Aguilar-Roblero Raúl, Mercado Clara, Alamilla Javier, Laville Antonio, Díaz-Muñoz Mauricio
Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apdo. Postal 70-253, México D.F. 04510, Mexico.
Eur J Neurosci. 2007 Aug;26(3):575-82. doi: 10.1111/j.1460-9568.2007.05679.x.
Ryanodine-sensitive intracellular Ca2+ channels (RyRs) are present in suprachiasmatic nuclei (SCN) neurons, but the functions served by these channels are not known. Here we addressed whether mobilization of intracellular Ca2+ stores through the RyRs may be a link between the molecular clock and the firing rate in SCN neurons. Activation of the RyRs by administration of either 1 mM caffeine or 100 nM ryanodine increased the firing frequency, whereas inhibition of RyRs by 10 microM dantrolene or 80 microm ryanodine decreased firing rate. Similar results were obtained in experiments conducted at either midday or midnight. Furthermore, these effects were not mediated by synaptic transmission as blockade of GABA A, AMPA and NMDA receptors did not prevent the excitatory or inhibitory effects induced by either dose of ryanodine on SCN firing. We conclude that gating of RyRs is a key element of the intricate output pathway from the circadian clock within SCN neurons in rats.
对兰尼碱敏感的细胞内钙离子通道（兰尼碱受体，RyRs）存在于视交叉上核（SCN）神经元中，但这些通道的功能尚不清楚。在此，我们探讨了通过兰尼碱受体动员细胞内钙库是否可能是分子时钟与SCN神经元放电频率之间的联系。给予1 mM咖啡因或100 nM兰尼碱激活兰尼碱受体可增加放电频率，而用10 μM丹曲林或80 μM兰尼碱抑制兰尼碱受体则降低放电频率。在中午或午夜进行的实验中也得到了类似结果。此外，这些效应不是由突触传递介导的，因为阻断GABAA、AMPA和NMDA受体并不能阻止任一剂量的兰尼碱对SCN放电诱导的兴奋或抑制作用。我们得出结论，兰尼碱受体的门控是大鼠SCN神经元内生物钟复杂输出途径的关键要素。
