Relationships Between Photoperiodism and Circadian Rhythms of Activity in the House Finch

1967 ◽  
Vol 46 (1) ◽  
pp. 43-61 ◽  
Author(s):  
W. M. HAMNER ◽  
J. T. ENRIGHT

1. The Bunning hypothesis proposes that many rhythmic physiological processes, including photoperiodic responsiveness, are all based upon a single, endogenous circadian time-measuring system (‘die physiologische Uhr’). We have attempted to test this hypothesis by examining correlations between the circadian waking-sleeping rhythm of the house finch (Carpodacus mexicanus), and the circadian rhythm of sensitivity to light, which underlies the photoperiodic testicular responses of this species. 2. Experimental techniques included (1) comparisons of locomotor activity patterns induced by specific non-daily light cycles which stimulate gametogenesis (LD 6:30 and 6:54) with those induced by other cycles which are non-inductive (LD 6:18, 6:42 and 6:66); (2) comparisons of gametogenesis resulting from light cycles which produce large phase-lead in the activity rhythms and thereby result in photic stimulation late in the ‘subjective day’ (LD 6:20 and 3:23) with results from similar cycles which cause no phase lead (LD 6:16 and 3:19); and (3) comparisons of gametogenesis under free-running (unsynchronized) conditions in which a 6 hr. stimulus was intermittently administered early in the ‘subjective day’, with other treatments in which the same stimulus was administered late in the ‘subjective day’. 3. In all experimental series, when only group responses are considered, there were clear and strong correlations between testicular growth and the patterns observed in locomotor activity. The nature of the large intra-group variability, however, convinces us that the Bünning hypothesis, as here interpreted, is inadequate to account for all the results. Either the two circadian rhythms may be independent, similar systems; or, if there is a single ‘master clock’, the two manifestations of this timing system are apparently not phase-locked under artificial laboratory conditions. It is not clear to us how these two alternatives are experimentally distinguishable.

2007 ◽  
Vol 292 (3) ◽  
pp. R1306-R1314 ◽  
Author(s):  
Mary Harrington ◽  
Penny Molyneux ◽  
Stephanie Soscia ◽  
Cheruba Prabakar ◽  
Judy McKinley-Brewer ◽  
...  

The cycle length or period of the free-running rhythm is a key characteristic of circadian rhythms. In this study we verify prior reports that locomotor activity patterns and running wheel access can alter the circadian period, and we report that these treatments also increase variability of the circadian period between animals. We demonstrate that the loss of a neurochemical, neuropeptide Y (NPY), abolishes these influences and reduces the interindividual variability in clock period. These behavioral and environmental influences, from daily distribution of peak locomotor activity and from access to a running wheel, both act to push the mean circadian period to a value < 24 h. Magnitude of light-induced resetting is altered as well. When photoperiod was abruptly changed from a 18:6-h light-dark cycle (LD18:6) to LD6:18, mice deficient in NPY were slower to respond to the change in photoperiod by redistribution of their activity within the prolonged dark and eventually adopted a delayed phase angle of entrainment compared with controls. These results support the hypothesis that nonphotic influences on circadian period serve a useful function when animals must respond to abruptly changing photoperiods and point to the NPYergic pathway from the intergeniculate leaflet innervating the suprachiasmatic nucleus as a circuit mediating these effects.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dušan Kolarski ◽  
Carla Miró-Vinyals ◽  
Akiko Sugiyama ◽  
Ashutosh Srivastava ◽  
Daisuke Ono ◽  
...  

AbstractThe circadian clock controls daily rhythms of physiological processes. The presence of the clock mechanism throughout the body is hampering its local regulation by small molecules. A photoresponsive clock modulator would enable precise and reversible regulation of circadian rhythms using light as a bio-orthogonal external stimulus. Here we show, through judicious molecular design and state-of-the-art photopharmacological tools, the development of a visible light-responsive inhibitor of casein kinase I (CKI) that controls the period and phase of cellular and tissue circadian rhythms in a reversible manner. The dark isomer of photoswitchable inhibitor 9 exhibits almost identical affinity towards the CKIα and CKIδ isoforms, while upon irradiation it becomes more selective towards CKIδ, revealing the higher importance of CKIδ in the period regulation. Our studies enable long-term regulation of CKI activity in cells for multiple days and show the reversible modulation of circadian rhythms with a several hour period and phase change through chronophotopharmacology.


2019 ◽  
Author(s):  
Kimberley F. Prior ◽  
Aidan J. O’Donnell ◽  
Samuel S. C. Rund ◽  
Nicholas J. Savill ◽  
Daan R. van der Veen ◽  
...  

AbstractInfection can dramatically alter behavioural and physiological traits as hosts become sick and subsequently return to health. Such “sickness behaviours” include disrupted circadian rhythms in both locomotor activity and body temperature. Host sickness behaviours vary in pathogen species-specific manners but the influence of pathogen intraspecific variation is rarely studied. We examine how infection with the murine malaria parasite, Plasmodium chabaudi, shapes sickness in terms of parasite genotype-specific effects on host circadian rhythms. We reveal that circadian rhythms in host locomotor activity patterns and body temperature become differentially disrupted and in parasite genotype-specific manners. Locomotor activity and body temperature in combination provide more sensitive measures of health than commonly used virulence metrics for malaria (e.g. anaemia). Moreover, patterns of host disruption cannot be explained simply by variation in replication rate across parasite genotypes or the severity of anaemia each parasite genotype causes. It is well known that disruption to circadian rhythms is associated with non-infectious diseases, including cancer, type 2 diabetes, and obesity. Our results reveal that disruption of host circadian rhythms is a genetically variable virulence trait of pathogens with implications for host health and disease tolerance.


1986 ◽  
Vol 22 (3) ◽  
pp. 420-422 ◽  
Author(s):  
Douglas E. Docherty ◽  
Renee I. Romaine Long

2003 ◽  
Vol 285 (5) ◽  
pp. R939-R949 ◽  
Author(s):  
Christopher S. Colwell ◽  
Stephan Michel ◽  
Jason Itri ◽  
Williams Rodriguez ◽  
J. Tam ◽  
...  

The related neuropeptides vasoactive intestinal peptide (VIP) and peptide histidine isoleucine (PHI) are expressed at high levels in the neurons of the suprachiasmatic nucleus (SCN), but their function in the regulation of circadian rhythms is unknown. To study the role of these peptides on the circadian system in vivo, a new mouse model was developed in which both VIP and PHI genes were disrupted by homologous recombination. In a light-dark cycle, these mice exhibited diurnal rhythms in activity which were largely indistinguishable from wild-type controls. In constant darkness, the VIP/PHI-deficient mice exhibited pronounced abnormalities in their circadian system. The activity patterns started ∼8 h earlier than predicted by the previous light cycle. In addition, lack of VIP/PHI led to a shortened free-running period and a loss of the coherence and precision of the circadian locomotor activity rhythm. In about one-quarter of VIP/PHI mice examined, the wheel-running rhythm became arrhythmic after several weeks in constant darkness. Another striking example of these deficits is seen in the split-activity patterns expressed by the mutant mice when they were exposed to a skeleton photoperiod. In addition, the VIP/PHI-deficient mice exhibited deficits in the response of their circadian system to light. Electrophysiological analysis indicates that VIP enhances inhibitory synaptic transmission within the SCN of wild-type and VIP/PHI-deficient mice. Together, the observations suggest that VIP/PHI peptides are critically involved in both the generation of circadian oscillations as well as the normal synchronization of these rhythms to light.


Author(s):  
Joanna C. Chiu ◽  
Kwang Huei Low ◽  
Douglas H. Pike ◽  
Evrim Yildirim ◽  
Isaac Edery

2007 ◽  
Vol 7 ◽  
pp. 203-212 ◽  
Author(s):  
Ann E. K. Kosobud ◽  
Andrea G. Gillman ◽  
Joseph K. Leffel ◽  
Norman C. Pecoraro ◽  
G. V. Rebec ◽  
...  

Circadian rhythms prepare organisms for predictable events during the Earth's 24-h day. These rhythms are entrained by a variety of stimuli. Light is the most ubiquitous and best known zeitgeber, but a number of others have been identified, including food, social cues, locomotor activity, and, most recently drugs of abuse. Given the diversity of zeitgebers, it is probably not surprising that genes capable of clock functions are located throughout almost all organs and tissues. Recent evidence suggests that drugs of abuse can directly entrain some circadian rhythms. We have report here that entrainment by drugs of abuse is independent of the suprachiasmatic nucleus and the light/dark cycle, is not dependent on direct locomotor stimulation, and is shared by a variety of classes of drugs of abuse. We suggest that drug-entrained rhythms reflect variations in underlying neurophysiological states. This could be the basis for known daily variations in drug metabolism, tolerance, and sensitivity to drug reward. These rhythms could also take the form of daily periods of increased motivation to seek and take drugs, and thus contribute to abuse, addiction and relapse.


2019 ◽  
Vol 110 (1-2) ◽  
pp. 35-49 ◽  
Author(s):  
Talia Levitas-Djerbi ◽  
Dana Sagi ◽  
Ilana Lebenthal-Loinger ◽  
Tali Lerer-Goldshtein ◽  
Lior Appelbaum

Background: Hypothalamic neurotensin (Nts)-secreting neurons regulate fundamental physiological processes including metabolism and feeding. However, the role of Nts in modulation of locomotor activity, sleep, and arousal is unclear. We previously identified and characterized Nts neurons in the zebrafish hypothalamus. Materials and Methods: In order to study the role of Nts, nts mutant (nts–/–), and overexpressing zebrafish were generated. Results: The expression of both nts mRNA and Nts protein was reduced during the night in wild-type zebrafish. Behavioral assays revealed that locomotor activity was decreased during both day and night, while sleep was increased exclusively during the nighttime in nts–/– larvae. Likewise, inducible overexpression of Nts increased arousal in hsp70:Gal4/uas:Nts larvae. Furthermore, the behavioral response to light-to-dark transitions was reduced in nts–/– larvae. In order to elucidate potential contenders that may mediate Nts action on these behaviors, we profiled the transcriptome of 6 dpf nts–/– larvae. Among other genes, the expression levels of melanin-concentrating hormone receptor 1b were increased in nts–/– larvae. Furthermore, a portion of promelanin-concentrating hormone 1 (pmch1) and pmch2 neurons expressed the nts receptor. In addition, expression of the the two zebrafish melanin-concentrating hormone (Mch) orthologs, Mch1 and Mch2, was increased in nts–/– larvae. Conclusion: These results show that the Nts and Mch systems interact and modulate locomotor activity and arousal.


Neuroscience ◽  
2013 ◽  
Vol 237 ◽  
pp. 151-160 ◽  
Author(s):  
T. Kikuchi ◽  
H. Tan ◽  
T. Mihara ◽  
K. Uchimoto ◽  
D. Mitsushima ◽  
...  

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