Spider Toxin Card | ArachnoServer

Toxin Name	κ-theraphotoxin-Gr2c
Source Species	*Grammostola rosea* (Chilean rose tarantula)
Toxin Group	Theraphotoxin
Description	An unusual toxin that has been described in two separate patents for different applications. The first patent (U.S. Pat No. US5877026) describes the analgesic properties of κ-TRTX-Gr2c. When injected intrathecally into young rats, κ-TRTX-Gr2c showed analgesic effects in pain models such as the tail flick latency test, hot plate threshold test, von Frey threshold test, and formalin pain test. The second patent (U.S. Patent No. 5968838) describes the ability of the toxin to block mechanosensitive ion channels (also called stretch-activated channels or SACs). The toxin blocks hypotonic cell swelling induced calcium release without blocking calcium channels, and has antiarrhthymic activity. Finally, to further complicate the pharmacology of this toxin, it is a clearly a paralog of κ-theraphotoxin-Gr2b (the toxins differ by only two amino acid residues at the C-terminus), which inhibits the KvAP voltage-gated potassium channel from the archaebacterium Aeropyrum pernix by binding to the voltage sensor paddle. The diverse pharmacology of the toxin probably derives from an ability to partition into the lipid membrane.
Discovered	1999