Effect of proxyphylline and benzopyrones on the cerebrocortical NAD/NADH redox state and reflectance in haemorrhagic shock.

The effect of 7-(2-hydroxypropyl)theophylline (proxyphylline) and coumarin (Theokal) on cerebrocortical NAD/NADH redox state and vascular volume was investigated in cats in haemorrhagic shock. The influence of these drugs on cortical NADH and UV reflectance responses induced by nitrogen breathing and electrical stimulation of the cortex was also studied. The results are summarized as follows: 1. Proxyphylline administration does not change the cortical vascular volume but shifts the NAD/NADH redox state towards oxidation. This occurs in spite of the significant arterial blood pressure drop. 2. Coumarin dilates the cerebrocortical vessels and increases the cerebral blood flow. Since NAD reduction was obtained though CBF increased, it is presumed that coumarin increased the rate of glycolysis and the lactate/pyruvate ratio. 3. Proxyphylline increased, coumarin decreased the amplitude of the anoxic NAD reduction. The stimulation induced NAD and reflectance reactions were not effected by coumarin. 4. Finally it is concluded that the beneficial effect of Theokal on brain circulation and metabolism in haemorrhagic shock is related with different mechanisms to both substances, proxyphylline and 5,6-benzo-alpha-pyrone.