Calcium oscillations in the olfactory nonsensory cells of the goldfish, Carassius auratus.
BACKGROUND
The olfactory nonsensory cells contribute to the maintenance of normal functions of the olfactory epithelium (OE). Specifically, the ciliated nonsensory cells of teleosts play important roles in the odorant detection by OE in aqueous environment. Their cilia show strong beating activities and cause water flow at the OE surface, making the detection of odorants by OE more efficient. Because intracellular Ca2+ level has been reported to play an important role in ciliary beating, the ciliary beating activity may be regulated by intracellular Ca2+ dynamics of these ciliated nonsensory cells.


METHODS
We performed Ca2+ imaging experiments to analyze the Ca2+ dynamics in acutely dissociated OE cells of the goldfish. Furthermore, we examined the contribution of the Ca2+ dynamics to the ciliary beating frequency (CBF) at the surface of the intact OE.


RESULTS
Olfactory nonsensory cells showed both spontaneous intracellular Ca2+ oscillations and propagating intercellular Ca2+ waves. Application of 2-aminoethoxydiphenylborate (2-APB), which antagonizes IP3-induced Ca2+ release from intracellular stores suppressed these Ca2+ oscillations. Furthermore, 2-APB application to the intact OE lamellae resulted in the decrease of CBF at the surface of the OE.


CONCLUSIONS
These results indicate that spontaneous intracellular calcium oscillations persistently up-regulate the ciliary beating at the surface of the OE in teleosts.


CONCLUSIONS
Ciliary beating activity at the surface of OE can be regulated by the Ca2+ dynamics of olfactory nonsensory cells. Because this ciliary movement causes inflow of external fluid into the nostril, this regulation is suggested to influence the efficiency of odorant detection by OE.
Kawai
Takafumi
T
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Abe
Hideki
H
Wakabayashi
Ken-ichi
K
Oka
Yoshitaka
Y
D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D002923:Cilia / Q000378:metabolism / Q000502:physiology; D006054:Goldfish / Q000378:metabolism* / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D008954:Models, Biological; D009831:Olfactory Mucosa / Q000166:cytology / Q000378:metabolism*
D002118:Calcium