-induced dependence.

Effects of U-50488H and U-50488H withdrawal on c-fos expression in the rat paraventricular nucleus. Correlation with c-fos in brainstem catecholaminergic neurons.

1. In the present work, we have studied the expression of Fos during acute and chronic administration of the kappa-opioid receptor agonist U-50488H and after U-5088H withdrawal in the rat hypothalamic paraventricular nucleus (PVN). Fos production was also studied in brainstem regions that innervate the PVN: the A(2) cell group of the nucleus of solitary tract (NTS-A(2)) and the A(1) cell group of the ventrolateral medulla (VLM-A(1)), combined with immunostaining for tyrosine hydroxylase (TH) for immunohistochemical identification of active neurons after acute U-50488H administration.

Effects of morphine and morphine withdrawal on brainstem neurons innervating hypothalamic nuclei that control the pituitary-adrenocortical axis in rats.

Different data support a role for brainstem noradrenergic inputs to the hypothalamic paraventricular nucleus (PVN) in the control of hypothalamus - pituitary - adrenocortical (HPA) axis. However, little is known regarding the functional adaptive changes of noradrenergic afferent innervating the PVN and supraoptic nucleus (SON) during chronic opioid exposure and upon morphine withdrawal. Here we have studied the expression of Fos after administration of morphine and during morphine withdrawal in the rat hypothalamic PVN and SON.