FIGURE 1.

Effect of buffer conditions on the integrity of ribosomal RNA (rRNA). (A) Electropherogram showing rRNA integrity for fresh-frozen tissue (black line), which represents the best quality RNA, or for brain sections that were ethanol-fixed and then incubated in either PBS for 5 min (hatched line) or overnight (o/n) in 2M NaCl PBS (white line). To quantify the effect of buffer condition on rRNA, the electropherogram was divided into four regions for comparison: (B) the 28S region; (C) the pre-18S region; (D) the 18S region; (E) the Inter region (see Materials and Methods for details). 28S rRNA intactness is considered a sensitive indicator of RNA integrity in general. Note, even a PBS incubation of only 5 min duration resulted in a 50% reduction in 28S area and a 120% increase in the pre-18S area. In contrast, overnight incubation in 2M NaCl or RNA Later resulted in markedly less degradation. Data are the means (+SEM). * P < 0.05, ** P < 0.01, *** P < 0.001; n ≥ 5.