Photoentrainment in blind and sighted rodent species: Responses to photophase light with different wavelengths

Abed E. Zubidat, Randy J. Nelson, Abraham Haim

Research output: Contribution to journalArticlepeer-review

Abstract

Our study examined the impact of daylight (photophase) wavelength on the photoentrainment sensitivity of two species with vastly different visual systems. Social voles (Microtus socialis) and 'blind' mole rats (Spalax ehrenbergi) were exposed to shortwavelength (479?nm) or long-wavelength (697?nm) light at an intensity of 293μW cm-2. Rhythms of urine production, urinary 6- sulfatoxymelatonin (6-SMT), urinary metabolites of adrenaline and cortisol, and oxygen consumption (VO2) were used as markers for the sensitivity of the photoentrainment system. Significant 24-h rhythms were detected in all variables for both species under short-wavelength light, whereas ultradian rhythms of 12- or 8-h were detected under long-wavelength light. Wavelength inversely affected 6-SMT levels in M. socialis (negative correlation) and S. ehrenbergi (positive correlation). Increased levels of stress hormone metabolites were detected in M. socialis under the long-wavelength light whereas, in S. ehrenbergi elevated levels were secreted under short-wavelength light. Long-wavelength light increased VO2 in M. socialis and decreased it in S. ehrenbergi; short-wavelength light elicited the opposite effects. Our results indicate that photophase wavelength is an integral light property for modulating photoperiodic responses in mammals, including visually challenged species. Finally, the spectral-induced differential responses between the two species potentially represent adaptive physiological flexibility in species with contrasting visual and habitat challenges.

Original languageEnglish
Pages (from-to)4213-4222
Number of pages10
JournalJournal of Experimental Biology
Volume213
Issue number24
DOIs
StatePublished - Dec 2010

Keywords

  • Cosinor analysis
  • Masking
  • Melanopsin
  • Retinal photoreceptor
  • Subterranean

ASJC Scopus subject areas

  • Insect Science
  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Physiology

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