PT  - JOURNAL ARTICLE
AU  - H. B. MYERS
TI  - CROSS TOLERANCE ALTERED SUSCEPTIBILITY TO CODEIN, HEROIN, CANNABIS-INDICA AND CHLORAL-HYDRATE IN DOGS HAVING AN ACQUIRED TOLERANCE FOR MORPHINE
DP  - 1916 Aug 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 417--437
VI  - 8
IP  - 8
4099  - http://jpet.aspetjournals.org/content/8/8/417.short
4100  - http://jpet.aspetjournals.org/content/8/8/417.full
SO  - J Pharmacol Exp Ther1916 Aug 01; 8
AB  - 1. A marked crossed tolerance exists to codein and to heroin in dogs habituated to morphine, in so far as effects upon the respiratory center are concerned. 2. A slight crossed tolerance exists between codein and morphine, and between heroin and morphine in regard to their actions upon the tissues governing equilibrium. 3. Dogs tolerant to morphine when given codein or heroin have increased intestinal peristalsis. 4. No evidence of crossed toleration to cannabis indica or to chioral hydrate exists in dogs tolerant to large amounts of morphine. 5. The experiments cited show that a cross tolerance may exist between closely related drugs but that this tolerance is evidenced only on those functions in which the drugs have a common selective action.