title: The chronomutagenic effect of deuterium oxide on the period and entrainment of a biological rhythm. II. The reestablishment of lost entrainment by artificial LD cycles.
abstract: Mice caused to ingest 25% or 30% deuterium oxide could no longer be entrained to a 12:12 light-dark cycle. Reentrainment could be established by artificially lengthening the light-dark cycle from a natural 24-hours one, to LD 13:13 or 14:14. It is noted that the relationship between biological rhythms and the ambient LD cycle is strikingly similar to that between coupled unidirectional physical oscillators. It is concluded that while the similarity between the responses of a great many organismic rhythms to deuterium oxide administration suggests that the biological clocks of all organisms are very similar, if not the same, a substance with more specificity to key biological processes than D2O will be required to eventually elucidate the escapement mechanism of the enigmatic living clock.
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000187:drug effects*; D003624:Darkness; D003903:Deuterium / Q000494:pharmacology*; D008027:Light; D008297:Male; D051379:Mice / Q000502:physiology*
chemical_list: D003903:Deuterium