Age-dependent changes in acetylcholinesterase activity in the primary somatosensory cortex of the cat

Abstract

As cortical reorganization in cat somatosensory cortex has been shown to be age-dependent and acetylcholinesterase and acetylcholine have been implicated in the shaping of sensory responses during the developmental process, we decided to investigate the biochemical changes that occur in acetylcholinesterase during postnatal development of the primary somatosensory cortex in normal cat. Somatosensory cortices were removed from cats at various ages between 4 and 144 postnatal days. Three fractions (total, membrane-bound and soluble) were analyzed for activity (esterase assay and sedimentation analysis) and amount of acetylcholinesterase (electrophoresis). Results indicated that both esterase activity levels and amounts were characterized by 4 distinct phases which included a large step increase in all fractions between postnatal days 10 and 12; a gradual rise between days 12 and 28; a ‘dip’ during the 42- to 82-day interval, and a subsequent recovery. Results may be attributed to concomitant developmental events. Furthermore, we suggest that the observed changes may relate to age-dependent differences in somatosensory cortex reorganization that occur after spinal cord transection.