Early life events have been thought to contribute towards vulnerability to
drug addiction later in life. In the present investigation, the effect of d
aily neonatal maternal isolation stress on NMDA channel activity was studie
d. [H-3]MK-801 binding was measured in several brain regions from neonatall
y isolated (ISO) and nonhandled (NH) adult male and female rats. Maximal [H
-3]MK-801 binding in the caudate-putamen of male ISO rats was 58% higher co
mpared to same sex NH rats. Unlike male rats, maximal [H-3]MK-801 binding i
n the caudate-putamen of female ISO rats was lower than female NH rats. No
other brain region showed any significant difference in maximal [H-3]MK-801
binding between ISO and NH male and female rats, respectively. There was n
o effect of pup isolation on the binding affinity (K-d value) in either sex
. Repeated maternal isolation is associated with alterations in the NMDA ch
annel activity in the caudate-putamen of adult rats, and may be responsible
for the augmentation in the addictive behavior reported. (C) 2001 Elsevier
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