Blast Can'T Find Databases

I've installed BLAST locally, I've downloaded the nr database via update update_blastdb, I've added .ncbirc to the home folder which has

[BLAST]
BLASTDB=/home/bioinformatics/Desktop/blastDB

and yet when I try to run blastn I get this:

blastn -query Desktop/sea_urchin_output1/permutations.fa -db nr
BLAST Database error: No alias or index file found for nucleotide database [nr] in search path [/home/bioinformatics::/home/bioinformatics/Desktop/blastDB:]

I've tried following instructions to get this to run, but it still doesn't work. Is there something I'm missing?