Agrotis segetum雄蛾触角叶神经元对性信息素时间编码的机制分析

应用压力注射，在Agrotis segetum雄蛾触角叶（AL）中33个对性信息素有反应的MGC神经元上探计了对性信息素反应模式的形成机制，压力注射100mmol/L GABA进入AL神经网引起神经元一个慢的超极化电位，并有一个长时程的放电抑制相，与用性信息素刺激诱导的神经元分应很相似，但GABA并不影响神经元对性信息素刺激的去极化反应，低Cl^-溶液可减弱AL神经元对性信息素刺激的超极化反应，甚至使超极化相逆转为兴奋反应，抑制相消失。压力注射Bicuculline使神经元放电频率增加。压力注射Bicuculline的同时给予性信息素刺激，可使性信息素刺激所致的神经元放电增加进一步加强；Bicuculline可使性信息素刺激引起的神经元超极化幅度变小，放电抑制时间变短，甚至其抑制相完全被逆转为正常放电，无超极化反应和抑制相存在，结果表明，AL神经元对性信息系反应的超极化相与GABA受体有关。

Mechanism of the Biphasic Pattern of Neurons Time Coding to Sex Pheromone in the Antennal Lobe of the Male Moth Agrotis segetum

Here studied the mechanism of responded pattern of 33 neurons to sex pheromone in the antennal lobe (AL) of male moths Agrotis segetum . Pressure injecting 100 mmol/L GABA into AL, GABA can elicit inhibitory responses of slow hyperpolarization and long time inhibition of background spiking, alike which caused by sex pheromone in the same neuron. But GABA can not act on the excitation evoked by pheromone. Low Cl - saline caused that the IPSP to reverse the hyperpolarization, excitation evoked by pheromone was prolonged, and the distinct separation between bursts disappeared. Bicuculline was as a GABA A receptor antagonist in vertebrates, and a water soluble form of this agent was used for pressure ejection into the AL neuropil. Bicuculline increased the spike frequency in tested neurons, even strengthened the excitation phase acted by pheromone, and the hyperpolarization and spike inhibition produced by pheromone was replaced by excitation. The effect was reversible by washing in normal saline. Results indicate that the hyperpolarization is related to GABA receptor, which responds to the sex pheromone in AL neurons in the male moths Agrotis segetum .