Block of synaptic transmission in insect CNS by toxins from the venom of the wasp Megascolia flavifrons (Fab.).
1. The effects of the venom and its fractions of Megascolia flavifrons have been studied on synaptic transmission and axonal excitability of the giant interneuron of the cockroach. 2. The venom does not affect axonal excitability, but blocks synaptic transmission, and induces postsynaptic depolarization with a delay. 3. Five different active fractions have been recognized. 4. Three fractions of them contain substances already identified as histamine, Thr6 bradykinin and Thr6 bradykinin-Lys-Ala (megascoliakinin). 5. Three fractions contain activities, which have not yet been chemically identified. 6. All of them, and also bradykinin block synaptic transmission; histamine was not active.
D000818:Animals; D001514:Bee Venoms / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D005724:Ganglia / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D010526:Periplaneta; D009435:Synaptic Transmission / Q000187:drug effects*; D014862:Wasp Venoms / Q000494:pharmacology*; D014863:Wasps
D001514:Bee Venoms; D014862:Wasp Venoms