Carbonic anhydrase distributions in central and peripheral nervous system of the rat.

Total and specific carbonic anhydrase activity was measured for 24 structures of the rat central and peripheral nervous system. In the CNS, white matter or regions containing largely white matter show a neuraxial distribution of enzyme activity; more cephalad structures display more activity. Gray matter regions do not show a rostrocaudal distribution and usually have lower activity than adjacent myelin-containing structures. PNS tissue shows neither the white-gray differences nor the rostrocaudal profile of CNS tissue. Subcellular fractionation of 18 regions of the CNS suggest that the predominance of membrane-bound carbonic anhydrase (60% of the total activity and independent of its magnitude) is a unique characteristic of all regions of the central nervous system.