Scanning electrochemical microscopy (SECM) was applied to the Study of the spatial distribution of the respiratory activity in a PC12 neuronal cell. The SECM imaging of the oxygen concentration around the cells indicated that the axon of PC12 as well as its cell body consumed oxygen as the result of mitochondrial respiration. The variation in respiratory activity during NGF-induced axonal growth was monitored at the growth cone of the axon. The respiratory activity at the growth cone Was found to be particularly activated by the NGF treatment. (C) 2003 Elsevier Ltd. All rights reserved.