Simultaneous recording of [Ca2+]i increases in isolated olfactory receptor neurons retaining their original spatial...

A new method is described for isolating olfactory receptor neurons suitable for simultaneous recording of odorant responses in several cells. This method, called "tissue printing" by Cassab and Varner, was used to isolate cells for measurement of odorant-induced increases in cytosolic-free calcium concentration ([Ca2+]i) using the Ca2+ indicator dye fura-2. A large number of receptors could be isolated from a piece of olfactory epithelium (about 300 microns square), preserving their normal morphology and relative local topology to that in the intact olfactory tissue. The probability that there are one or more receptor cells with odorant-induced responses in [Ca2+]i per preparation was 4 times higher with cells isolated by the tissue printing than with those obtained by the pipetting method. The responses of 2 receptor cells separated by 28 microns in the recording chamber differed for 2 odorants: isoamyl acetate and citralva. The method was useful for isolating receptor neurons without losing their morphological features and for investigating the spatial distribution of odorant responsiveness of each receptor over the olfactory epithelium.