Disulfiram Produces Potent Anxiolytic-Like Effects Without Benzodiazepine Anxiolytics-Related Adverse Effects in Mice

Discriminative stimulus and reinforcing effects of diclazepam in rodents

Diclazepam, a designer benzodiazepine, is a lesser-known novel anxiolytic substance and a structural analog of diazepam. Although several case studies have reported the adverse effects of diclazepam, their potential impacts remain unknown. Therefore, this study aimed to determine the effects of diclazepam in rodents using drug discrimination, locomotor activity, self-administration (SA), and conditioned place preference (CPP) tests. Sprague-Dawley rats (male, 8 weeks old, weighing 220-450 g, n = 12 per group) and C57BL/6 mice (male, 7 weeks old, weighing 20-25 g, n = 7-8 per group) were administered alprazolam, morphine, and diclazepam. Diclazepam fully elicited alprazolam-appropriate dose-dependent lever responses (>80 %) similar to those of alprazolam. In rats administered 0.5 mg/kg of morphine, a partial substitution (80 %-20 %) was observed. Mice receiving intraperitoneal injections of diclazepam (0.05, 0.2, and 2 mg/kg) showed decreased locomotor activity. In the SA experiment, mice that self-administered intravenous diclazepam (2 μg/kg/infusion) showed significantly higher infusion and active lever responses compared to the vehicle group. No statistically significant rewarding effects of diclazepam at the doses of 0.2 and 2 mg/kg evaluated using the CPP paradigm were found. In conclusion, diclazepam has reinforcing effects and shares the interoceptive effects of alprazolam. Therefore, legal restrictions on the use of diclazepam should be carefully considered.

Multiple factors contribute to flight behaviors during fear conditioning

Shifting defensive mode from one to another by the imminence of threat is crucial for survival. The transition of defensive mode from freezing to flight is observed during the modified fear conditioning, however, the flight during fear conditioning is not well characterized. To characterize the flight behaviors during the fear conditioning, we conducted experiments in male mice focusing on the influence of the context, the intensity of the unconditioned stimulus and conditioned stimulus (CS), the schedule of conditioning, and the state of the subject. Flight behaviors triggered by salient CS showed characteristics of fear-potentiated defensive behaviors depending on the conditioned context, while repetitive conditioning enhanced the expression of the flight and developed an association between the CS and the flight. The salient auditory stimulus was the primary factor to trigger flight behaviors. Also, the spaced conditioning increased the expression of flight behaviors. Taken together, the flight behavior during fear conditioning is not a simple conditioned response nor simple fear-potentiated behavior, but a complicated mixture of multiple components of defensive behaviors. The transition of defensive mode could be induced by the integration of multiple innate and learned components of fear or anxiety.

Inhibition of the chemokine signal regulator FROUNT by disulfiram ameliorates crescentic glomerulonephritis

Activated monocytes/macrophages promote glomerular injury, including crescent formation, in anti-glomerular basement membrane (GBM) glomerulonephritis. Disulfiram, an alcohol-aversion drug, inhibits monocyte/macrophage migration by inhibiting FROUNT, a cytosolic protein that enhances chemokine receptor signaling. Our study found that disulfiram at a human equivalent dose successfully blocked albuminuria and crescent formation with podocyte loss, and later stage kidney fibrotic lesions, in a rat model of anti-GBM glomerulonephritis. A disulfiram derivative, DSF-41, with more potent FROUNT inhibition activity, inhibited glomerulonephritis at a lower dose than disulfiram. Disulfiram markedly reduced the number of monocytes or macrophages at the early stage of glomerulonephritis and that of CD3⁺ and CD8⁺ lymphocytes at the established stage. Impaired pseudopodia formation was observed in the glomerular monocytes/macrophages of the disulfiram group; consistent with the in vitro observation that disulfiram blocked chemokine-dependent pseudopodia formation and chemotaxis of bone marrow-derived monocytes/macrophages. Furthermore, disulfiram suppressed macrophage activation as revealed by reduced expression of inflammatory cytokines and chemokines (TNF-α, CCL2, and CXCL9) and reduced CD86 and MHC class II expressions in monocytes/macrophages during glomerulonephritis. The dramatic reduction in monocyte/macrophage number might have resulted from disulfiram suppression of both the chemotactic response of monocytes/macrophages and their subsequent activation to produce cytokines and chemokines, which further recruit monocytes. Additionally, FROUNT was expressed in CD68⁺ monocytes/macrophages infiltrating the crescentic glomeruli in human anti-GBM glomerulonephritis. Thus, disulfiram can be a highly effective and safe drug for the treatment of glomerulonephritis by blocking the chemotactic responses of monocytes/macrophages and their activation status in the glomerulus.