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Modulation of circadian rhythm of discharges of suprachiasmatic nucleus neurons in rat hypothalamic slices by melatonin
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- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 3
- DOI:
- 10.3321/j.issn:0371-0874.2000.03.009
- Key Word:
- 视交叉上核;松果腺切除;褪黑素;下丘脑薄片;昼夜节律;luzindole;哌唑嗪
Abstract： 先用持续光照和松果腺切除预处理大鼠, 然后制成下丘脑薄片, 记录其视交叉上核(SCN)神经元的自发放电, 观察其昼夜变化和褪黑素(MEL)对它的影响.实验结果表明: (1)在正常光照(光照∶黑暗=12∶12)条件下, SCN神经元自发放电频率呈现昼高夜低的节律性.在昼夜时间(CT)6～8出现放电高峰, 频率约为8.3 Hz; 在CT18～20出现低谷, 频率约为3.8 Hz.松果腺切除后, SCN神经元自发放电的昼夜节律性基本保持, 但在持续光照条件下, 昼夜节律基本消失.(2) SCN神经元对MEL反应以抑制为主.在正常光照条件下, 在白昼SCN神经元对MEL反应性较高, 最大抑制率在CT8～10, 约为42%; 在黑夜较低, 最大抑制率在CT22～24, 约为26%.在持续光照和松果腺切除条件下, SCN神经元都失去对MEL反应的昼夜节律性,且反应性增高.(3) ML-1受体拮抗剂luzindole能阻断由MEL引起的SCN神经元自发放电抑制, 而ML-2受体拮抗剂哌唑嗪却不能阻断.实验结果提示, 松果腺作为大鼠昼夜节律组构的一个调整器, 通过MEL作用于SCN中的高亲和性ML-1受体, 在反应的两个时间窗口(CT8～10和CT22～24)调节SCN的昼夜节律活动.
- [1]V M, Cassone,M H, Roberts,R Y, Moore.Melatonin inhibits metabolic activity in the rat suprachiasmatic nuclei.[J].1987,81(1-2).
- [2]S, Feldman,N, Dafny.Effects of cortisol on unit activity in the hypothalamus of the rat.[J].1970,27(3).
- [3]Robert Mason.The effects of continuous light exposure on Syrian hamster suprachiasmatic (SCN) neuronal discharge activity in vitro[J].1991,123(2).
- [4]M L, Dubocovich.Pharmacology and function of melatonin receptors.[J].1988,2(12).
- [5]S J, Starkey,M P, Walker,I J, Beresford,etc.Modulation of the rat suprachiasmatic circadian clock by melatonin in vitro.[J].1995,6(14).
- [6]Shigenobu Shibata,Yuh Liou Shyh,Showa Ueki,etc.Influence of environmental light-dark cycle and enucleation on activity of suprachiasmatic neurons in slice preparations[J].1984,302(1).
- [7]L, Tamarkin,S M, Reppert,D C, Klein.Regulation of pineal melatonin in the Syrian hamster.[J].1979,104(2).
- [8]J T, Laitinen,E, Castren,O, Vakkuri,etc.Diurnal rhythm of melatonin binding in the rat suprachiasmatic nucleus.[J].1989,124.
- [9]R A, Hoffman,R J, Reiter.Rapid pinealectomy in hamsters and other small rodents.[J].1965,153(1).
- [10]Guang-Di Yu,Benjamin Rusak,Hugh D. Piggins.Regulation of melatonin-sensitivity and firing-rate rhythms of hamster suprachiasmatic nucleus neurons: constant light effects[J].1993,602(2).
- [11]Shin-ichiT.Inouye,HiroshiKawamura.Characteristics of a circadian pacemaker in the suprachiasmatic nucleus[J].1982,146(2).
- [12]J H, Meijer,W J, Rietveld.Neurophysiology of the suprachiasmatic circadian pacemaker in rodents.[J].1989,69.
- [13]Starkey SJ.Melatonin and 5-hydroxytryptamine phase-advance the rat circadian clock by activation of nitric oxide synthesis.[J].1996,211(3).
- [14]A J, McArthur,A E, Hunt,M U, Gillette.Melatonin action and signal transduction in the rat suprachiasmatic circadian clock: activation of protein kinase C at dusk and dawn.[J].1997,138(2).