Modified cobalt staining and silver intensification techniques for use with whole-mount gastropod ganglion preparations.

While silver intensification of cobalt-filled cells is a common procedure for use with many arthropod preparations, it has not been routinely applied to gastropods. Several modifications in cobalt-staining techniques currently used with gastropods along with adaptations of silver intensification techniques used in insects are described. Cobalt was introduced into cells through axonal filling of cut nerve trunks or by either pressure injection or iontophoresis from intracellular, micropipette electrodes that had previously had their tips etched in dilute hydrofluoric acid. Etching produced consistent, sharp tips with large lumina. Further procedural modifications allowed complete, even intensification of neurons in large gastropod ganglia. These techniques have proved to be reliable and apparently broadly applicable, having been successfully used on three diverse gastropod species.