ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 1943-03-01
    Print ISSN: 0016-1152
    Topics: Chemistry and Pharmacology
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 175 (1994), S. 75-82 
    ISSN: 1432-1351
    Keywords: Circadian ; Rhythm ; Pineal ; Pacemaker Retina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Exposure to constant light abolishes circadian behavioral rhythms of locomotion and feeding as well as circulating melatonin rhythms in pigeons (Columba livia). To determine if feeding rhythmicity could be maintained in pigeons exposed to constant light, periodic infusions (10h/day) of melatonin were administered to pinealectomized and bilaterally retinectomized/pinealectomized pigeons under conditions of both constant darkness and constant light. The infusions were sufficient to entrain rhythmicity in pinealectomized pigeons in constant darkness and to restore and maintain rhythmicity in bilaterally retinectomized/pinealectomized pigeons in constant darkness. On subsequent exposure to constant light, rhythmicity remained phase locked to the melatonin infusions in bilaterally retinectomized/pinealectomized pigeons but was abolished in sighted pinealectomized birds. These results suggest that while endogenous melatonin rhythms are both necessary and sufficient to maintain behavioral rhythms in DD, their effect can be overridden by constant light but only if perceived by the eyes. Thus, constant light may abolish behavioral rhythmicity in intact pigeons (and perhaps in other species) by a mechanism other than suppression of endogenous melatonin rhythmicity. Such a mechanism might involve direct stimulation of locomotor or feeding activity by retinally perceived (but not by extra-retinally perceived) light, or alternatively by suppression of a hypothalamic oscillator that receives its major light input from the retinae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 175 (1994), S. 223-232 
    ISSN: 1432-1351
    Keywords: Suprachiasmatic nucleus ; Circadian rhythms ; Body temperature ; Locomotor activity ; Syrian hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The effects of suprachiasmatic and control lesions on the circadian rhythms of locomotor activity and body temperature were studied in golden hamsters (Mesocricetus auratus) maintained in constant light as well as constant darkness. Large suprachiasmatic lesions, but not control lesions, eliminated circadian rhythmicity in locomotor activity as well as in body temperature. Analysis of the “robustness” of the rhythms of locomotor activity and body temperature in unlesioned and lesioned animals suggests that, because body temperature rhythmicity is more robust than locomotor rhythmicity, lesions that spare a small number of suprachiasmatic cells might abolish the latter but not the former. Our results do not support the hypothesis that the body temperature rhythm is controlled by a circadian pacemaker distinct from the main pacemaker located in the suprachiasmatic nuclei.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 179 (1996), S. 135-142 
    ISSN: 1432-1351
    Keywords: Daily rhythms ; Iguana iguana ; Behavioral thermoregulation ; Parietal eye ; Pineal gland ; Melatonin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Daily variation in the body temperature of the green iguana (Iguana iguana) was studied by telemetry in laboratory photo-thermal enclosures under a 12Light∶12Dark (L∶D) photoperiod. The lizards showed robust daily rhythms of thermoregulation maintaining their body temperatures (Tb) at higher levels during the day than during the night. Some animals maintained rhythmicity when kept in constant darkness. On light∶dark cycles parietalectomy produced only a transient increase of median Tb in the first or second night following the operation. Pinealectomized lizards on the other hand maintained their body temperatures at significantly lower levels during the day and at significantly higher levels during the night than did sham-operated or intact lizards. This effect was apparently permanent, since one month after pinealectomy lizards still displayed the altered pattern. Plasma melatonin levels in intact animals were high during the night and low during the day and were unaffected by parietalectomy. Pinealectomized lizards showed low levels of plasma melatonin during both the day and the night. A daily intraperitoneal injection of melatonin in pinealectomized animals given a few minutes after the light to dark transition decreased the body temperatures selected by the lizards during the night and increased the body temperatures selected during the following day. Control injections of saline solution had no effect. The significance of these results is discussed in relation to the role of the pineal complex and melatonin in the mediation of thermoregulatory behavior.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 169 (1991), S. 39-50 
    ISSN: 1432-1351
    Keywords: Photoreception ; Retinally degenerate ; Mouse ; Circadian ; Rods ; Cones ; 11-cis retinaldehyde ; Immunocytochemistry ; HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We have examined the effects of light on circadian locomotor rhythms in retinally degenerate mice (C57BL/6J mice homozygous for the rd allele: rd/rd). The sensitivity of circadian photoreception in these mice was determined by varying the irradiance of a 15 min light pulse (515 nm) given at circadian time 16 and meauring the magnitude of the phase shift of the locomotor rhythm. Experiments were performed on animals 80 days of age. Despite the loss of visual photoreceptors in the rd/rd retina, animals showed circadian responses to light that were indistinguishable from mice with normal retinas (rd/+ and +/+). While no photoreceptor outersegments were identified in the retina of rd/rd animals (80–100 days of age), we did identify a small number of perikarya that were immunoreactive for cone opsins, and even fewer cells that contained rod opsin. Using HPLC, we demonstrated the presence and photoisomerization of the rhodopsin chromophore 11-cis retinaldehyde. The rd/rd retinas contained about 2% of 11-cis retinaldehyde found in +/+ retinas. We have yet to determine whether the opsin immunoreactive perikarya or some other unidentified cell type mediate circadian light detection in the rd/rd retina.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 126 (1943), S. 127-127 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...