Tetraethylammonium, glibenclamide, and 4-aminopyridine modulate post-occlusive reactive hyperemia in non-glabrous human skin with no roles of NOS and COX.

Post-occlusive reactive hyperemia (PORH) following arterial occlusion is widely used to assess cutaneous microvascular function, though the underlying mechanisms remain to be fully elucidated. We evaluated the hypothesis that Ca2+ -activated, ATP-sensitive, and voltage-gated K+ channels (KC a , KATP , and KV channels, respectively) contribute to PORH while nitric oxide synthase (NOS) and cyclooxygenase (COX) do not. On separate occasions, cutaneous blood flow (laser Doppler flowmetry) was monitored before and following 5-min arterial occlusion at forearm skin sites treated via microdialysis with the following: Experiment 1 (n = 11): (a) lactated Ringer solution (Control), (b) 10 mM Nω -nitro-L -arginine (NOS inhibitor), (c) 10 mM ketorolac (COX inhibitor), and (d) combined NOS+COX inhibition; Experiment 2 (n = 14): (a) lactated Ringer solution (Control), (b) 50 mM tetraethylammonium (non-selective KC a channel blocker), (c) 5 mM glibenclamide (non-specific KATP channel blocker), and (d) 10 mM 4-aminopyridine (non-selective KV channel blocker). Separate and combined NOS and COX inhibition did not influence PORH. Conversely, tetraethylammonium and glibenclamide attenuated, whereas 4-aminopyridine augmented PORH. We showed that tetraethylammonium, glibenclamide, and 4-aminopyridine modulate PORH with no roles of NOS and COX in human non-glabrous forearm skin in vivo. Thus, cutaneous PORH changes could reflect altered K+ channel function. © 2019 John Wiley & Sons Ltd.

Citation

Naoto Fujii, Gregory W McGarr, Masashi Ichinose, Takeshi Nishiyasu, Glen P Kenny. Tetraethylammonium, glibenclamide, and 4-aminopyridine modulate post-occlusive reactive hyperemia in non-glabrous human skin with no roles of NOS and COX. Microcirculation (New York, N.Y. : 1994). 2020 Jan;27(1):e12586

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PMID: 31435995

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