Morales B, Ugarte G, Labarca P, Bacigalupo J
Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago.
Proc Biol Sci. 1994 Sep 22;257(1350):235-42. doi: 10.1098/rspb.1994.0120.
Odorant responses of isolated olfactory neurons from the toad Caudiverbera caudiverbera were monitored by using patch-clamp techniques. Depending on the stimulus, the same neuron responded with an increase or a decrease in action potential firing. Odorants that activate the cAMP cascade in olfactory cilia increased electrical activity, caused membrane depolarization, and triggered inward currents. In contrast, odorants that do not activate the cAMP cascade inhibited electrical activity, produced membrane hyperpolarization, and activated outward currents in a dose-dependent fashion. Such currents were carried by K+ and blocked by tetraethylammonium. Similar currents were recorded from Xenopus laevis. Our results suggest that this K+ current is responsible for odorant-induced inhibition of action potential firing in olfactory neurons.
利用膜片钳技术监测了来自尾蟾（Caudiverbera caudiverbera）的分离嗅觉神经元的气味反应。根据刺激情况，同一神经元的动作电位发放会增加或减少。在嗅觉纤毛中激活cAMP级联反应的气味剂会增加电活动、引起膜去极化并触发内向电流。相反，不激活cAMP级联反应的气味剂会抑制电活动、产生膜超极化并以剂量依赖方式激活外向电流。这种电流由K+携带，并被四乙铵阻断。在非洲爪蟾（Xenopus laevis）中也记录到了类似的电流。我们的结果表明，这种K+电流是气味剂诱导嗅觉神经元动作电位发放受抑制的原因。
