Fig. 4.

Chronic hypoxia increases colocalization among smooth muscle contractile proteins. As revealed by confocal microscopy, MLCK-SMαA colocalization was 42% greater in hypoxic than normoxic fetal arteries. Similarly, MLC₂₀-SMαA colocalization was 42% greater and MLCK-MLC₂₀ colocalization was 123% greater in hypoxic than normoxic fetal arteries. All these differences were statistically significant and suggest that the contractile proteins were becoming more compact and highly organized in response to chronic hypoxia. UR%, percentage of pixels in upper right quadrant. Values are means ± SE; n ≥ 5 in all experimental groups. *P < 0.05 by ANOVA.