Diffusion of glucose through blood-cerebrospinal fluid barrier in normal dogs

Hyperglycorrachia was produced in anesthetized dogs by the administration of intravenous glucose. The glucose entered the lumbar subarachnoid space more rapidly than it entered the cisternal subarachnoid space. This finding is a reverse of the diffusion into the cisternal and lumbar regions in man after the administration of intravenous glucose. The pattern in dogs is different from that in man under normal circumstances, but follows the pattern present when radioactive sodium 24 is used as a diffusible substance. It is concluded that glucose diffuses directly into the spinal subarachnoid at a rapid rate in the dog. This may be due to anatomical differences in various species.