Objective: This study evaluated the anxiolytic effects of CBD, THC, and their combination in a reserpine-induced Parkinson’s mouse model using the Elevated Plus Maze (EPM)

Background: Anxiety is a prevalent non-motor symptom in Parkinson’s disease (PD), often preceding the onset of motor impairments. The involvement of serotonergic, dopaminergic, and endocannabinoid systems in anxiety provides a rationale for investigating phytocannabinoids such as cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (THC) in PD models

Method: Forty-two adult mice were divided into seven groups (n=6). Group I (normal control) was treated with 10 ml/kg of distilled water, Group II was administered reserpine (0.5 mg/kg i.p. for 10 days) to induce Parkinson-like symptoms. Groups III–VII received reserpine followed by post-treatment with CBD (30 or 60 mg/kg), THC (4 or 6 mg/kg), or a combination of CBD (60 mg/kg) and THC (6 mg/kg) for 14 days. Anxiety-like behaviour was assessed using the Elevated Plus Maze, focusing on the percentage time spent in open arms and percentage entries into the open arms which gave rise to the index of open arm avoidance.

Results: Reserpine significantly increased anxiety-like behaviour, with a marked increase in open-arm avoidance (96.25 ± 3.75 %) compared to the control group (67.25 ± 1.44 %). Post-treatment with CBD (30 mg/kg: 71.75 ± 0.85 %, 60 mg/kg: 68.50 ± 1.66 %) and THC (4 mg/kg: 61.25 ± 4.13 %, 6 mg/kg: 69.25 ± 5.63 %) significantly reduced the open-arm avoidance compared to the reserpine group (96.25 ± 3.75 %). The combination group (70.25 ± 0.85 %) showed a significant decrease in open arm avoidance, comparable to control group (67.25 ± 1.44 %)

Conclusion: Both CBD and THC individually and in combination exhibited anxiolytic effects in the PD mouse model. These findings support the potential of cannabinoid-based interventions in the management of PD-associated anxiety.

Table 1

Figure 1

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