Rate of disappearance of isethionic acid in the rat central nervous system

The rates of disappearance of tritiated isethionic acid (2-hydroxyethanesulfonic acid) in eight regions of the rat central nervous system were studied. By utilizing the technique of graphical analysis (curve peeling), it was determined that seven areas (striatum, diencephalon, pons-medulla, midbrain, hippocampus, spinal cord, and cortex) exhibited triphasic (fast, intermediate, and slow) disappearance rates while only the cerebellum displayed a biphasic (fast, slow) rate. The half-lives for the fast component in the different regions of the central nervous system varied from 0.5 hr (midbrain and cortex) to 1.5 hr (diencephalon, cerebellum, and spinal cord); the half-lives for the intermediate component of the triphasic rate varied from 3.5 hr in the midbrain and spinal cord to 5.5 hr in the hippocampus. Half-lives estimated for the slow component of the multiphasic rate of disappearance of tritiated isethionic acid (³H]ISA) varied from 28 hr (cerebellum) to 90 hr (spinal cord).