A comparison of enzyme patterns in the granular and molecular layers of the rabbit cerebellar cortex.

The exploration of cerebellar function has been hampered by a disproportionately low emphasis on cerebellar biochemistry. While pathways of several cerebellar nerve fibers t~-ls and of the sites of their synaptic contacts ~ have been successfully traced by ultrastructural methods l,l°,16.t7,:~e.zl, studies focusing on cerebellar enzyme activities ~,:~,1:~.1~,'-'~ and subcellular organelles ~',6'e° have been relatNely scarce. Although, as one isolated example, the 7-aminobutyric acid system has been studied in cerebella of several speciesg, r~ and the synthesis of 7-aminobutyric acid shown to occur in Purkinje axon terminals 9, a comprehensive study of the intracellular localization of a complete set o f 'marker enzymes" has not been reported. K uriyama et al. ~~ measured the levels of glutamic decarboxylase in the molecular and granular layers of the cerebellum of the rabbit while Robins et al. "-~', Hirsch 1:~ and, more recently. Shuter et al. 3~ determined the levels of several hydrolytic enzymes in the granular and molecular layers of the cerebellum of several mammalian species. Recently, wc carried out a similar study which we describe in the present report. A preliminar~ account of some of the findings has appeared "-'~.