title: The pharmacology of Microbracon venom.
abstract: 1. Wasps of the genus Microbracon generally paralyse larvae of Lepidoptera. The wasp larva is exophagous on the paralysed host. The venom acts slowly and causes a flaccid paralysis. The venom of M. hebetor is extremely active in Lepidoptera, less active in honeybee workers, much less active in locusts and mealworms and probably inactive in non-insects. 2. In Lepidoptera and in locusts the venom presynaptically blocks the excitatory, but not the inhibitory, neuromuscular transmission. M. hebetor venom contains two high mol. wt toxins. A-MTX and B-MTX, with essentially the same action on neuromuscular transmission as the crude venom. Differences in dose-response curves of the two toxins, as well as differences in sensitivity to the two toxins between insect species are described. In wax moth larvae both A-MTX and B-MTX cause a slow and transient paralysis with a maximal effect after about 20 hr. The rate of recovery is dose-dependently decreased by the toxins.
mesh_terms: D000818:Animals; D001514:Bee Venoms / Q000633:toxicity*; D007313:Insecta / Q000187:drug effects*; D007814:Larva / Q000187:drug effects; D007915:Lepidoptera / Q000187:drug effects; D009469:Neuromuscular Junction / Q000502:physiology; D010243:Paralysis / Q000139:chemically induced; D013045:Species Specificity; D009435:Synaptic Transmission / Q000187:drug effects*; D014862:Wasp Venoms / Q000633:toxicity*
chemical_list: D001514:Bee Venoms; D014862:Wasp Venoms