The coupling features of electrical synapses modulate neuronal synchrony in hypothalamic superachiasmatic nucleus.
Electrical synapses (gap junctions) exist in many types of neurons in the mammalian brain, especially during early development period; one of the most important roles of electrical synapses is to mediate the synchrony of the neuronal networks and to coordinate the neural circuits function precisely. Previous reports show that electrical coupling is involved in modulating synchronous activity among coupled neurons, but related dynamics and mechanisms are still poorly understood. Here, in order to investigate the correlation between gap junctions and synchrony we focus on the electrically coupled neurons in suprachiasmatic nucleus (SCN) by using calcium imaging with two-photon microscopy and electrophysiology. We observed that coupled neurons in SCN present a dynamic regulation on synchrony based on their coupling strengths and are modulated by vasoactive intestinal peptide (VIP) - a neuropeptide whose receptors are expressed throughout the SCN. Modification of coupling efficiency of electrical synapses changes the synchrony level of the neuronal networks in the SCN. Our results provide new insights into the causal relationship between gap junctions and synchrony in the SCN. We further demonstrate the importance of VIP in coordinating the gap junctions-mediated signal transmission and implicate that a homeostasis environment is important for SCN to modulate the rhythmic circadian activities.
Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China; University School of the Chinese Academy of Sciences, Beijing 100049, China.
Ming-Hui
MH
Wang
Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China.
Na
N
Chen
Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China. Electronic address: jhw@sun5.ibp.ac.cn.
Jin-Hui
JH
Wang
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D054351:Electrical Synapses / Q000502:physiology*; D017629:Gap Junctions / Q000502:physiology*; D066298:In Vitro Techniques; D051379:Mice; D008815:Mice, Inbred Strains; D018613:Microscopy, Confocal; D009474:Neurons / Q000502:physiology*; D061848:Optical Imaging; D018408:Patch-Clamp Techniques; D013493:Suprachiasmatic Nucleus / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
D014660:Vasoactive Intestinal Peptide
Coupling coefficient; Electrical synapse; Neuronal network; Suprachiasmatic nucleus; Synchrony; Vasoactive intestinal peptide