Chemical perturbation of the temporal or spatial aspects of axonal or dendritic growth is associated with neurobehavioral deficits in animal models, and structural changes in axons and dendrites are thought to contribute to clinical symptoms associated with diverse neurologic diseases. Consequently, axonal and dendritic morphology are often quantified as functionally relevant endpoints of neurotoxicity. Here, we discuss methods for visualizing and quantifying axonal and dendritic morphology of neurons from the peripheral or central nervous systems in in vitro and ex vivo preparations. These methods include visualization of neuronal cytoarchitecture by immunostaining axon- or dendrite-selective antigens, transfecting cells with cDNA encoding fluorescent proteins, or labeling cells using membrane permeable small molecules that distribute throughout the cytoplasm, Golgi staining or Diolistics, as well as quantifying axonal and dendritic morphology using semi-automated or fully automated image analysis
