Enzyme effects on the connective tissues of an insect central nervous system

The effect of various enzymes on the two connective tissue matrices of the cockroach central nervous system were investigated. Removal of the neural lamella, using collagenase, allows some of the cells which form the perineurium to pull out of this cell layer but the perineurial bracelet cells maintain an intact blood-brain barrier. Incubation of the nerve cord with hyaluronidase has little or no effect on the neural lamella and allows the selective removal of the matrix from the glial lacunar system. Partial removal of this matrix appears to have little effect on the ability of the axons to conduct action potentials at high frequencies. In addition to this difference in susceptibility of the neural lamella and lacunar matrices to different enzymes, there appears to be a difference between the lacunar matrix of the connectives and of the ganglia, the latter being more resistant to enzyme attack. There is no such difference in the neural lamella covering the ganglia and connectives.