Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons.
In toad olfactory neurons, a putrid odorant mixture inducing inhibitory responses increases Ca2+-activated K+ conductance, developing a hyperpolarizing receptor potential. Removal of extracellular Ca2+ or exposure to nifedipine reversibly reduced the inhibitory response, suggesting that odorants induce a Ca2+ influx. We show evidence for an odorant-induced Ca2+ current. Using confocal microscopy, it is shown that odorants induce a nifedipine-sensitive elevation of Ca2+ in the apical end of the cell. These results suggest an inhibitory mechanism in which an apical Ca2+ influx causes an increase in internal Ca2+, opening Ca2+-activated K2+ channels that lead to membrane hyperpolarization.
Morales
B
B
Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago.
Madrid
R
R
Bacigalupo
J
J
D000818:Animals; D001001:Anura; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology*; D015220:Calcium Channels / Q000502:physiology*; D003712:Dendrites / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D009543:Nifedipine / Q000494:pharmacology; D009812:Odorants; D009831:Olfactory Mucosa / Q000294:innervation; D018034:Olfactory Receptor Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques
D015220:Calcium Channels; D009543:Nifedipine; D002118:Calcium