The changes in calcium ion activity during communication, development, and normal function of the olfactory system

The G protein-coupled receptors (GPCRs) found in the olfactory system play a key role in the modulation of Ca2+ activities. The complex intracellular Ca2+ transient and long-term Ca2+ oscillations affect the development, survival, response, and connection of the olfactory neurons and interneurons. The olfactory system is used as a research model because of its unique regenerative capabilities within the otherwise permanent central neuron system of adulthood. Chapter 2 looked at the Ca2+ activity induced by PACAP primarily through the PACAP-specific GPCRs in neonatal mouse olfactory bulb granule cell layer interneurons. The PACAP dose is recognized to be essential in the evaluation of PACAP modulation of Ca2+ activity. Furthermore, the numbers of PACAP responsive granule cells significantly increased between postnatal day one and five suggesting PACAP-induced Ca2+ activity is important in neonatal development. Chapter 3 looked at the Ca2+ fluxes induced by ATP through ATP specific GPCRs in olfactory epithelial (OE) sustentacular cells, which then communicate with other OE cells partially through gap junctions. The research on sustentacular cells has provided additional evidence that these cells are glial cells that coordinate the functions of neurons and basal cells in addition to fellow sustentacular cells. Chapter 4 looked at the presentation of the downstream associates of the olfactory receptors (ORs) type of GPCRs found on olfactory sensory neurons in OE. The centrin gene, Cetn2, was found to have an important role in the trafficking and localization of the proteins involved in the downstream elevation of Ca2+ activity. In the absence of Cetn2, the OR downstream protein associates adenylate cyclase III and cyclic nucleotide-gated channel, which were supposed to be transported by the nonmuscle myosin II to the OSN dendritic knob, were absent. The Cetn2 mutants show the failure to recruite the myosin in question. The resulting cilia defect disrupted the normal functions of multiple organs. All three projects have provided insights into the GCPR-inducedCa2+ activity modulations and the characterizations of Ca2+ activities in the normal functions of the olfactory system.