Tetanus and Botulinum Toxins Inhibit, and Black Widow Spider Venom Stimulates the Release of Methionine‐Enkephalin‐Like Material In Vitro

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Abstract
The actions of tetanus toxin, botulinum A toxin and black widow spider venom on the release of Met-enkephalin-like immunoreactivity were studied on a particulate fraction prepared from rat striata. Depending on the duration of preincubation, tetanus toxin diminished the release evoked by veratridine (50 .mu.M final concentration), and abolished it at final concentrations of 0.1-1 .mu.g/ml. Botulinum A toxin was .apprx. 10- to 20-fold less potent. Heating or pretreatment with antitoxin inactivated the clostridial toxins. The particulate fraction pretreated with Vibrio cholerae neuraminidase retained its toxin sensitivity. Tetanus toxin also depressed the release due to sea anemone toxin 2 and high K+. Spider venom stimulated the release in a concentration-dependent manner and required the presence of Ca2+; its effects were depressed by tetanus toxin. Both clostridial toxins and spider venom acted as broad-range presynaptic neurotoxins on peptidergic transmitter systems.