Schäfer K, Necker R, Braun H A
Institut für Zoophysiologie, Universität Hohenheim, Stuttgart, F.R.G.
Brain Res. 1989 Oct 30;501(1):66-72. doi: 10.1016/0006-8993(89)91027-5.
The response characteristics of facial specific cold receptors of the pigeon were studied quantitatively by recording single unit activity from the trigeminal ganglion at various stimulus conditions and subsequent analysis of the discharge pattern. Responses to maintained temperatures as well as to cooling steps were qualitatively identical to those seen in the corresponding mammalian cold receptor populations, but avian cold receptors were generally less sensitive, particularly to dynamic stimuli. The major differences between avian and mammalian cold receptors were that avian cold units only occasionally discharged in periodic groups of impulses at constant temperatures and that there was no indication of cyclic receptor events being involved in the dynamic response to cooling, as it is the case in all mammalian cold sensors. Additionally, the temporal pattern of the grouped discharges was less regular in avian cold units. Application of calcium, EGTA and menthol revealed a comparatively low dependence of cold receptor function on external calcium. The results provide evidence that calcium-controlled processes and periodic receptor events contribute only insignificantly to the signal transduction of avian cold receptors. This indicates a different functional organization of the transducer processes of avian and mammalian cold receptors.
通过在不同刺激条件下记录三叉神经节的单个神经元活动并随后分析放电模式，对鸽子面部特定冷感受器的反应特性进行了定量研究。对维持温度以及降温步骤的反应在质量上与在相应哺乳动物冷感受器群体中观察到的反应相同，但鸟类冷感受器通常不太敏感，尤其是对动态刺激。鸟类和哺乳动物冷感受器之间的主要区别在于，鸟类冷感受器单位在恒定温度下仅偶尔以周期性脉冲群的形式放电，并且没有迹象表明在对冷却的动态反应中涉及周期性感受器事件，而所有哺乳动物冷感受器都是如此。此外，鸟类冷感受器单位中分组放电的时间模式不太规则。钙、乙二醇双四乙酸（EGTA）和薄荷醇的应用表明，冷感受器功能对外部钙的依赖性相对较低。结果提供了证据，表明钙控制的过程和周期性感受器事件对鸟类冷感受器的信号转导贡献不大。这表明鸟类和哺乳动物冷感受器的换能过程具有不同的功能组织。
