Fig. 4. Nitrous oxide treatment alone induces neither apoptosis nor increases in levels of BACE and Aβ in H4-APP cells. (  A ) Effects of 70% nitrous oxide on caspase-3 activation. Each band in the Western blot represents an independent experiment. (  B ) Quantification of Western blot, normalized to β-actin levels. We have averaged results from three independent experiments. (  C ) Effects of the nitrous oxide treatment on apoptosis. We have averaged results from six independent experiments. (  D ) Effects of the nitrous oxide treatment on BACE levels. Each band in the Western blot represents an independent experiment. (  E ) Quantification of the Western blot, normalized to β-actin levels. We have averaged results from three independent experiments. (  F ) Effects of the nitrous oxide treatment on Aβ levels. We have averaged results from six independent experiments. APP = amyloid precursor protein; Aβ=β-amyloid protein; BACE =β-site amyloid precursor protein-cleaving enzyme; FL = full length; N.S. = not significant. **  P < 0.01.