Descending serotonergic and noradrenergic systems do not regulate the antipruritic effects of cannabinoids

作者：Todurga Zeynep Gizem; Gunduz Ozgur; Karadag Cetin Hakan; Ulugol Ahmet^*

来源：ACTA NEUROPSYCHIATRICA, 2016, 28(6): 321-326.

DOI：10.1017/neu.2016.16

• cannabinoid system
• descending inhibition
• WIN 55,212-2
• pruritus

Background: For centuries, cannabinoids have been known to be effective in pain states. Itch and pain are two sensations sharing a lot in common.
Objective: The goal of this research was to observe whether the cannabinoid agonist WIN 55,212-2 reduces serotonin-induced scratching behaviour and whether neurotoxic destruction of descending serotonergic and noradrenergic pathways mediate the antipruritic effect of WIN 55,212-2.
Material and methods: Scratching behaviour was induced by intradermal injection of serotonin (50 mu g/50 mu l/mouse) to Balb/c mice. The neurotoxins 5,7-dihydroxytryptamine (5,7-DHT, 50 mu g/mouse) and 6-hydroxydopamine (6-OHDA, 20 mu g/mouse) are applied intrathecally to deplete serotonin and noradrenaline in the spinal cord. WIN 55,212-2 (1, 3, 10 mg/kg, i.p.) dose-dependently attenuated serotonin-induced scratches. Neurotoxic destruction of neither the serotonergic nor the noradrenergic systems by 5,7-DHT and 6-OHDA, respectively, had any effect on the antipruritic action of WIN 55,212-2.
Conclusion: Our findings indicate that cannabinoids dose-dependently reduce serotonin-induced scratching behaviour and neurotoxic destruction of descending inhibitory pathways does not mediate this antipruritic effect.

• 出版日期2016-12