sentences:  Subsequently, Macallan and his co-workers showed that MLA also competed with 125I-α-bungarotoxin (Ki ~1 x 10−9M) and tritiated (−)-[[nicotine]] (Ki ~4 x 10−6M) in a receptor preparation from rat brain.These workers also reported that MLA displaced125I-α-bungarotoxin from purified "Torpedo" ([[electric ray]]) [[nicotinic acetylcholine receptors]] (nAChRs) with a Ki ~1 x 10−6M.Similar experiments performed later by Ward et al.