褪黑激素对大鼠弓状核神经元自发单位放电的调制作用

[目的]研究褪黑激素(MEL)对大鼠下丘脑弓状核(ARC)神经元自发单位放电活动的影响。[方法]记录ARC神经元自发单位放电,微电泳注射MEL。分析注射MEL前和注射MEL时ARC神经元自发单位放电的放电间隔(ISI)及其变化率。[结果]微电泳MEL时,220个ARC神经元自发单位放电活动的变化有3种情况:92个单位(41.82％)的ISI减小(兴奋);61个单位(27.73％)的ISI增加(抑制);67个单位(30.45％)的ISI无明显改变(不反应)。[结论]MEL对ARC大部分神经元的自发放电活动有兴奋或抑制的调制作用,以兴奋作用为主,但对小部分神经元的自发放电活动无明显影响。

Modulation of Melatonin on Spontaneous Unit Discharges of the Arcuate Nucleus in Rats

[Objective] To study the effects of melatonin (MEL) on spontaneous unit discharges of the hypothalamic arcuate nucleus (ARC) in rats. [Methods] The spontaneous unit discharges of the ARC neurons were recorded and MEL was microiontophoretically applied. The interspike intervals (ISI) of spontaneous unit discharges before and during application of MEL and the change rates of mean ISI were analysed. [Results] During iontophoresis of MEL, the changes of spontaneous unit discharges in 220 neurons could be divided into three kinds: (1) 92 units (41. 82% ) showed decrease in ISI (excitation); (2) 61 units (27. 73% ) showed increase in ISI (inhibition); (3) 67 units (30. 45% ) had no significant change in ISI (no response). [Conclusion] The modulation of MEL on the spontaneous unit discharges in most of ARC neurons can be either excitatory or inhibitory, in which the major is excitatory. But in a small population of ARC neurons, the spontaneous unit discharges have no significant change by MEL.