We have located links that may give you full text access.
Photoperiodic time measurement and photoentrainment of a circadian locomotor activity rhythm in subtropical tree sparrows.
Photochemical & Photobiological Sciences 2017 July 2
Experiments were performed on the subtropical tree sparrow (Passer montanus) to investigate the involvement of an endogenous circadian rhythm in photoperiodic time measurement during the initiation of gonadal growth and functions and also to study the photic entrainment of the circadian activity rhythm. Groups of photosensitive birds of both sexes were exposed to different "night-interruption" light-dark regimes of 24 h duration viz., G1 - 6L/5D/1L/12D, G2 - 6L/6D/1L/11D, G3 - 6L/7D/1L/10D, G4 - 6L/8D/1L/9D, G5 - 6L/10D/1L/7D, G6 - 6L/12D/1L/5D, G7 - 6L/14D/1L/3D and G8 - 6L/16D/1L/1D for 30 days in which 17 h long nights were interrupted by 1 h light pulse falling at different ZTs (i.e., 11, 12, 13, 14, 16, 18, 20 and 22). A control group, for each sex, was maintained under 7L/17D. The birds of all groups behaved as though they had been exposed to a stimulatory photoperiod except those of G1, G8 and the control. Furthermore, the serum levels of testosterone in males and estradiol-17β in females ran almost parallel to changes in the gonadal size. Birds, when exposed to 12L/12D, showed entrainment of their locomotor activity rhythm with the activity confined mainly during the light phase. However, various characteristics of the activity rhythm differed significantly upon transfer of birds to various night interruption regimes. These results suggest the involvement of the endogenous circadian rhythm in photoperiodic time measurement during the induction of gonadal growth and functions in the tree sparrow. Also, there is photic entrainment of the locomotor activity rhythm that shows variations in various circadian characteristics under different night interruption cycles suggesting that the photoinducible phase is differentially sensitive to light.
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app