Hi,
I was isolating synaptosomes from rat brain and I wasn't able to see 18s or 28s of the rRNA, but we were able to see a small peak of 5s . When I measure the RNA on nano drop I get good amount of RNA per ul (~60-100 ng/ul).
We pipet up and down gently to break down the synaptosomes after adding Trizole. Then we use the standard RNA extraction protocol.