# Levamisole Impairs Vascular Function by Blocking α-Adrenergic Receptors and Reducing NO Bioavailability in Rabbit Renal Artery

## TL;DR

Levamisole, a drug found in adulterated cocaine, harms kidney blood flow by blocking receptors and reducing nitric oxide in rabbit arteries.

## Contribution

This study reveals that levamisole impairs vascular function via α-adrenergic receptor blockade and oxidative stress in renal arteries.

## Key findings

- Levamisole acts as a non-selective α-adrenergic receptor blocker and reduces α1-adrenoceptor expression.
- Levamisole impairs endothelium-dependent relaxation without affecting eNOS expression.
- Superoxide dismutase partially prevents levamisole-induced vascular dysfunction, indicating oxidative stress involvement.

## Abstract

Levamisole is an anthelmintic drug restricted to veterinary use but is currently detected as the most widely used cocaine cutting agent in European countries. Levamisole-adulterated cocaine has been linked to acute kidney injury, marked by a decrease in glomerular filtration rate, which involves reduced renal blood flow, but data on the alteration of renovascular response produced by levamisole are scarce. Renal arteries were isolated from healthy rabbits and used for isometric tension recording in organ baths and protein analysis. We provide evidence that depending on its concentration, levamisole modulates renovascular tone by acting as a non-selective α-adrenergic receptor blocker and down-regulates α1-adrenoceptor expression. Furthermore, levamisole impairs the endothelium-dependent relaxation induced by acetylcholine without modifying endothelial nitric oxide synthase (eNOS) expression. However, exposure to superoxide dismutase (SOD) partially prevents the impairment of ACh-induced relaxation by levamisole. This response is consistent with a down-regulation of SOD1 and an up-regulation of NADPH oxidase 4 (Nox4), suggesting that endothelial NO loss is due to increased local oxidative stress. Our findings demonstrate that levamisole can interfere with renal blood flow and the coordinated response to a vasodilator stimulus, which could worsen the deleterious consequences of cocaine use.

EFS electric field stimulation, NA noradrenaline, AR adrenergic receptor, IP3 inositol 1, 4, 5-trisphosphate, cAMP cyclic adenosine monophosphate, mAChR muscarinic acetylcholine receptor, eNOS endothelial nitric oxide synthase, sGC soluble guanylyl cyclase, SOD superoxide dismutase, NOX4 NAPH oxidase 4