Increase of cerebral blood flow produced by low dosages of cyanide

¹ Laboratory of Comparative Physiology, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México, D. F.

In cats and rabbits lightly anesthetized with pentobarbital or immobilized with Flaxedil and in encéphale isolé cats, the intravenous injection of NaCN in doses of 0.05 to 0.5 mg/kg produced a great increase in blood flow from the head (jugular vein) without any significant change in the blood flow from a hind limb (femoral vein). This would indicate that the increase in blood flow from the head was probably due to the brain and not to the nonnervous structures. This assumption was further supported by the large increase in the blood flow through the sagittal sinus. The greatest increase in jugular flow, threefold, was produced by 0.2–0.3 mg/kg of cyanide. This dose did not produce any significant change in the arterial, jugular, and femoral vein oxygen concentration, and hence in the A-V oxygen difference of head and limb. The results would indicate that the consumption of the brain is augmented by these dosages of cyanide.