PT  - JOURNAL ARTICLE
AU  - SUEN, FU-HSIUNG
AU  - LOH, HORACE H.
AU  - WAY, E. LEONG
TI  - BRAIN SEROTONIN TURNOVER IN MORPHINE TOLERANT AND DEPENDENT MICE
DP  - 1970 Nov 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 427--434
VI  - 175
IP  - 2
4099  - http://jpet.aspetjournals.org/content/175/2/427.short
4100  - http://jpet.aspetjournals.org/content/175/2/427.full
SO  - J Pharmacol Exp Ther1970 Nov 01; 175
AB  - The rate of serotonin (5-HT) synthesis in the brains of mice rendered tolerant to and physically dependent on morphine either by s.c. implantation of a morphine pellet for three to four days or by daily s.c. injections of increasing doses of morphine was found to be about twice that of control animals receiving a placebo implant or daily saline injections. Inhibition of brain 5-HT synthesis by p-chlorophenylalanine was accompanied by a decrease in tolerance and dependence development to morphine. The concomitant administration of naloxone to reduce tolerance and physical dependence development to daily injections of morphine resulted also in a decrease in the rate of brain 5-HT synthesis. Although the roles of other biogenic amines have not been excluded, the results suggest that increased brain 5-HT synthesis may be associated with tolerance and physical dependence development to morphine in the mouse but do not establish a causal relationship. © 1970 by The Williams & Wilkins Co.