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Big conductance calcium-activated potassium channel openers control spasticity without sedation

Baker, D; Pryce, G; Visintin, C; Sisay, S; Bondarenko, AI; Ho, WSV; Jackson, SJ; ... Selwood, DL; + view all (2017) Big conductance calcium-activated potassium channel openers control spasticity without sedation. British Journal of Pharmacology , 174 (16) pp. 2662-2681. 10.1111/bph.13889. Green open access

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Abstract

BACKGROUND AND PURPOSE: Our initial aim was to generate cannabinoid agents that control spasticity, occurring as a consequence of multiple sclerosis (MS), whilst avoiding the sedative side effects associated with cannabis. VSN16R was synthesized as an anandamide (endocannabinoid) analogue in an anti-metabolite approach to identify drugs that target spasticity. EXPERIMENTAL APPROACH: Following the initial chemistry, a variety of biochemical, pharmacological and electrophysiological approaches, using isolated cells, tissue-based assays and in vivo animal models, were used to demonstrate the activity, efficacy, pharmacokinetics and mechanism of action of VSN16R. Toxicological and safety studies were performed in animals and humans. KEY RESULTS: VSN16R had nanomolar activity in tissue-based, functional assays and dose-dependently inhibited spasticity in a mouse experimental encephalomyelitis model of MS. This effect occurred with over 1000-fold therapeutic window, without affecting normal muscle tone. Efficacy was achieved at plasma levels that are feasible and safe in humans. VSN16R did not bind to known CB1/CB2/GPPR55 cannabinoid-related receptors in receptor-based assays but acted on a vascular cannabinoid target. This was identified as the major neuronal form of the big conductance, calcium-activated potassium (BKCa) channel. Drug-induced opening of neuronal BKCa channels induced membrane hyperpolarization, limiting excessive neural-excitability and controlling spasticity. CONCLUSIONS AND IMPLICATIONS: We identified the neuronal form of the BKCa channel as the target for VSN16R and demonstrated that its activation alleviates neuronal excitability and spasticity in an experimental model of MS, revealing a novel mechanism to control spasticity. VSN16R is a potential, safe and selective ligand for controlling neural hyper-excitability in spasticity.

Type: Article
Title: Big conductance calcium-activated potassium channel openers control spasticity without sedation
Open access status: An open access version is available from UCL Discovery
DOI: 10.1111/bph.13889
Publisher version: http://dx.doi.org/10.1111/bph.13889
Language: English
Additional information: © 2017 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Keywords: Science & Technology, Life Sciences & Biomedicine, Pharmacology & Pharmacy, N-ARACHIDONOYL GLYCINE, MULTIPLE-SCLEROSIS MODEL, GATED ION CHANNELS, CANNABINOID RECEPTOR, CONCISE GUIDE, INTERNATIONAL UNION, MOLECULAR-MECHANISM, NEUROPATHIC PAIN, BKCA CHANNELS, BETA-SUBUNIT
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UK Dementia Research Institute HQ
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine > Wolfson Inst for Biomedical Research
UCL > Provost and Vice Provost Offices > VP: Health
UCL > Provost and Vice Provost Offices > VP: Health > Translational Research Office
URI: https://discovery.ucl.ac.uk/id/eprint/1569153
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