Non-Painful Peripheral Inflammation Blocks Conditioned Place-Preference to Morphine and Nicotine through an Ibuprofen-Sensitive and an Ibuprofen Insensitive Pathway

The field of neuroimmunology has expanded in recent years providing new insights and therapies into pathologies like stroke, autism, and depression. However, few works explore the relationship between inflammatory stimuli and motivation. Thus, the aim of this study was to determine how non-painful inflammatory stimuli affect reward. To test reward-response, we used the morphine and the nicotine induced conditioned place-preference and place-aversion model in rats with non-painful inflammation. The following inflammatory models were used: non-painful infectious inflammation: 24 hrs prior to conditioning sessions, an injection with Calmette-Guerin bacillus (CGB) 1 × 107 cfu, ip, was administered. Non-painful non-infectious inflammation: 24 hrs prior to conditioning sessions, rats’ sciatic nerve was blocked and cut, followed by the injection of carrageenan (750 μl) in the paw. We then measured the cytokine concentration to determine the inflammatory profile of each of our models. Finally, we administered ibuprofen to determine if it could prevent the effect of inflammation over conditioned place-preference. We show that carrageenan significantly reduced the morphine-induced reward. Non-painful inflammatory stimulus, CGB and denervation + carrageenan, inhibit the conditioned place-preference to morphine and nicotine, CGB also block conditioned place-aversion to nicotine;carrageenan has no effect on CPA. The administration of ibuprofen reinstates conditioned place-preference to morphine and nicotine in the carrageenan model, but has no effect in the CGB model;finally ibuprofen has no effect on CPA. Our data suggest that non-painful-inflammatory stimuli inhibit the reward system, independent of cytokine concentration. Furthermore, the administration of a PGE 2 inhibitor can importantly modulate this phenomenon.

Phenotypic heterogeneity in amyotrophic lateral sclerosis type 8 and modifying mechanisms of neurodegeneration

In his accounts "On longevity and shortness of life", Aristotle considered how diseased states could be interchangeably associated with long and short lifespans. He believed that the presence of opposite elements and the environment were the sole determinants of this variability.

NSAID celecoxib: a potent mitochondrial pro-oxidant cytotoxic agent sensitizing metastatic cancers and cancer stem cells to chemotherapy

Intermittent hypoxia within tumor microenvironments causes pro-oxidative stress impairing oxidative phos-phorylation(OxPhos)and increases mitochondrial production of reactive oxygen species(ROS).In primary tu-mors this provokes metabolic reprogramming of both tumor cells and cancer stem cells and emergence of highly metastatic cancer cells.Tumor reprogramming is initiated by activating nuclear respiratory factors and hypoxia-inducible factors in response to changes in oxygen and ROS levels.Hence,hypoxia-induced pro-oxidative stress drives invasion and metastasis.However,it is also the Achilles’heel of metastatic cancer cells because pro-oxi-dative agents further overload the mitochondria and intracellular milieu with excessive ROS to trigger apoptosis,whereas antioxidant agents promote their survival and tumor progression.Herein lies the metastatic tumor cell sensitivity to non-steroidal anti-inflammatory drugs(NSAIDs)and we and others have shown that the NSAID celecoxib exerts powerful pro-oxidative anticancer effects by directly targeting mitochondria to increase ROS production and trigger cancer cell death,including metastatic cancer cells and cancer stem cells.This review highlights the considerable benefits from appropriate NSAID use in humans against post-diagnosis metastatic tumors and the need to further develop their use as adjuvant therapy for advanced stage metastatic disease where they are already showing significantly improved clinical outcomes.