RESISTANCE OF THE EGYPTIAN MONGOOSE TO SARAFOTOXINS

The Egyptian mongoose (Herpestes ichneumon) is known for its resistanc e to viperid and elapid venoms. The current work demonstrates that it is also resistant to the venom of Atractaspis and its most toxic compo nent, sarafotoxin-b, Intravenous administration of this toxin, at a do se of about 13 times LD100 for mice, resulted in disturbance in electr ocardiograms in the mongoose, which returned to normal after several h ours. Sarafotoxin-b failed to induce contraction of mongoose aortal pr eparations. Endothelin-1, which was demonstrated in tissue extracts of the mongoose by immunological methods, induced contraction of the iso lated mongoose aorta. This contraction, however, was greatly reduced w hen endothelin-1 was applied on top of sarafotoxin-b. Binding studies revealed endothelin/sarafotoxin-specific binding sites in brain and ca rdiovascular preparations of the mongoose. It is suggested that some s tructural features of endothelin/sarafotoxin receptors in the mongoose enable them to differentiate between the two peptides. (C) 1997 Elsev ier Science Ltd.