Volume 11, Issue 4 (July & August - Special Issue on Memory, Reward & Stress 2020)                   BCN 2020, 11(4): 473-480 | Back to browse issues page

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1- Department of Medical Pharmacology, Faculty of Medicine, Trakya University, Turkey.
Introduction: For centuries, cannabinoids are known to be effective in pain relief. Itch is an unpleasant sensation that provokes a desire to scratch. Since itch and pain are two sensations sharing a lot in common, we aimed to investigate whether the cannabinoid agonist WIN 55,212-2 reduces serotonin-induced scratching behavior and also observe whether modulation of nitric oxide (NO) production mediates the antipruritic effect of WIN 55,212-2.
Methods: Scratching behavior is induced by intradermal injection of serotonin (50 µg/50 µL/mouse) to BALB/c mice. The cannabinoid agonist WIN 55,212-2 (1, 3, 10 mg/kg, IP) was given 30 min before serotonin injection. To observe the effect of NO modulation on the antipruritic effect of cannabinoids, the endothelial nitric oxide synthase (NOS) inhibitor L-NAME (3 mg/kg, IP), the neuronal NOS inhibitor 7-nitroindazole (3 mg/kg, IP), and the NO precursor L-arginine (100 mg/kg, IP) were administered together with WIN 55,212-2. 
Results: WIN 55,212-2 reduced serotonin-induced scratches at higher doses (3, 10 mg/kg; P<0.0001). The endothelial NOS inhibitor L-NAME, the neuronal NOS inhibitor 7-nitroindazole, and the nitric oxide precursor L-arginine did not influence the antipruritic action of WIN 55,212-2. When NO modulators were used alone, only the neuronal NOS inhibitor 7-nitroindazole attenuated serotonin-induced scratches (P<0.0001).
Conclusion: Our findings indicate that exogenous cannabinoids may attenuate serotonin-induced scratches and NO does not mediate the antipruritic effect of WIN 55,212-2. On the other hand, neuronal NOS inhibition may play a role in the production of serotonin-induced scratches.
Type of Study: Original | Subject: Behavioral Neuroscience
Received: 2018/03/30 | Accepted: 2019/04/29 | Published: 2020/07/1

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