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bioRxiv · 10.1101/731943

Structure-activity relationship studies of three novel 4-aminopyridine K+ channel blockers

Rodriguez-Rangel, S.·Bravin, A. D.·Ramos-Torres, K. M.·Brugarolas, P.·Sanchez-Rodriguez, J. E.
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Abstract

4-Aminopyridine (4AP) is a specific blocker of voltage-gated potassium channels (KV1 family) clinically approved for the symptomatic treatment of patients with multiple sclerosis (MS). It has recently been shown that [18F]3F4AP, a radiofluorinated analog of 4AP, also binds to KV1 channels and can be used as a PET tracer for the detection of demyelinated lesions in rodent models of MS. Here, we investigate three novel 4AP derivatives containing methyl (-CH3), methoxy (-OCH3) and trifluoromethyl (-CF3) in the 3 position as potential candidates for PET imaging and/or therapy. We characterized the physicochemical properties of these compounds (pKa and logD) and analyzed their ability to block Shaker K+ channel under different voltage and pH conditions. Our results demonstrate that all three derivatives are able to block voltage-gated potassium channels. Specifically, 3-methyl-4-aminopyridine (3Me4AP) was found to be approximately 7-fold more potent than 4AP, whereas the methoxy (3MeO4AP) and trifluoromethyl (3CF34AP) containing compounds were about 3- to 4-fold less potent than 4AP, respectively. These results suggest that these novel derivatives are potential candidates for therapy and imaging.

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Rodriguez-Rangel, S., Bravin, A. D., Ramos-Torres, K. M., Brugarolas, P., Sanchez-Rodriguez, J. E.. 2019-08-11. Structure-activity relationship studies of three novel 4-aminopyridine K+ channel blockers. https://doi.org/10.1101/731943

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