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Facilitation of α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate receptor transmission in the suprachiasmatic nucleus by aniracetam enhances photic responses of the biological clock in rodents
Author(s) -
Moriya Takahiro,
Ikeda Masayuki,
Teshima Koji,
Hara Reiko,
Kuriyama Koji,
Yoshioka Tohru,
N. Allen Charles,
Shibata Shigenobu
Publication year - 2003
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2003.01758.x
Subject(s) - ampa receptor , suprachiasmatic nucleus , light effects on circadian rhythm , glutamate receptor , neuroscience , circadian rhythm , biology , neurotransmission , endocrinology , receptor , chemistry , medicine , biochemistry
This study was designed to test whether the α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate (AMPA) receptor‐facilitating drug, aniracetam, could potentiate photic responses of the biological clock in the suprachiasmatic nucleus (SCN) of rodents. Using the whole‐cell patch technique, we first demonstrated that AMPA currents elicited by either local AMPA application or optic chiasm stimulation were augmented by aniracetam in the neurons of the SCN. The AMPA application‐elicited increase of intracellular Ca 2+ concentration in SCN slices was also enhanced by aniracetam treatment. The systemic injection of aniracetam dose‐dependently (10–100 mg/kg) potentiated the phase delay in behavioral rhythm induced by brief light exposure of low intensity (3 lux) but not high intensity (10 or 60 lux) during early subjective night. Under the blockade of NMDA receptors by (+) MK801, aniracetam failed to potentiate a light (3 lux)‐induced phase delay in behavioral rhythm. Aniracetam increased the photic induction of c‐Fos protein in the SCN that was elicited by low intensity light exposure (3 lux). These results suggest that AMPA receptor‐mediated responses facilitated by aniracetam can explain enhanced photic responses of the biological clock in the SCN of rodents.