GABA from vasopressin neurons regulates the time at which suprachiasmatic nucleus molecular clocks enable circadian behavior
Takashi Maejima, Yusuke Tsuno, Shota Miyazaki, Yousuke Tsuneoka, Emi Hasegawa, Md Tarikul Islam, Ryosuke Enoki, Takahiro J. Nakamura, Michihiro Mieda
Abstract
Significance In mammals, the suprachiasmatic nucleus (SCN) functions as the master circadian clock to orchestrate multiple circadian biological rhythms in the body. Although almost all SCN neurons contain γ-aminobutyric acid (GABA) as a neurotransmitter, the physiological roles of GABA in the SCN network are poorly understood. We show that mice lacking GABA release specifically from arginine vasopressin (AVP)-producing neurons, one of the major neuron types in the SCN, retain an SCN that progresses normally at the clock gene level but fires aberrantly with bimodal rhythm. Accordingly, the mice demonstrate locomotor activity at inappropriate times with respect to the clock gene-based SCN clock. GABAergic transmission from AVP neurons may regulate SCN firing rhythm to modulate when SCN molecular clocks enable daily behavior.