1. Beleslin, D., Polak, R. L.: Depression by morphine and chloralose of acetylcholine release from cat's brain. J. Physiol. (Lond.) 177, 411?419 (1965).
2. Bernheim, F., Bernheim, M. L. C.: Action of drugs on the cholinesterase of the brain. J. Pharmacol. exp. Ther. 57, 427?436 (1936).
3. Bianchi, C., Franceschini, J.: Experimental observations on Haffner's method for testing analgesic drugs. Brit. J. Pharmacol. 9, 280?284 (1954).
4. Cox, B. M., Weinstock, M.: The effect of analgesic drugs on the release of acetylcholine from electrically stimulated guinea pig ileum. Brit. J. Pharmacol. 27, 81?92 (1966).
5. Dole, V. P.: Biochemistry of addiction. Ann. Rev. Biochem. 39, 821?838 (1970).