Neuron geometry and circuitry via the electron microscope: Intracellular staining with osmiophilic polymer

Intracellularly injected cobalt catalyzes the generation of an osmium-binding polymer from 3,3′-diaminobenzidine in neurons of Aplysia californica. Excellent structural preservation of nervous tissue is coupled with easy recognition of fine branches of the injected neurons in the electron microscope. This permits detailed structural analysis of synaptology.