PT  - JOURNAL ARTICLE
AU  - MICHAEL H. SHEAUD
AU  - GEORGE K. AGHAJANIAN
TI  - STIMULATION OF THE MIDBRAIN RAPHE: EFFECT ON SEROTONIN METABOLISM
DP  - 1968 Oct 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 425--430
VI  - 163
IP  - 2
4099  - http://jpet.aspetjournals.org/content/163/2/425.short
4100  - http://jpet.aspetjournals.org/content/163/2/425.full
SO  - J Pharmacol Exp Ther1968 Oct 01; 163
AB  - The midbrain of rats was stimulated electrically in the region of the dorsal and mediati raphe via acutely placed electrodes, and parameters of stimulation were varied. In all animals, concentrations of serotonin and 5-hydroxyindoleacetic acid were measured in the forebrain, and sites of electrode placement in the brainstem were determined histologically. Results indicated a close correlation between electrode placement and changes in indole levels in the forebrain. Only in those regions of the midbrain with serotonin-containing itetirons did stimulation produce an increase in serotonin catabolism. There was a maximum change at a stimulus frequency of 10 pulses/sec. This amounted to a fall in serotonin of 18% and a rise in 5-hy- droxyindoleacetic acid of 80% with 1 hr of stimulation. The fall in serotonin reaches a maximum in the first 15 min. Thereafter, the concentration of serotonin does not change, while 5-hydroxyindoleacetic acid continues to rise. The fact that the serotonin concentration remains constant beyond 15 min, despite continued stimulation, suggests that there has been an upward adjustment in the rate of serotonin biosynthesis. © 1968 by the Williams & Wilkins Co.