Modulation of nicotinic acetylcholine and N-methyl- d-aspartate receptors by some Hymenopteran venoms

Abstract

The effect of 19 venoms from solitary wasps, solitary bees, social wasps and ants were investigated for their effects on nicotinic acetylcholine receptors (nAChR) and ionotropic glutamate receptors (IGRs) of both the N-methyl- d-aspartate (NMDAR) and non-NMDAR type. Whole-cell patch clamp of human muscle TE671 cells was used to study nAChR, and of rat cortical and cerebellar granule cells for IGRs. Solitary wasp venoms caused significant voltage-dependent antagonism of nAChR responses to 10 μM ACh and NMDAR responses to 100 μM NMDA (+10 μM glycine) when co-applied at 1 μg/ml with the agonists. At positive holding potentials ( V H) potentiation of these receptors was observed with some venoms. Solitary bee venoms only affected nAChR by causing either voltage-independent antagonism or potentiation of their responses to 10 μM ACh. Of four social wasp venoms, one acted on nAChR by potentiating responses to 10 ACh, while another generated an ACh-like response when applied alone. They had no effect on IGRs. Of the two ant venoms, one caused voltage-independent inhibition of nAChR. Neither affected IGRs. The data indicate the presence of nAChR agonists and antagonists and NMDAR antagonists in Hymenopteran venoms and warrant further investigation to separate and identify these venom components.