Competitive\nAntagonism of Xylazine on α7 Nicotinic\nAcetylcholine Receptors and Reversal by Curcuminoids

Co-use of xylazine with opioids is a major health threat\nin the\nUnited States. However, a critical knowledge gap exists in the understanding\nof xylazine-induced pharmacological and pathological impact. Xylazine\nis mostly known as an agonist of α2-adrenergic receptors (α2-ARs),\nbut its deleterious effects on humans cannot be fully reversed by\nthe α2-AR antagonists, suggesting the possibility that xylazine\ntargets receptors other than α2-ARs. Here, we report the discovery\nof α7 nicotinic acetylcholine receptors (α7 nAChRs) as\ntargets of xylazine. In Xenopus oocytes\nexpressing α7 nAChRs, xylazine competitively antagonizes channel\ncurrents elicited by the agonist acetylcholine. In PC12 cells, xylazine\nsuppresses choline-stimulated intracellular calcium ([Ca<sup>2+</sup>]<sub>in</sub>) transients that are mediated by endogenously expressed\nα7 nAChRs. Furthermore, we find that curcuminoids, ivermectin,\nand the α7-specific positive allosteric modulator PNU120596\ncan effectively offset the xylazine inhibition of α7 nAChRs.\nConsidering the prominent role of α7 nAChRs in the cholinergic\nanti-inflammatory pathway and wide expression in the human body, our\nfindings present a potential new strategy to reverse xylazine-caused\ndamage using curcuminoids or repurposing ivermectin. This α7\nnAChR-focused strategy may offer an immediate deployment that is likely\neffective in improving xylazine-related treatment outcomes.