Emamectin B1a

Emamectin B1a (L-656,748) is a semisynthetic derivative of avermectin B1a that binds to GABA receptors (Ki=17.6 nM in rat brain membranes) and enhances GABA responses. Emamectin B1a acitivates GABAA receptors α1β1γ2, α1β2γ2, and α1β3γ2 with IC50s of 57, 210, and 49.8 nM, respectively. Emamectin B1a also binds to glycine receptors, inhibiting glycine receptors with an IC50=218 nM in rat spinal cord. Emamectin B1a (1.067 ng/mL) caused 90% mortality of S. exigua larvae in foliar spray bioassays and topical application, making it more toxic than avermectin B1.

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[1]Dawson, et al. Anticonvulsant and adverse effects of avermectin analogs in mice are mediated through the g-aminobutyric acidA receptor. J. Pharmacol. Exp. Ther. 295(3), 1051-1060 (2000).