Linked Life Data

12527813

Source:http://linkedlifedata.com/resource/pubmed/id/12527813

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2003-1-15
pubmed:abstractText
Maurotoxin, a 34-amino acid toxin from Scorpio maurus scorpion venom, was examined for its ability to inhibit cloned human SK (SK1, SK2, and SK3), IK1, and Slo1 calcium-activated potassium (K(Ca)) channels. Maurotoxin was found to produce a potent inhibition of Ca(2+)-activated (86)Rb efflux (IC(50), 1.4 nM) and inwardly rectifying potassium currents (IC(50), 1 nM) in CHO cells stably expressing IK1. In contrast, maurotoxin produced no inhibition of SK1, SK2, and SK3 small-conductance or Slo1 large-conductance K(Ca) channels at up to 1 microM in physiologically relevant ionic strength buffers. Maurotoxin did inhibit (86)Rb efflux (IC(50), 45 nM) through, and (125)I-apamin binding (K(i), 10 nM) to SK channels in low ionic strength buffers (i.e., 18 mM sodium, 250 mM sucrose), which is consistent with previous reports of inhibition of apamin binding to brain synaptosomes. Under similar low ionic strength conditions, the potency for maurotoxin inhibition of IK1 increased by approximately 100-fold (IC(50), 14 pM). In agreement with its ability to inhibit recombinant IK1 potassium channels, maurotoxin was found to potently inhibit the Gardos channel in human red blood cells and to inhibit the K(Ca) in activated human T lymphocytes without affecting the voltage-gated potassium current encoded by Kv1.3. Maurotoxin also did not inhibit Kv1.1 potassium channels but potently blocked Kv1.2 (IC(50), 0.1 nM). Mutation analysis indicates that similar amino acid residues contribute to the blocking activity of both IK1 and Kv1.2. The results from this study show that maurotoxin is a potent inhibitor of the IK1 subclass of K(Ca) potassium channels and may serve as a useful tool for further defining the physiological role of this channel subtype.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0026-895X
pubmed:author
pubmed:issnType
Print
pubmed:volume
63
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
409-18
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Maurotoxin: a potent inhibitor of intermediate conductance Ca2+-activated potassium channels.
pubmed:affiliation
Icagen Inc., Durham, North Carolina 27703, USA. ncastle@icagen.com
pubmed:publicationType
Journal Article