Circadian rhythm in inhibitory synaptic transmission in the mouse suprachiasmatic nucleus
Circadian rhythm in inhibitory synaptic transmission in the mouse suprachiasmatic nucleus
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DOI：
10.1152/jn.01078.2003
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发表时间：
2004-07-01
影响因子：
2.5
通讯作者：
Colwell, CS
中科院分区：
文献类型：
--
作者：
Itri, J;Michel, S;Colwell, CS
大多数视交叉上核（SCN）神经元表达神经递质GABA，并可能使用这种神经递质调节SCN内的兴奋性，这一观点已被广泛接受。为了评估小鼠SCN内抑制性突触传递随昼夜节律变化的可能性，我们在急性脑切片制备中使用全细胞膜片钳记录gaba介导的自发抑制性突触后电流（sIPSCs）。我们发现背侧SCN （dSCN）的sIPSC频率表现出ttx敏感的每日节律，在处于光：暗周期的小鼠中，该节律在白天晚些时候和晚上早些时候达到峰值。接下来，我们评估了血管活性肠肽（VIP）是否与IPSC频率中观察到的节律有关。用VPAC(1)/ VPAC(2)-或VPAC(2)特异性受体拮抗剂预处理SCN切片可阻止dSCN中sIPSC频率的增加。VIP/肽组氨酸异亮氨酸（PHI）缺乏小鼠sIPSC频率节律性缺失。最后，我们能够在持续黑暗的小鼠中检测到抑制性突触传递频率的节律，这种节律也依赖于VIP和VPAC(2)受体。总的来说，这些数据表明，在小鼠SCN背侧区域的gaba能传递中存在昼夜节律，并且这种节律的表达需要VIP。
It is widely accepted that most suprachiasmatic nucleus (SCN) neurons express the neurotransmitter GABA and are likely to use this neurotransmitter to regulate excitability within the SCN. To evaluate the possibility that inhibitory synaptic transmission varies with a circadian rhythm within the mouse SCN, we used whole cell patch-clamp recording in an acute brain slice preparation to record GABA-mediated spontaneous inhibitory postsynaptic currents (sIPSCs). We found that the sIPSC frequency in the dorsal SCN (dSCN) exhibited a TTX-sensitive daily rhythm that peaked during the late day and early night in mice held in a light: dark cycle. We next evaluated whether vasoactive intestinal peptide ( VIP) was responsible for the observed rhythm in IPSC frequency. Pretreatment of SCN slices with VPAC(1)/ VPAC(2)- or VPAC(2)-specific receptor antagonists prevented the increase in sIPSC frequency in the dSCN. The rhythm in sIPSC frequency was absent in VIP/peptide histidine isoleucine (PHI)-deficient mice. Finally, we were able to detect a rhythm in the frequency of inhibitory synaptic transmission in mice held in constant darkness that was also dependent on VIP and the VPAC(2) receptor. Overall, these data demonstrate that there is a circadian rhythm in GABAergic transmission in the dorsal region of the mouse SCN and that the VIP is required for expression of this rhythm.