1. Descending serotonergic and noradrenergic systems do not regulate the antipruritic effects of cannabinoids
- Author
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Cetin Hakan Karadag, Zeynep Gizem Todurga, Ahmet Ulugol, and Ozgur Gunduz
- Subjects
0301 basic medicine ,Agonist ,Serotonin ,medicine.drug_class ,Morpholines ,medicine.medical_treatment ,5,7-Dihydroxytryptamine ,Naphthalenes ,Pharmacology ,Serotonergic ,Mice ,Norepinephrine ,03 medical and health sciences ,0302 clinical medicine ,Neural Pathways ,medicine ,Animals ,Oxidopamine ,WIN 55,212-2 ,Biological Psychiatry ,Antipruritic ,Cannabinoid Receptor Agonists ,Mice, Inbred BALB C ,Dose-Response Relationship, Drug ,business.industry ,Pruritus ,Antipruritic Effect ,Antipruritics ,Scratching ,Benzoxazines ,Psychiatry and Mental health ,030104 developmental biology ,Spinal Cord ,Cannabinoid ,business ,030217 neurology & neurosurgery ,medicine.drug - Abstract
BackgroundFor centuries, cannabinoids have been known to be effective in pain states. Itch and pain are two sensations sharing a lot in common.ObjectiveThe 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 methodsScratching behaviour was induced by intradermal injection of serotonin (50 µg/50 µl/mouse) to Balb/c mice. The neurotoxins 5,7-dihydroxytryptamine (5,7-DHT, 50 μg/mouse) and 6-hydroxydopamine (6-OHDA, 20 μg/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.ConclusionOur findings indicate that cannabinoids dose-dependently reduce serotonin-induced scratching behaviour and neurotoxic destruction of descending inhibitory pathways does not mediate this antipruritic effect.
- Published
- 2016