Postnatal stress selectively upregulates striatal N-methyl-D-aspartate receptors in male rats

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 Science B.V. All rights reserved.