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Polymyxin B, a novel inhibitor of red cell Ca 2+ ‐activated K + channel
Author(s) -
Varec̆ka L̆udovít,
Peterajová Elena,
Pogády Jozef
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)81152-3
Subject(s) - polymyxin b , chemistry , biophysics , efflux , propranolol , biochemistry , biology , antibiotics , endocrinology
Polymyxin B (PXB), a cyclic peptide antibiotic, in concentrations 0.1–3.0 mg/ml (0.08–4.0 mmol/l), inhibited the K + efflux induced by opening of the Ca 2+ ‐activated K + channel (the Gárdos effect) in intact human red blood cells. The inhibition was observed when the Gárdos effect was elicited by Ca 2+ in the presence of vandate, or propranolol, in ATP‐depleted cells, and in A23187‐treated cells. The inhibition of the Gárdos effect is caused neither by the inhibition of the anion channel by PXB nor by the inhibition of Ca 2+ entry. It can be ascribed to the inhibition of the Ca 2+ ‐activated K + channel. The mechanism of the inhibition remains to be elucidated.