title: Triphasic locomotor response of a plant-parasitic nematode to avermectin: inhibition by the GABA antagonists bicuculline and picrotoxin.
abstract: The response of the plant parasitic nematode, Meloidogyne incognita (J2 stage) to avermectin B2a-23-one is triphasic, comprising an initial loss of locomotor activity where the juveniles remain sensitive to touch, a recovery phase and a final loss of activity where the juveniles are relatively insensitive to touch. In contrast, the acetylcholinesterase inhibitor, oxamyl, causes initial hyperactivity of juveniles followed by a progressive decline in movement. The addition of bicuculline and to a lesser extent picrotoxin, both antagonists of gamma-aminobutyric acid (GABA), blocks the action of avermectin on M. incognita.
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000037:antagonists & inhibitors*; D001640:Bicuculline / Q000494:pharmacology*; D007559:Ivermectin / Q000031:analogs & derivatives*; D007783:Lactones / Q000037:antagonists & inhibitors*; D009043:Motor Activity / Q000187:drug effects; D009348:Nematoda / Q000187:drug effects*; D010852:Picrotoxin / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000187:drug effects; D011963:Receptors, GABA-A; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D000871:Anthelmintics; D001640:Bicuculline; D007559:Ivermectin; D007783:Lactones; D010852:Picrotoxin; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; C019264:avermectin