Hw. Broening et al., AGE MODULATES THE LONG-TERM BUT NOT THE ACUTE EFFECTS OF THE SEROTONERGIC NEUROTOXICANT 3,4-METHYLENEDIOXYMETHAMPHETAMINE, The Journal of pharmacology and experimental therapeutics, 271(1), 1994, pp. 285-293
Tissue levels of serotonin (5-HT), levels of its metabolite 5-hydroxyi
ndoleacetic acid (5-HIAA) and populations of 5-HT reuptake sites were
measured in the brains of rats exposed to 3,4-methylenedioxymethamphet
amine (MDMA) at selected developmental ages. MDMA exposure at postnata
l day (PND) 10 did not result in altered 5-HT or 5-HIAA levels 1 week
after administration in any brain region examined. However, MDMA expos
ure at PND 40 and PND 70 resulted in dose-dependent reductions in 5-HT
and 5-HIAA levels at 1 week in all brain regions examined. Time cours
e studies revealed that at PND 10, MDMA acutely (less than or equal to
24 hr) reduced 5-HT levels and that these levels later recovered to c
ontrol levels. MDMA also acutely reduced 5-HT levels at PND 40 and PND
70, but at these ages the 5-HT levels were persistently depressed (gr
eater than or equal to 72 hr). Time course studies also revealed that
MDMA acutely elevated dopamine levels in caudate putamen at PND 40 and
PND 70, but no alterations in dopamine levels were observed at PND 10
. Analysis of 5-HT reuptake site populations revealed that at PND 10 a
nd PND 40, MDMA had little effect on reuptake site populations. At PND
70, however, MDMA reduced 5-HT reuptake site populations as early as
24 hr after administration. These experiments demonstrate not only tha
t the biochemical effects of MDMA exposure are altered by the developm
ental status of the experimental animal, but also that each individual
biochemical component may show differing sensitivities to alteration
by MDMA at different developmental ages.