The role of inositol trisphosphate-induced Ca2+ release from IP3-receptor in the rat suprachiasmatic nucleus on circadian entrainment mechanism.
Synchronization between the environmental lighting cycle and the circadian clock in the suprachiasmatic nucleus (SCN) is correlated with Ca2+ increase. The mechanism underlying the increase of Ca2+ and its relation to clock resetting are unknown. To address these issues, we examined the possibility whether inositol 1,4,5-trisphosphate receptor (IP3-R), which regulate intracellular Ca2+, was involved in the circadian rhythm component of the rat SCN. A novel IP3-induced Ca2+ release modulator, 2-amino-ethoxy diphenylborate (2APB), blocked optic nerve stimulation-induced neuronal field potentials in the SCN. Furthermore, glutamate-induced phase delay of the circadian firing pattern in the SCN was also blocked completely by 2APB in vitro. Together, these data suggest the possibility that IP3-induced Ca2+ release through IP3-R plays a role in the entrainment of the mammalian circadian clock, the SCN.
Hamada
T
T
Ishida Group of Clock Gene, National Institute of Bioscience and Human Technology, AIST, MITI, Tsukuba Science City, Japan.
Liou
S Y
SY
Fukushima
T
T
Maruyama
T
T
Watanabe
S
S
Mikoshiba
K
K
Ishida
N
N
D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D003624:Darkness; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D007839:Functional Laterality; D018698:Glutamic Acid / Q000494:pharmacology; D006706:Homeostasis; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology / Q000502:physiology*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009900:Optic Nerve / Q000502:physiology; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000502:physiology*
D001896:Boron Compounds; D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D018698:Glutamic Acid; D015544:Inositol 1,4,5-Trisphosphate; C109986:2-aminoethoxydiphenyl borate; D002118:Calcium