Toxins 'R' Us: more pharmacological tools from nature's superstore

Conus venoms from marine cone snails continue to provide novel bioactive components. Two new classes of conopeptide specifically block alpha(1)-adrenoceptors (rho-conopeptide) and noradrenaline transporters (chi-conopeptides). Both classes are small peptides with two disulfide bonds. Rho-conopeptide is structurally similar to alpha-conotoxins, which block nicotinic acetylcholine receptors, whereas the chi-conopeptides are unrelated to other conotoxins. Both types of conopeptides are non-competitive blockers. Because these peptides demonstrate greater selectivity than current drugs in clinical use, they could lead to the development of improved therapeutics.