Lithium attenuates d-amphetamine-induced hyperlocomotor activity in mice via inhibition of interaction between cyclooxygenase-2 and indoleamine-2,3-dioxygenase

P2X7 receptor inhibition alleviates mania-like behavior independently of interleukin-1β

Purinergic dysfunctions are associated with mania and depression pathogenesis. P2X7 receptor (P2X7R) mediates the IL-1β maturation via NLRP3 inflammasome activation. We tested in a mouse model of the subchronic amphetamine (AMPH)-induced hyperactivity whether P2X7R inhibition alleviated mania-like behavior through IL-1β. Treatment with JNJ-47965567, a P2X7R antagonist, abolished AMPH-induced hyperlocomotion in wild-type and IL-1α/β-knockout male mice. The NLRP3 inhibitor MCC950 failed to reduce AMPH-induced locomotion in WT mice, whereas the IL-1 receptor antagonist anakinra slightly increased it. AMPH increased IL-10, TNF-α, and TBARS levels, but did not influence BDNF levels, serotonin, dopamine, and noradrenaline content in brain tissues in either genotypes. JNJ-47965567 and P2rx7-gene deficiency, but not IL-1α/β-gene deficiency, attenuated AMPH-induced [3H]dopamine release from striatal slices. In wild-type and IL-1α/β-knockout female mice, JNJ-47965567 was also effective in attenuating AMPH-induced hyperlocomotion. This study suggests that AMPH-induced hyperactivity is modulated by P2X7Rs, but not through IL-1β.

The Protective Effect of Lithium Against Rotenone may be Evolutionarily Conserved: Evidence from Eisenia fetida, a Primitive Animal with a Ganglionic Brain

Chronic exposure to stress is a non-adaptive situation that is associated with mitochondrial dysfunction and the accumulation of reactive oxygen species (ROS), especially superoxide anion (SA). This accumulation of ROS produces damage-associated molecular patterns (DAMPs), which activate chronic inflammatory states and behavioral changes found in several mood disorders. In a previous study, we observed that an imbalance of SA triggered by rotenone (Ro) exposure caused evolutionarily conserved oxi-inflammatory disturbances and behavioral changes in Eisenia fetida earthworms. These results supported our hypothesis that SA imbalance triggered by Ro exposure could be attenuated by lithium carbonate (LC), which has anti-inflammatory properties. The initial protocol exposed earthworms to Ro (30 nM) and four different LC concentrations. LC at a concentration of 12.85 mg/L decreased SA and nitric oxide (NO) levels and was chosen to perform complementary assays: (1) neuromuscular damage evaluated by optical and scanning electron microscopy (SEM), (2) innate immune inefficiency by analysis of Eisenia spp. extracellular neutrophil traps (eNETs), and (3) behavioral changes. Gene expression was also evaluated involving mitochondrial (COII, ND1), inflammatory (EaTLR, AMP), and neuronal transmission (nAchR α5). LC attenuated the high melanized deposits in the circular musculature, fiber disarrangement, destruction of secretory glands, immune inefficiency, and impulsive behavior pattern triggered by Ro exposure. However, the effects of LC and Ro on gene expression were more heterogeneous. In summary, SA imbalance, potentially associated with mitochondrial dysfunction, appears to be an evolutionary component triggering oxidative, inflammatory, and behavioral changes observed in psychiatric disorders that are inhibited by LC exposure.

Mood and behavior regulation: interaction of lithium and dopaminergic system

Lithium is one of the most effect mood-stabilizing drugs prescribed especially for bipolar disorder. Lithium has wide range effects on different molecular factors and neural transmission including dopaminergic signaling. On the other hand, mesolimbic and mesocortical dopaminergic signaling is significantly involved in the pathophysiology of neuropsychiatric disorders. This review article aims to study lithium therapeutic mechanisms, dopaminergic signaling, and the interaction of lithium and dopamine. We concluded that acute and chronic lithium treatments often reduce dopamine synthesis and level in the brain. However, some studies have reported conflicting results following lithium treatment, especially chronic treatment. The dosage, duration, and type of lithium administration, and the brain region selected for measuring dopamine level were not significant differences in different chronic treatments used in previous studies. It was suggested that lithium has various mechanisms affecting dopaminergic signaling and mood, and that many molecular factors can be involved, including brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), β-catenin, protein kinase B (Akt), and glycogen synthase kinase-3 beta (GSK-3β). Thus, molecular effects of lithium can be the most important mechanisms of lithium that also alter neural transmissions including dopaminergic signaling in mesolimbic and mesocortical pathways.

Role of Microglia in Psychostimulant Addiction

The use of psychostimulant drugs can modify brain function by inducing changes in the reward system, mainly due to alterations in dopaminergic and glutamatergic transmissions in the mesocorticolimbic pathway. However, the etiopathogenesis of addiction is a much more complex process. Previous data have suggested that microglia and other immune cells are involved in events associated with neuroplasticity and memory, which are phenomena that also occur in addiction. Nevertheless, how dependent is the development of addiction on the activity of these cells? Although the mechanisms are not known, some pathways may be involved. Recent data have shown psychoactive substances may act directly on immune cells, alter their functions and induce various inflammatory mediators that modulate synaptic activity. These could, in turn, be involved in the pathological alterations that occur in substance use disorder. Here, we extensively review the studies demonstrating how cocaine and amphetamines modulate microglial number, morphology, and function. We also describe the effect of these substances in the production of inflammatory mediators and a possible involvement of some molecular signaling pathways, such as the toll-like receptor 4. Although the literature in this field is scarce, this review compiles the knowledge on the neuroimmune axis that is involved in the pathogenesis of addiction, and suggests some pharmacological targets for the development of pharmacotherapy.