Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, 1A Kreutzwaldi Street, 51014 Tartu, Estonia.
J Insect Physiol. 2010 Apr;56(4):412-21. doi: 10.1016/j.jinsphys.2009.11.017. Epub 2009 Dec 6.
Responses of the antennal thermosensitive neuron of the ground beetle Platynus assimilis to warming from 20 to 50 degrees C were measured and analysed. During warming, neurons switched from regular spiking to bursting. ISI analysis showed that the number of spikes in the burst and spike frequency within the burst were temperature dependent and may precisely encode unfavourably or dangerously high temperatures in a graded manner. In contrast, regular spikes of the neuron encode moderate temperatures at 20-30 degrees C. The threshold temperature of spike bursting varied in different neurons from 25 to 47 degrees C. As a result, the number of bursting neurons increased with temperature increase. Therefore, in addition to the burst characteristics, the total number of bursting neurons may also contain useful information on external temperature. A relationship between the spike bursts and locomotor activity of the beetles was found which may have importance in behavioural thermoregulation of the species. At 44.4+/-0.6 degrees C, first indications of partial paralysis (of the hind legs) were observed. We emphasize, that in contrast to various sensory systems studied, the thermoreceptor neuron of P. assimilis has a stable and continuous burst train, no temporal information is encoded in the timing of the bursts.
测定并分析了步甲 Platynus assimilis 触角热敏神经元对 20-50°C 升温的反应。升温过程中，神经元由规则放电转变为爆发式放电。ISI 分析表明，爆发中的脉冲数和爆发内的脉冲频率均与温度相关，可能以分级的方式精确编码不利或危险的高温。相比之下，神经元的规则放电则编码 20-30°C 的中等温度。不同神经元的脉冲爆发阈值温度在 25-47°C 之间变化。因此，随着温度的升高，爆发神经元的数量增加。因此，除了爆发特征外，爆发神经元的总数可能还包含有关外部温度的有用信息。我们发现，步甲的爆发与运动活动之间存在关联，这在该物种的行为体温调节中可能具有重要意义。在 44.4±0.6°C 时，观察到后腿部分瘫痪（麻痹）的初步迹象。我们强调，与已研究的各种感觉系统不同，P. assimilis 的热敏神经元具有稳定且连续的爆发式冲动，爆发的时间没有时间信息编码。
