Fig. 4.

Copper concentration in synaptosomes correlates with PrP^C expression. The copper concentration in whole-brain homogenates (A) and synaptosomal fractions (B) of wild-type (WT), Prnp^0/0, and Prnp-reconstituted Prnp^0/0 mice (tg20) was studied by atomic absorption spectroscopy. The copper concentration was not significantly different in the whole-brain homogenates of the three lines tested. The synaptosomal preparations reveal a significantly reduced copper concentration in Prnp^0/0 mice compared with wild-type mice (Student’s t test;p < 0.05). In PrP^Cgene-reconstituted Prnp^0/0 mice (tg20), the synaptosomal copper concentration was similar to wild-type mice. Shown are the mean and SE for four to six independent preparations of five age- and sex-matched brains. Asterisks indicate that the observed differences were found to be statistically significant.