Noradrenaline triggers viper's venom

摘要

Most vipers don't waste their venom on any old mouthful. It takes time and energy to produce a gland-full of venom, so profligacy isn't an option. But just what triggers toxin synthesis wasn't elear until Norma Yamanouye and her colleagues began testing the response of Bothrops jararaca's, venom glands to noradrenaline. The venom gland's adrenoccptor hecame desensitised to noradrenaline after venom was extracted from the snake, but after a month the receptor had regained its sensitivity. So once venom production was triggered, it didn't seem possible to stimulate the adrenoccptor again until the gland was recharged with venom 30 days later (p. 411).