Effect of avermectins on Ca2+-dependent Cl- currents in plasmalemma of Chara corallina cells

• Published in: The Journal of membrane biology Vol. 182; no. 1; pp. 71 - 79
• Main Authors: Drinyaev, V A, Mosin, V A, Kruglyak, E B, Sterlina, T S, Kataev, A A, Berestovsky, G N, Kokoz, Y M
• Format: Journal Article
• Language: English
• Published: United States 01.07.2001
• Subjects: Calcium - metabolism; Cell Membrane - physiology; Chloride Channels - drug effects; Chloride Channels - metabolism; Chlorides - metabolism; Chlorides - physiology; Dose-Response Relationship, Drug; Electrophysiology; Eukaryota; Ivermectin - analogs & derivatives; Ivermectin - pharmacology; Patch-Clamp Techniques
• ISSN: 0022-2631
• DOI: 10.1007/s00232-001-0032-2

A natural complex of avermectins, aversectin C, and a component of this complex, avermectin A1, were shown to change the conductivity of Ca2+-dependent Cl- channels of plasmalemma of Chara corallina cells by acting from the outer side of the cellular membrane. Low concentrations of aversectin C and avermectin A1 increased the Cl- current: K1/2 = 35 ng/ml for the whole complex and K1/2 = 21 pg/ml for A1. Relatively high concentrations of the compounds suppressed the Cl- current: K1/2 = 2.2 microg/ml for aversectin C and K1/2 = 4.2 ng/ml for A1. The Hill coefficient for the interaction of avermectin A1 with the corresponding targets was identical for stimulation and suppression of the Cl- current: 2.8 and 2.5, respectively. Bicuculline, a nonspecific inhibitor of the GABAa receptors, did not influence stimulation of Cl- currents caused by low concentrations of avermectins, but at the same time blocked suppression of the Cl- currents by high concentrations of avermectins. Avermectins A2, B1, B2, abamectin and 22,23-dihydroavermectin B1 (ivermectin) did not affect the Cl- currents of Chara corallina cells.