Neuroscience
-
Although opioid addiction has risen dramatically, the role of gender in addiction has been difficult to elucidate. We previously found sex-dependent differences in the hippocampal opioid system of Sprague-Dawley rats that may promote associative learning relevant to drug abuse. The present studies show that although female and male rats acquired conditioned place preference (CPP) to the mu-opioid receptor (MOR) agonist oxycodone (3 mg/kg, I. ⋯ In dentate hilar GABAergic dendrites that contain neuropeptide Y, Sal-females compared to Sal-males had higher plasmalemmal DORs, and near-plasmalemmal DORs increased in Oxy-females. This redistribution of MORs and DORs within hilar interneurons in Oxy-females would potentially enhance disinhibition of granule cells via two different circuits. Together, these results indicate that oxycodone CPP induces sex-dependent redistributions of opioid receptors in hippocampal circuits in a manner facilitating opioid-associative learning processes and may help explain the increased susceptibility of females to opioid addiction acquisition and relapse.
-
Neurotransmitter and headache target localization in the trigeminal ganglia (TG) might increase the understanding of sites of action, and mechanisms related to headache therapy. The overall aim of the study was to investigate the presence of migraine targets in the TG with particular emphasis on pituitary adenylate cyclase-activating peptide (PACAP) and calcitonin gene-related peptide (CGRP), known to be involved in cranial pain processing, and selected headache targets. Rat- and human TG were processed for immunohistochemistry. ⋯ Occasionally, PACAP-38-positive cells also expressed VPAC1, SNAP25 and SV2-A. VPAC1 was generally detected in SGCs enveloping PACAP-38-positive and -negative neuronal somas. Our study revealed potential sites of actions for anti-headache drugs such as PACAP receptor antagonists, Lasmiditan (5-HT1F agonist) and Botox (blocks exocytosis through SV2-A/SNAP25) in rat and human TG and considerable overlap between species in expression to specific cell types, except for VPAC1 and SNAP25.
-
Prescription opioid abuse, for example of oxycodone, is a pressing public health issue. This study focuses on how chronic oxycodone self-administration (SA) affects the reward pathways in the mouse brain. In this study, we tested the hypothesis that the expression of reward-related genes in the ventral and dorsal striatum, areas involved in different aspects of opioid addiction models, was altered within 1 h after chronic oxycodone SA, using transcriptome-wide sequencing (RNA-seq). ⋯ Some genes detected by RNA-seq were confirmed by quantitative polymerase chain reaction (qPCR). Conclusion: A RNA-seq study shows that chronic oxycodone SA alters the expression of several reward-related genes in the dorsal and ventral striatum. These results suggest potential mechanisms underlying neuronal adaptation to chronic oxycodone self-exposure, of relevance to our mechanistic understanding of prescription opioid abuse.
-
The present study set out to assess the possible role of the medial prefrontal cortex (mPFC) cannabinoid CB1 receptors and BDNF/cFOS signaling pathways in morphine-dextromethorphan (DXM) cross state-dependent memory (SDM) using male Wistar rats. Changes on the levels of BDNF and cFOS proteins in the PFC were examined by Western blot analysis. Present results revealed that levels of BDNF and cFOS proteins were significantly increased in the animals that were trained in the passive avoidance apparatus. ⋯ Interestingly, pre-test intra-mPFC injections of ACPA inhibited cross-SDM between the drugs which was associated with an elevation of BDNF expression in the PFC. Additionally, pre-test administration of an ineffective dose of DXM (10 mg/kg, i.p.) could not reverse morphine-induced memory loss, while pre-test intra-mPFC injections of AM-251 potentiated morphine-DXM cross-SDM. Taken together, it can be concluded that mPFC through CB1cannabinoid receptors has a critical role in morphine-DXM cross-SDM which may be associated with the PFC BDNF/cFOS signaling pathway.
-
Pathological Tau (P-Tau) leads to dementia and neurodegeneration in tauopathies, including Alzheimer's disease. The P301L transgenic mice well mimic human tauopathy features; P-Tau localizes also at the dendritic spine level and this correlates with synaptic markers down-regulation. Importantly, tg females present a more severe pathology compared to male mice. ⋯ These results suggest that JNK plays a key role in synaptopathy of P301L mice. Importantly, until now, there are any efficient treatments against synaptic pathology and JNK could represent an interesting target to tackle P-Tau-induced synaptic pathology. It will be important to test specific JNK inhibitors to verify their potential neuroprotective effect.