Two types of increases in free Ca2+ evoked by odor in isolated frog olfactory receptor neurons.
Olfactory transduction involves second messenger-related enzymes and cAMP-gated, K+ and Ca2+ channels, which are known to be regulated by Ca2+. We report here that cytosolic free Ca2+ concentration ([Ca2+]i) in olfactory receptor neuron was increased by odorants or forskolin and Ca2+ influx contributed to the adaptation. The increases in [Ca2+]i were below two to three-fold of resting level and transient for 26 s (mean value, n = 18). The increases were due to two pathways: Ca2+ influx and release. The slow increases in [Ca2+]i by forskolin resembled those by citralva. It was suggested that the responses to citralva were accompanied by increases in intracellular cAMP and Ca2+ influx or release leading to transient increases in [Ca2+]i.
Sato
T
T
Life Electronics Research Center, Electrotechnical Laboratory, Amagasaki, Japan.
Hirono
J
J
Tonoike
M
M
Takebayashi
M
M
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D016257:Fura-2; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009570:Nitriles / Q000494:pharmacology; D009812:Odorants; D009833:Olfactory Pathways / Q000187:drug effects; D011892:Rana catesbeiana; D011984:Sensory Receptor Cells / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D013050:Spectrometry, Fluorescence
D009570:Nitriles; D005576:Colforsin; C054764:citralva; D000242:Cyclic AMP; D002118:Calcium; D016257:Fura-2