Entrainment of circadian rhythms to irregular light/dark cycles: a subterranean perspective

Author(s)

Flores, Danilo E. F. L. ; Jannetti, Milene G. ; Valentinuzzi, Veronica S. ; Oda, Gisele A.

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 6, OCT 4 2016.
• Web of Science Citations: 2

Abstract

Synchronization of biological rhythms to the 24-hour day/night has long been studied with model organisms, under artificial light/dark cycles in the laboratory. The commonly used rectangular light/dark cycles, comprising hours of continuous light and darkness, may not be representative of the natural light exposure for most species, including humans. Subterranean rodents live in dark underground tunnels and offer a unique opportunity to investigate extreme mechanisms of photic entrainment in the wild. Here, we show automated field recordings of the daily light exposure patterns in a South American subterranean rodent, the tuco-tuco (Ctenomys aff. knighti). In the laboratory, we exposed tuco-tucos to a simplified version of this natural light exposure pattern, to determine the minimum light timing information that is necessary for synchronization. As predicted from our previous studies using mathematical modeling, the activity rhythm of tuco-tucos synchronized to this mostly simplified light/ dark regimen consisting of a single light pulse per day, occurring at randomly scattered times within a day length interval. Our integrated semi-natural, lab and computer simulation findings indicate that photic entrainment of circadian oscillators is robust, even in face of artificially reduced exposure and increased phase instability of the synchronizing stimuli. (AU)

• FAPESP's process: 12/15767-2 - Laboratory and field chronobiology in subterranean rodents (Ctenomys aff. knighti)
• Grantee: Gisele Akemi Oda
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/50482-1 - Field and laboratory chronobiological studies in subterranean rodents (Ctenomys aff. knighti)
• Grantee: Gisele Akemi Oda
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/24120-0 - A lab, field and computer study of the synchronization of circadian rhythms in the subterranean rodent tuco-tuco (Ctenomys aff. knighti)
• Grantee: Danilo Eugênio de França Laurindo Flôres
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/20671-0 - Chronobiology of South American subterranean rodents, in laboratory and field
• Grantee: Gisele Akemi Oda
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/09324-6 - Field and computer simulation studies on the chronobiology of subterranean rodents (Ctenomys aff knighti)
• Grantee: Milene Gomes Jannetti
• Support Opportunities: Scholarships in Brazil - Scientific Initiation