Rho-conotoxin TIA

Rho-conotoxin TIA has been isolated from the venom of the fish-hunting marine cone snail Conus tulipa. Rho-conotoxin TIA is a selective antagonist of α1-adrenoreceptor (α1A-, α1B- and α1D-AR). It acts non-competitively onto α1B-adrenoreceptor but competitively on α1A-adrenoreceptor and α1D-adrenoreceptor. The most important residue for activity is Arg4. Rho-conotoxin TIA is 10-fold selective for human α1B-adrenoreceptor over α1A-adrenoreceptor and α1D-adrenoreceptor. The IC50 values for Rho-conotoxin TIA for inhibition of 125I-BE were 18 nM for human α1A-AR, 2 nM for α1B-AR and 25 nM for α1D-AR.