The dendritic complexity and innervation of submandibular neurons in five species of mammals.

I have compared the dendritic complexity and innervation of homologous parasympathetic ganglion cells in several closely related species of mammals. In the smaller of these species (mouse, hamster, and rat), submandibular ganglion cells generally lack dendrites altogether and are innervated by a single axon. In the guinea pig, a somewhat larger species, these neurons possess rudimentary dendritic arbors and are innervated by 2 axons, on average. In the largest species investigated, the rabbit, submandibular ganglion cells have moderately complex dendritic arbors and receive innervation from several axons. These findings, together with a previous study of sympathetic ganglion cells in these same species (Purves and Lichtman, 1985a), indicate that relationships among neuronal morphology, convergent innervation, and animal size are widespread in the autonomic nervous system of mammals.