1. Bartlet, A. L.: The 5-hydroxytryptamine content of mouse brain and whole mice after treatment with some drugs affecting the central nervous system. Brit. J. Pharmacol. 15, 140?146 (1960).
2. Cochin, J., Axelrod, J.: Biochemical and pharmacological changes in the rat following chronic administration of morphine, nalorphine and normorphine. J. Pharmacol. exp. Ther. 125, 105?110 (1959).
3. Collier, H. O. J.: A general theory of the genesis of drug dependence by induction of receptors. Nature (Lond.) 205, 181?182 (1965).
4. Contreras, E., Tamayo, L.: Effects of drugs acting in relation to sympathetic functions on the analgesic action of morphine. Arch. int. Pharmacodyn. 160, 312?320 (1966).
5. Gaddum, J. H., Picarelli, Z. P.: Two kinds of tryptamine receptors. Brit. J. Pharmacol. 12, 323?328 (1957).