Characteristics of odorant elicited calcium changes in cultured human olfactory neurons

An important step in establishing and utilizing a cell culture system for t he in vitro study of olfaction is assessing whether the cultured cells poss ess physiological properties similar to those of mature olfactory neurons. Various investigators have successfully established proliferating cell line s from olfactory tissue, but few have demonstrated the characteristics of o dor sensitivity of these cells. We successfully established cultured cell l ines from adult human olfactory tissue obtained using an olfactory biopsy p rocedure and measured their ability to respond to odor stimulation using ca lcium imaging techniques. A subset of the human olfactory cells in culture displayed a distinct morphology and specifically expressed immunocytochemic al markers characteristic of mature human olfactory neurons such as OMP, G( olf), NCAM and NST. Under defined growth conditions, these cultured cells r esponded to odorant mixes that have been previously shown to elicit intrace llular calcium changes in acutely-isolated human olfactory neurons. These o dorant-elicited calcium responses displayed characteristics similar to thos e found in mature human olfactory neurons. First, cultured cells responded with either increases or decreases in intracellular calcium. Second, increa ses in calcium were abolished by removal of extracellular calcium. Third, i nhibitors of the olfactory signal transduction cascades reversibly blocked these odorant-elicited intracellular calcium changes. Our results demonstra te that cultures of adult human olfactory cells established from olfactory biopsies retain some of the in vivo odorant response characteristics of acu tely isolated cells from the adult olfactory epithelium. This work has impo rtant ramifications for investigation of olfactory function and dysfunction using biopsy procedures and in vitro assays of odor sensitivity. J. Neuros ci. Res. 62:737-749, 2000. (C) 2000 Wiley-Liss, Inc.