Assessment of Acute Motor Effects and Tolerance Following Self-Administration of Alcohol and Edible ∆9 -Tetrahydrocannabinol in Adolescent Male Mice

The synthetic cannabinoid WIN 55,212-2 attenuates cognitive and motor deficits and reduces amyloid load in 5XFAD Alzheimer mice

BACKGROUND

Alzheimer's disease (AD) is characterized by cognitive decline, with pathological features including amyloid β (Aβ) plaques and inflammation. Despite recent approvals of anti-amyloid antibodies, there remains a need for disease-modifying and easily accessible therapies. The endocannabinoid system presents a promising target for AD treatment, as it regulates various processes implicated in AD pathogenesis.

AIMS

This study assesses the effects of the synthetic cannabinoid WIN 55,212-2 on AD pathology and behavior deficits in aged 5XFAD mice, a well-established AD model.

METHODS

Male 9-month-old 5XFAD mice received either 0.2 mg/kg WIN 55,212-2 or a vehicle solution for 42 days. Memory, anxiety, and motor tests were conducted at 10 months to identify potential changes in behavior and cognition following WIN 55,212-2 treatment. Additionally, the effects of prolonged WIN 55,212-2 treatment on Aβ pathology and neuroinflammation in the brain were quantified immunohistochemically.

RESULTS

Therapeutic WIN 55,212-2 treatment improved the motor performance of 5XFAD mice on the rotarod and rescued memory deficits in the water maze. However, WIN 55,212-2 treatment did not significantly affect anxiety-like behavior in 5XFAD mice. Additionally, prolonged treatment with WIN 55,212-2 reduced Aβ plaque pathology and astrogliosis in the cortex and hippocampus.

CONCLUSIONS

This study highlights the therapeutic potential of WIN 55,212-2 in AD by ameliorating cognitive and motor deficits and reducing neuropathology. These findings support a cannabinoid-based therapy as a promising strategy for AD treatment, with WIN 55,212-2 emerging as a potential candidate.

Effects of ethanol on mechanical allodynia and dynamic weight bearing in male and female mice with spared nerve injury

BACKGROUND

Men and women with chronic pain report increased alcohol use and are more likely to be diagnosed with alcohol use disorder. The relationship between alcohol use and pain is bidirectional. Alcohol is used as an analgesic, but chronic alcohol intake increases pain. Sex differences in the relationship between chronic pain and alcohol are reported in the clinical and preclinical literature, but due to this bidirectional relationship, it is challenging to investigate the mechanisms that contribute to these differences. Thus, animal models of chronic pain are needed to characterize the efficacy of ethanol as an analgesic in males and females. The current experiments tested the hypothesis that ethanol differentially reduces pain behaviors in male and female mice in chronic neuropathic pain.

METHODS

The spared nerve injury (SNI) model was used to investigate the analgesic effects of multiple doses of ethanol (0.5, 1, 2, g/kg i.p.) in male and female mice using von Frey and dynamic weight-bearing (DWB) assays.

RESULTS

In both male and female mice, SNI led to robust allodynia and shifts in dynamic weight bearing. In male SNI mice, all three doses of ethanol fully reversed mechanical allodynia and shifts in DWB. In SNI females, only the highest dose (2.0 g/kg) was fully antiallodynic in the von Frey assay, while shifts in weight bearing were reversed at the 1.0 and 2.0 g/kg doses. The differences between male and females were not due to lower blood ethanol concentrations in female mice.

CONCLUSION

These data indicate that while ethanol has antiallodynic and antinociceptive effects in male and female mice, the doses and time course of these effects are distinct. Studies investigating the relationship between pain and ethanol exposure in mice should consider sex as a key variable. These data also inform reported sex differences in rodent models of chronic pain and in chronic pain patients.