Circadian organization and photoreception in an Australian dasyurid marsupial (Sminthopsis macroura).

TitleCircadian organization and photoreception in an Australian dasyurid marsupial (Sminthopsis macroura).
Publication TypeJournal Article
Year of Publication1969
JournalJournal of biological rhythms
Volume2
Issue4
Pagination261-8
Date Published1969
ISSN0748-7304
Abstract

Much is known about the formal properties of circadian rhythm regulation and the physiological substrates underlying rhythmicity in nocturnal rodents, but relatively few studies have addressed circadian rhythm regulation in other mammalian taxonomic groups. In this study, some formal and functional aspects of circadian organization in a nocturnal dasyurid marsupial, the stripe-faced dunnart (Sminthopsis macroura), were analyzed. To determine phasic responses to discrete pulses of light, dunnarts were placed in constant darkness (DD) and were periodically administered pulses of bright light at different times of the animals' circadian day. Analysis of phase shifts in response to light indicated a phase response curve that was similar to responses observed in nocturnal rodents. To determine the possibility of extraretinal photoreception mediating photic entrainment, dunnarts were anesthetized and orbitally enucleated while maintained in a light-dark regimen (LD 14:10). All blinded dunnarts free-ran with periods (tau) that were similar to those observed in DD, indicating that entrainment is mediated through ocular photoreception. However, the data also indicated a decrease in activity in blind dunnarts during the last 3-5 hr of the dark phase, raising the possibility of some retention of photoreceptive capacities.

URLhttp://journals.sagepub.com/doi/full/10.1177/074873048700200402?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed
DOI10.1177/074873048700200402
Short TitleJ Biol Rhythms
X
Enter your linkblue username.
Enter your linkblue password.
Secure Login

This login is SSL protected

Loading