XO activation is required for increased Nox activity in response to IH.

<p>A) Time course of IH on XO and Nox activity. Squares represent significant increase in XO and Nox activity at 5 and 10 cycles of IH respectively. B) Effect of XO inhibitor, Allopurinol (ALLO; 10 μM) on Nox activity in PC12 cells exposed to 10 cycles (IH₁₀) and 60 cycles (IH₆₀) of IH or normoxia (N). C) Effect of Xanthine/XO (250 μM/0.01 U/mL) treatment on Nox activity under normoxic conditions with and without ALLO. Data is presented as mean ± S.E.M from four independent experiments. ** p<0.01; * p< 0.05; ns: not significant.