Calcium Imaging in the Olfactory System: New Tools for Visualizing Odor Recognition

Abstract

Transient elevations of intracellular Ca²⁺ play an important role in regulating the sensitivity of the sense of smell, both at the level of signal transduction within the cilia of olfactory receptor neurons and at presynaptic sites in the olfactory bulb, but such elevations have not been demonstrated previously because of the small size of these neuronal com partments. Here, we summarize recent progress employing high resolution Ca²⁺-imaging techniques that permit the visualization of odor-induced neural activity in these critical subcellular compartments of the vertebrate olfactory system. In olfactory neurons, Ca²⁺ permeable cyclic nucleotide-gated (CNG) cation channels mediate the initial Ca²⁺ entry during odor transduction. The surprisingly widespread distribution of members of the CNG channel family in the mammalian brain suggests that CNG channel-mediated Ca²⁺ entry contributes to signal transduction in many CNS neurons. NEUROSCIENTIST 5:4- 7, 1999