REGULATION OF PROTEIN-KINASE-C ACTIVITY BY SENSORY DEPRIVATION IN THEOLFACTORY AND VISUAL SYSTEMS

Environmental regulation of sensory function has provided an important model of plastic mechanisms mediating neural information processing. To define potential commonalities in information processing in differe nt systems, we investigated molecular changes elicited by sensory depr ivation in the developing rat olfactory and visual systems. Protein ki nase C (PKC), an intracellular messenger implicated in synaptic plasti city and memory, was analyzed. Initial, developmental studies indicate d that PKC activity in the soluble and particulate fractions of the ol factory bulb increased three- to fourfold from birth to 3 months of ag e. Unilateral olfactory deprivation prevented the developmental increa se in both soluble and particulate PKC activities in the ipsilateral o lfactory bulb and piriform cortex, the second-order relay. Phorbol est er binding localized PKC to intrinsic neuronal populations and their d endrites in the control and deprived bulbs. Moreover, PKC was similarl y lower in the visual cortex of dark-reared rats than in light-reared controls. The changes in PKC were region specific, as activity was unc hanged by either treatment in the parietal cortex, a control area that does not process primary olfactory or visual information. Our results suggest that the important intracellular messenger, PKC, is similarly regulated in entirely different sensory systems by different environm ental stimuli. Consequently, different sensory systems may use common molecular mechanisms to process information.