Integration of the biowarning information through the hypothalamic neuronal network.

研究应激对大鼠摄食量和下丘脑外侧区(LHA)神经活动的影响。在固定2小时后，观察到每日摄食量显著减少。甲基丝氨酸乙酯(5 mg/kg，i.p.)注射纳洛酮3小时可对抗制动所致的厌食症，但不起作用。为研究LHA神经元对束缚应激的反应，采用慢性埋线电极记录单个神经元的活动。束缚应激可使20个LHA神经元中的16个神经元的活动明显降低。平均放电频率(放电/秒)从基线的27.1+-2.4下降到8.1；+-1.0，平均潜伏期为20.1&lt；+-5.2分钟。在本研究中，NO神经元在制动后增加了它们的放电率。制动前60min注射甲基丝氨酸甲酯(5 mg/kg)可完全阻断制动的抑制作用。I…更多的n 5个神经元接受甲基丝氨酸的影响，所有的反应都被预先注射甲基丝氨酸拮抗(注射甲基丝氨酸后神经放电变化-67.8+-lt；+-gt；5.4%，注射甲基丝氨酸后-19.6+-gt；6.2%)。采用碳纤维电极差示脉冲伏安法或脑微渗析高效液相色谱电化学检测法测定5-羟色胺代谢产物5-羟吲哚乙酸(5-HIAA)的含量。束缚应激后LHA中5-HIAA浓度显著升高。大鼠制动后，LHA中5-HIAA浓度迅速升高。在开始固定45分钟后，增加的水平达到最大值46.3；正负8.3%。电化学信号在固定化停止后立即逐渐衰减，并在180min内恢复到固定化前的水平。这些结果表明，制动引起的厌食症至少部分是通过5-羟色胺能机制在H。

The effects of stress on food intake and on neural activity in the lateral hypothalamic area (LHA) were investigated. Significant reduction of daily food intake was observed after 2 hr immobilization. Injection of methysergide (5 mg/kg, i.p.) antagonized the immobilization-induced anorexia for 3 hr, while injection of naloxone had no effect. To study LHA neuronal responses to immobilization stress, single neuron activity was recorded by chronically implanted wire electrodes. Activity of 16 of 20 LHA neurons were significantly decreased by immobilization stress. The mean firing rate (discharges/sec) decreased from a baseline of 27.1 <plus-minus> 2.4 to 8.1 <plus-minus> 1.0 during immobilization, and the mean latency to the steady .state response was 20.1 <plus-minus> 5.2 min. No neurons increased their firing rate following immobilization in this study. Injection of methysergide (5 mg/kg, i.p.), 60 min before immobilization, completely blocked the suppressive effect of immobilization. I … More n 5 neurons tested for the effect of methysergide, all responses were antagonized by preinjection of methysergide (-67.8 <plus-minus> 5.4% change in neural discharge by immobilization without methysergide, arnd -19.6 <plus-minus> 6.2% after injection of methysergide). Further more differential pulse voltammetry with a carbon fiber electrode or brain microdialysis with high-performance liquid chromatography and electrochemical detection were used to measure 5-hydroxyindoleacetic acid (5-HIAA), the metabolic product of the serotonin. A significant increase in 5-HIAA concentration in the LHA was detected after immobilization stress. Immobilization of rats resulted in rapid increase of 5-HIAA concentration in the LHA. The increased levels reached a maximum of 46.3 <plus-minus> 8.3% 45 min after starting the immobilization. The electrochemical signals gradually decayed immediately after cessation of immobilization and returned to the preimmobilization level within 180 min. These results suggest that immobilization-induced anorexia is mediated at least in partly through serotoninergic mechanisms in the h Less