Circadian control of sleep-related neuronal activity in lizards

Sho T Yamaguchi; Sena Hatori; Koki T Kotake; Zhiwen Zhou; Kazuhiko Kume; Sam Reiter; Hiroaki Norimoto

doi:10.1093/pnasnexus/pgad481

Circadian control of sleep-related neuronal activity in lizards

PNAS Nexus. 2023 Dec 29;3(1):pgad481. doi: 10.1093/pnasnexus/pgad481. eCollection 2024 Jan.

Authors

Sho T Yamaguchi¹, Sena Hatori¹, Koki T Kotake¹, Zhiwen Zhou¹, Kazuhiko Kume², Sam Reiter³, Hiroaki Norimoto¹

Affiliations

¹ Department of Cellular Pharmacology, Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan.
² Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.
³ Computational Neuroethology Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, Okinawa 904-0495, Japan.

Abstract

Although diurnal animals displaying monophasic sleep patterns exhibit periodic cycles of alternating slow-wave sleep (SWS) and rapid eye movement sleep (REMS), the regulatory mechanisms underlying these regular sleep cycles remain unclear. Here, we report that in the Australian dragon Pogona vitticeps exposed to constant darkness (DD), sleep behavior and sleep-related neuronal activity emerged over a 24-h cycle. However, the regularity of the REMS/SWS alternation was disrupted under these conditions. Notably, when the lizards were then exposed to 12 h of light after DD, the regularity of the sleep stages was restored. These results suggest that sleep-related neuronal activity in lizards is regulated by circadian rhythms and that the regularity of REMS and SWS cycling is influenced by daytime light exposure.

Keywords: Pogona vitticeps; REMS/SWS alternation; circadian rhythms.