Jump to: Page Content, Section Navigation, Site Navigation, Site Search, Account Information, or Site Tools.
|
|
Articles
Narcotic Drugs: Effects on the Serotonin Biosynthetic Systems of the Brain
1 Department of Psychiatry, University of California at San Diego, La Jolla 92037
The effects of short- and long-term administration of morphine on the activity of two measurable forms of rat brain tryptophan hydroxylase were studied. Morphine administration produced an immediate decrease and a longterm increase in the nerve ending (particulate) enzyme activity but did not change the cell body (soluble) enzyme activity. Cocaine administration demnonstrated a short-term decrcease in measurable nerve eniding enzyme activity that was due to the inhibition of the high affinity uptake (the Michaelis constant, Km is 10-5 molar) of trytophan, the serotonin precursor. Cocaine did not aflect the low affinity uptake Km = 10-5 molar) of tryptophan. Both the uptake of the precursor and the enizymiie activity appeared to be drug-sensitive regullatory processes in the biosynthlesis of serotonin.
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
|
Science. ISSN 0036-8075 (print), 1095-9203 (online)