THE BINDING OF [3H]‐PROPYLBENZILYLCHOLINE MUSTARD BY LONGITUDINAL MUSCLE STRIPS FROM GUINEA‐PIG SMALL INTESTINE

Abstract

1 The synthesis of tritium labelled propylbenzilylcholine mustard ([³H]-PrBCM; N-2′-chloroethyl-N-[2″, 3″-³H₂] propyl-2-aminoethyl benzilate) is described. 2 The uptake by muscle strips was measured and shown to be considerably increased by previous immersion of the muscle in distilled water. 3 A considerable part of the uptake is inhibited selectively by atropine, but not by nicotinic antagonists. A number of muscarinic agonists also inhibit uptake and their apparent affinity constants have been determined. 4 The uptake by atropine-sensitive sites is temperature-insensitive, whereas the other sites are temperature-sensitive. Recovery is highly temperature-sensitive and there is good agreement between recovery of sensitivity to agonists and loss of radioactivity from the muscle.