TY - JOUR
T1 - The amine-depleting effects of 5,7-dihydroxytryptamine (5,7-DHT) in C57BL/6 mice do not increase with age
AU - Finnegan, Kevin T.
AU - DeLanney, Louis E.
AU - Irwin, Ian
AU - Ricaurte, George A.
AU - William Langston, J.
N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1989/9/4
Y1 - 1989/9/4
N2 - A recent approach to identifying the factors that predispose neurons to an early death in Parkinson's or Alzheimer's disease has been study how the effects of specific neurotoxins are altered by increasing maturity. We determined the dose-related serotonin and norepinephrine-depleting effects of the selective neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), in C57BL/6 mice of 2 different ages. Norepinephrine and serotonin in the hippocampus were assayed 1 week after the intracerebroventricular (i.c.v.) administration of 5,7-DHT. 5,7-DHT produced equivalent, dose-related depletion of hippocampal norepinephrine in both age groups. Since the effects of 5,7-DHT on noradrenergic neurons may, at leastin part, depend on the monoamine oxidase (MAO)-generated formation of hydrogen peroxide and associated oxy-radicals,this result suggests that noradrenergic neurons do not become more vulnerable to oxidative stress with aging. We also found that the noradrenergic-depleting effects of 5,7-DHT were blocked by the non-selective MAO inhibitor pargyline (50mg/kg, i.p.), whilethe selective MAO B inhibitor deprenyl (10 mg/kg, i.p.) failed to prevent this depletion. These latter results suggest that it is the A form of MAO that plays an important role in the mechanism of 5,7-DHT-induced noradrenergic toxicy. Somewhat unexpectedly, older mice were found to be less susceptible to the serotonin-depleting effects of 5,7-DHT. Although the mechanism by whichthis compound damages serotonergic neurons is uncertain, our results show that the increased susceptibility of serotonergic neurons to 5,7-DHT in young animals extends well beyond the neonatal period.
AB - A recent approach to identifying the factors that predispose neurons to an early death in Parkinson's or Alzheimer's disease has been study how the effects of specific neurotoxins are altered by increasing maturity. We determined the dose-related serotonin and norepinephrine-depleting effects of the selective neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), in C57BL/6 mice of 2 different ages. Norepinephrine and serotonin in the hippocampus were assayed 1 week after the intracerebroventricular (i.c.v.) administration of 5,7-DHT. 5,7-DHT produced equivalent, dose-related depletion of hippocampal norepinephrine in both age groups. Since the effects of 5,7-DHT on noradrenergic neurons may, at leastin part, depend on the monoamine oxidase (MAO)-generated formation of hydrogen peroxide and associated oxy-radicals,this result suggests that noradrenergic neurons do not become more vulnerable to oxidative stress with aging. We also found that the noradrenergic-depleting effects of 5,7-DHT were blocked by the non-selective MAO inhibitor pargyline (50mg/kg, i.p.), whilethe selective MAO B inhibitor deprenyl (10 mg/kg, i.p.) failed to prevent this depletion. These latter results suggest that it is the A form of MAO that plays an important role in the mechanism of 5,7-DHT-induced noradrenergic toxicy. Somewhat unexpectedly, older mice were found to be less susceptible to the serotonin-depleting effects of 5,7-DHT. Although the mechanism by whichthis compound damages serotonergic neurons is uncertain, our results show that the increased susceptibility of serotonergic neurons to 5,7-DHT in young animals extends well beyond the neonatal period.
KW - 5,7-Dihydroxytryptamine
KW - Aging
KW - Monoamine oxidase
KW - Neurotoxin
KW - Norepinephrine
KW - Parkinson's disease
KW - Serotonin
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U2 - 10.1016/0006-8993(89)91072-X
DO - 10.1016/0006-8993(89)91072-X
M3 - Article
C2 - 2804634
AN - SCOPUS:0024324567
SN - 0006-8993
VL - 496
SP - 251
EP - 256
JO - Brain research
JF - Brain research
IS - 1-2
ER -