# Iberiotoxin
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> Source: https://en.wikipedia.org/wiki/Iberiotoxin
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!The amino acid sequence of Iberiotoxin[{{cite journal | last1 = Ferrat | first1 = G | last2 = Bernard | first2 = C | last3 = Fremont | first3 = V | last4 = Mullmann | first4 = TJ | last5 = Giangiacomo | first5 = KM | last6 = Darbon | first6 = H | title = Structural basis for alpha-K toxin specificity for K+ channels revealed through the solution 1H NMR structures of two noxiustoxin-iberiotoxin chimeras | journal = Biochemistry | volume = 40 | issue = 37 | pages = 10998–1006 | year = 2001 | pmid = 11551195 | doi=10.1021/bi010228e}}] It is also known as "Potassium channel toxin alpha-KTx 1.3" or IbTx. The complete [amino acid](/source/amino_acid) sequence has been defined and it displays 68% [sequence homology](/source/sequence_homology) with [charybdotoxin](/source/charybdotoxin).[{{cite journal | last1 = Galvez | first1 = A | last2 = Gimenez-Gallego | first2 = G | last3 = Reuben | first3 = JP | last4 = Roy-Contancin | first4 = L | last5 = Feigenbaum | first5 = P | last6 = Kaczorowski | first6 = GJ | last7 = Garcia | first7 = ML | title = Purification and characterization of a unique, potent, peptidyl probe for the high conductance calcium-activated potassium channel from venom of the scorpion Hottentotta tamulus | journal = The Journal of Biological Chemistry | volume = 265 | issue = 19 | pages = 11083–90 | year = 1990 | doi = 10.1016/S0021-9258(19)38560-6 | pmid = 1694175 | doi-access = free | hdl = 10261/177752 | hdl-access = free }}]
== Target and mode of action ==
Iberiotoxin binds to the outer face of the large-conductance calcium-activated potassium channels (maxiK or [BK channel](/source/BK_channel)s) with high affinity (Kd ~1 nM).[{{cite journal | last1 = Candia | first1 = S | last2 = Garcia | first2 = ML | last3 = Latorre | first3 = R | title = Mode of action of iberiotoxin, a potent blocker of the large conductance Ca(2+)-activated K+ channel | journal = Biophysical Journal | volume = 63 | issue = 2 | pages = 583–90 | year = 1992 | pmid = 1384740 | pmc = 1262182 | doi = 10.1016/S0006-3495(92)81630-2 | bibcode=1992BpJ....63..583C}}] It selectively inhibits the current by decreasing both the probability of opening and the open time of the channel.[{{cite journal | last1 = Bawaskar | first1 = HS | last2 = Bawaskar | first2 = PH | title = Management of the cardiovascular manifestations of poisoning by the Indian red scorpion (Hottentotta tamulus) | journal = British Heart Journal | volume = 68 | issue = 5 | pages = 478–80 | year = 1992 | pmid = 1467032 | pmc = 1025191 | doi=10.1136/hrt.68.11.478}}]
== Treatment ==
Treatment is mainly symptomatic. Local [pain](/source/pain) is treated by injecting [dehydroemetine](/source/dehydroemetine) at the site of the sting. [Hypovolaemia](/source/Hypovolaemia) is corrected by oral rehydration solution. Agitated, confused and non-cooperative patients are given a 5% [dextrose](/source/dextrose) [saline](/source/saline_(medicine)) drip. Patients with [hypertension](/source/hypertension) on admission are given a single dose of 5 mg [sublingual](/source/sublingual) [nifedipine](/source/nifedipine) and oral [prazosin](/source/prazosin). The blood pressure in patients with hypertension is controlled with sublingual nifedipine alone. Patients with pulmonary [oedema](/source/oedema) are propped up and given intravenous [aminophylline](/source/aminophylline), [intravenous sodium bicarbonate](/source/intravenous_sodium_bicarbonate), oral [prazosin](/source/prazosin), and [oxygen](/source/oxygen) by mask.