Neurotoxin that blocks the small-conductance calcium-activated potassium (SK) channels KCa2.1/KCNN1/SK1, KCa2.2/KCNN2/SK2 and KCa2.3/KCNN3/SK3 (PubMed:6122211, PubMed:9459560, PubMed:9287325, PubMed:10696100, PubMed:11533126, PubMed:11212219, PubMed:17142458, PubMed:20562108, PubMed:32560481). Also irreversibly blocks the voltage-gated potassium channel Kv1.3/KCNA3 (IC(50)=13 nM) (PubMed:28108814). Potently blocks human, rat and mouse KCa2.2/KCNN2/SK2 channels (IC(50)=27-140 pM), and moderately blocks human and rat KCa2.3/KCNN3/SK3 channels (IC(50)=0.6-4 nM), and human (IC(50)=0.7-12 nM) and mouse (IC(50)=28 nM) KCa2.1/KCNN1/SK1 channels (PubMed:9459560, PubMed:9287325, PubMed:10696100, PubMed:11533126, PubMed:11212219, PubMed:17142458, PubMed:20562108). However, other reports found that it did not block the human KCa2.1/KCNN1/SK1 channels (PubMed:9287325). Also able to inhibit neuromuscular transmission by a mechanism independent of the blockade of SK channels, which may involve the activation of inhibitory muscarinic M2 receptors on motor nerve terminals (PubMed:19818752). Expressed by the venom gland. LD(50) is 3-5 mg/ kg by intravenous injection into mice. When administered at high doses, exerts anti-inflammatory, anti-oxidative, anti-fibrotic and anti-apoptotic properties in several models of inflammatory disease, including gouty arthritis, atherosclerosis, atopic dermatitis and acute kidney injury (PubMed:28958612, PubMed:32560481, PubMed:33287398, PubMed:32289477). Down-regulates pro-inflammatory signaling pathways, such as the NF-kappaB and STAT3 pathways, probably by blocking SK channels such as KCa2.2/KCNN2/SK2 and/or KCa2.3/KCNN3/SK3 which are thought to be involved in promoting some inflammatory responses (PubMed:28958612, PubMed:32560481, PubMed:33287398, PubMed:32289477). For example in mouse and rat microglia cells, inhibits LPS-activated KCa2.2/KCNN2/SK2 channels and TLR4 expression leading to the down-regulation of the NF-kappaB, STAT, and MAPK/ERK signaling pathways and, as a consequence, decreases secretion of pro-inflammatory cytokines (PubMed:32560481). In rats, a dose of 1 ng results in neurodegeneration specifically in the Purkinje cells of the cerebellum, and induces seizures characterized by hypersensitivity to noise, loss of postural control, paroxystic jerking, and alternating periods of great agitation with tonic-clonic convulsions and periods of total prostration.