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

Drinyaev, V.A.; Mosin, V.A.; Kruglyak, E.B.; Sterlina, T.S.; Kataev, A.A.; Berestovsky, G.N.; Kokoz, Y.M.

Journal of Membrane Biology 182(1): 71-79

2001


ISSN/ISBN: 0022-2631
PMID: 11426301
DOI: 10.1007/s00232-001-0032-2
Accession: 003725011

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Abstract
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.

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