Fig. 4. ( A ) Representative images of in situ superoxide production. Black dots indicate external margins of cerebral arterioles. Note increased intensity of fluorescence in the brain slice treated with d-glucose (20 mm) in arteriolar walls ( white arrows ). ( B ) Relative superoxide production in the brain slices treated with any addition of l-glucose (20 mm), d-glucose (20 mm), propofol (10−6m) in combination with d-glucose (20 mm), or Tempol (10−4m) in combination with d-glucose (20 mm) to the control solution. * Difference between the brain slices treated with d-glucose and the brain slices treated with l-glucose, difference between the brain slices treated with d-glucose and the brain slices treated with propofol in combination with d-glucose, and difference between arterioles treated with d-glucose and arterioles treated with Tempol in combination with d-glucose are statistically significant ( P < 0.05). ( C ) Relative superoxide production in the brain slices treated with any addition of d-glucose (20 mm), apocynin (1 mm) in combination with d-glucose (20 mm), propofol (10−6m) in combination with d-glucose (20 mm), or allopurinol (10−4m) in combination with d-glucose (20 mm) to the control solution. * Difference between the brain slices treated with d-glucose and the brain slices treated with apocynin in combination with d-glucose, and difference between arterioles treated with d-glucose and arterioles treated with propofol in combination with d-glucose are statistically significant ( P < 0.05).