Retinomotor Rhythms in the Bluegill, Lepomis macrochirus

1968 ◽  
Vol 25 (2) ◽  
pp. 373-381 ◽  
Author(s):  
Kenneth R. John ◽  
David M. Gring
Keyword(s):  
Intermediate State ◽  
Lepomis Macrochirus ◽  
Constant Darkness ◽  
Artificial Light ◽  
Continuous Darkness ◽  
Free Running

Bluegills, Lepomis macrochirus, entrained to natural or artificial light–dark cycles, were confined to constant darkness for varying periods up to 42 hr at temperatures in the range 20–25 C. The retinomotor activities were determined from histological preparations. In the first night, the eyes became maximally dark-adapted within 1 or 2 hr. The pigment was contracted to a dense basal band, twin cones extended to the boundary of the pigment, and single cones extended into the pigment. After 2 or 3 hr in darkness, these components began a return toward their light-adapted positions, slowly for 5 or 6 hr, and then rapidly during the last 3 or 4 hr, and came to rest in an intermediate state of adaptation at subjective sunrise. In continuous darkness, the retina exhibited a rudimentary free-running rhythm, and there was some evidence of a 12-hr oscillation within the 24-hr period. The amplitudes of the rhythms ranged in decreasing order from twin cones to single cones to pigment and the extreme amplitudes occurred about 2 hr after sunset and at subjective sunrise. Single cones were always more extended than twin cones and only the rod-shaped particles, not the spheres, of pigment appeared to cycle. By the end of the experiment, the rhythms of cones were slightly damped and the rhythm of the pigment was greatly damped. Rods were not studied.

Gonadal hormones organize and modulate the circadian system of the rat

1981 ◽  
Vol 241 (1) ◽  
pp. R62-R66 ◽  
Author(s):  
H. E. Albers
Keyword(s):  
Testosterone Propionate ◽  
Wheel Running ◽  
Activity Rhythm ◽  
Gonadal Hormones ◽  
Circadian System ◽  
Female Rats ◽  
Constant Darkness ◽  
Before And After ◽  
Free Running ◽  
Free Running Period

The circadian wheel-running rhythms of gonadectomized adult male, female, and perinatally androgenized female rats, maintained in constant darkness, were examined before and after implantation of Silastic capsules containing cholesterol (C) or estradiol-17 beta (E). The free-running period of the activity rhythm (tau) before capsule implantation tended to be shorter in animals exposed to perinatal androgen. Administration of C did not reliably alter tau in any group. E significantly shortened tau in 100% of females injected with oil on day 3 of life. In females, injected with 3.5 micrograms testosterone propionate on day 3, and males, E shortened or lengthened tau, with the direction and magnitude of this change in tau inversely related to the length of the individual's pretreatment tau. These data indicate that the presence of perinatal androgen does not eliminate the sensitivity of the circadian system of the rat to estrogen, since estrogen alters tau in a manner that depends on its pretreatment length.

Organization of rat circadian rhythms during daily infusion of melatonin or S20098, a melatonin agonist

1999 ◽  
Vol 277 (3) ◽  
pp. R812-R828 ◽  
Author(s):  
B. Pitrosky ◽  
R. Kirsch ◽  
A. Malan ◽  
E. Mocaer ◽  
P. Pevet
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Phase Response Curve ◽  
Constant Darkness ◽  
Time Interval ◽  
General Activity ◽  
Activity Peak ◽  
Free Running ◽  
Wheel Activity ◽  
Free Running Period

Daily administration of melatonin or S20098, a melatonin agonist, is known to entrain the free-running circadian rhythms of rats. The effects of the duration of administration on entrainment were studied. The animals demonstrated free-running circadian rhythms (running-wheel activity, body temperature, general activity) in constant darkness. Daily infusions of melatonin or S20098 for 1, 8, or 16 h entrained the circadian rhythms to 24 h. Two daily infusions of 1 h (separated by 8 h) entrained the activity peak within the shorter time interval. The entraining properties of melatonin and S20098 were similar and were affected neither by pinealectomy nor by infusion of 1- or 8-h duration. However, with 16-h infusion, less than half of the animals became entrained. Once entrained, the phase angle between the onset of infusion and the rhythms (onset of activity or acrophase of body temperature) increased with the duration of infusion. Before entrainment, the free-running period increased with the duration of infusion, an effect that was not predictable from the phase response curve.

Circadian and estrous cycle-dependent variations in blood pressure and heart rate in female rats

1994 ◽  
Vol 267 (5) ◽  
pp. R1250-R1256 ◽  
Author(s):  
H. Takezawa ◽  
H. Hayashi ◽  
H. Sano ◽  
H. Saito ◽  
S. Ebihara
Keyword(s):  
Heart Rate ◽  
Estrous Cycle ◽  
Female Rats ◽  
Constant Darkness ◽  
Dark Phase ◽  
Daily Rhythms ◽  
Abrupt Decrease ◽  
Internal Phase ◽  
Free Running ◽  
Cycle Dependent

To determine whether cardiovascular functions are controlled by the endogenous circadian system and whether they change with the estrous cycle in female rats, we measured mean arterial pressure (MAP), heart rate (HR), and spontaneous activity (ACT) of female rats using an implantable radiotelemetry device and a computerized data-collecting system. Under a 12:12-h light-dark (LD) cycle, these parameters exhibited daily rhythms that were entrained to the photic cycle. The patterns of the daily rhythms varied with estrous cycles, and variations were particularly marked in the proestrous stage. During the dark period of this stage, ACT levels were significantly higher, but HR was significantly lower than in other stages. Although the peak MAP occurred within 2 h after the onset of the dark phase in three of the estrous stages, it occurred around midnight in the proestrous stage. Such estrous cycle-dependent variations were eliminated by ovariectomy. The implantation of 17 beta-estradiol produced a gradual increase in MAP and an abrupt decrease in HR. During constant darkness, all three parameters were free running, maintaining the same internal phase relationships with each other as during LD cycles. These results indicate that daily variations in these parameters were controlled by the endogenous circadian oscillating system, that they vary with the estrous cycle in female rats, and that estrogen may be responsible for these estrous cycle-dependent variations.

scholarly journals Free-running circadian breathing rhythms are eliminated by suprachiasmatic nucleus lesion

2020 ◽  
Vol 129 (1) ◽  
pp. 49-57
Author(s):  
Benton S. Purnell ◽  
Gordon F. Buchanan
Keyword(s):  
Sleep Apnea ◽  
Circadian Rhythms ◽  
Suprachiasmatic Nucleus ◽  
Time Of Day ◽  
Sudden Unexpected Death ◽  
Constant Darkness ◽  
Unexpected Death ◽  
Treatment And Prevention ◽  
Free Running

It has long been appreciated that breathing is altered by time of day. This study demonstrates that rhythmicity in breathing persists in constant darkness but is dependent on the suprachiasmatic nucleus in the hypothalamus. Understanding circadian rhythms in breathing may be important for the treatment and prevention of diseases such as sleep apnea and sudden unexpected death in epilepsy.

Maternal-fetal communication of circadian phase in a precocious rodent, the spiny mouse

1987 ◽  
Vol 253 (4) ◽  
pp. E401-E409
Author(s):  
D. R. Weaver ◽  
S. M. Reppert
Keyword(s):  
Circadian Rhythms ◽  
Postnatal Period ◽  
Spiny Mouse ◽  
Constant Darkness ◽  
Suprachiasmatic Nuclei ◽  
Maternal Influences ◽  
Circadian Phase ◽  
Environmental Light ◽  
Running Activity ◽  
Free Running

The development of circadian rhythms was examined in a precocious rodent species, the spiny mouse. Spiny mouse pups born and reared in constant darkness expressed robust circadian rhythms in locomotor activity as early as day 5 of life. Free-running activity rhythms of pups born and reared in constant darkness were coordinated with the dam on the day of birth. Postnatal maternal influences on pup rhythmicity are minimal in this species, as pups fostered on the day of birth to dams whose circadian phases were opposite to the pups' original dams were coordinated with their original dams on the day of birth. Studies using 2-deoxy-D-[1-14C]-glucose autoradiography showed that there were synchronous (coordinated) rhythms in metabolic activity in the maternal and fetal suprachiasmatic nuclei, directly demonstrating prenatal coordination of maternal and fetal rhythmicity. Maternal-fetal coordination of circadian phase was not the result of direct entrainment of the fetuses to the environmental light-dark cycle. These results demonstrate that there is prenatal communication of circadian phase in this precocious species, without demonstrable postnatal maternal influences on pup circadian rhythmicity. Spiny mice therefore represent an important animal model in which circadian rhythms in the postnatal period can be used to precisely assess prenatal influences on circadian phase.

Factors affecting perithecial production in Gibberella (Fusarium) tricincta

1979 ◽  
Vol 57 (22) ◽  
pp. 2497-2500 ◽  
Author(s):  
N. E. El-Gholl ◽  
C. L. Schoulties ◽  
W. H. Ridings
Keyword(s):  
Mass Culture ◽  
Basal Medium ◽  
Continuous Light ◽  
Colony Growth ◽  
Constant Darkness ◽  
Continuous Darkness ◽  
Hedera Helix ◽  
Pigment Formation ◽  
Factors Affecting ◽  
Leaf Spots

Three pigmentation types (brown, red, and white) of Fusarium tricinctum (Corda) Sacc. were observed when an isolated mass culture from leaf spots on English ivy (Hedera helix L.) was single spored. Perithecia of the heterothallic fungus Gibberella tricincta El-Gholl were produced at 20 and 27 °C on stem pieces of Cynodon dactylan Pers. resting on water agar, under 12-h alternating light and dark when certain pigmentation types were paired. Pairing of red and brown pigmentation types yielded significantly (P < 0.05) more perithecia than red and white pairings at 20 and 27 °C. Perithecia were formed only in combinations of red with brown or white pigmentation types. In both sets of pairings, significantly (P < 0.05) more perithecia were produced at 27 than at 20 °C. No perithecia were formed in constant darkness. Occasionally, the red pigmentation type became white after subsequent transfers and never reverted to the red pigmentation on various media and failed to produce perithecia with any pigmentation type. Continuous darkness slightly favored red pigment formation over continuous light as detected by the Munsell color codes. Increasing temperatures from 20 to 32 °C decreased the colony growth diameter of the red-pigmented cultural type. At 32 °C a change in hue was noted with corresponding changes in color codes. Red mycelial pigmentation was intensified by the addition of copper, iron, manganese, and zinc to a basal medium. The addition of 0.1% yeast extract favored mycelial development and caused a more pronounced red mycelial pigmentation in the presence of heavy metals.

Biological alarm clock arouses hibernating big brown bats, Eptesicus fuscus

1987 ◽  
Vol 65 (7) ◽  
pp. 1668-1674 ◽  
Author(s):  
John W. Twente ◽  
Janet Twente
Keyword(s):  
Laboratory Study ◽  
Eptesicus Fuscus ◽  
Continuous Darkness ◽  
Exogenous Variables ◽  
Alarm Clock ◽  
Big Brown Bats ◽  
Free Running ◽  
The Times ◽  
The Individual

This laboratory study showed that the individual averages of the times of day of arousal from hibernation of 55 big brown bats, Eptesicus fuscus, maintained in darkness, ranged from 14:05 to 20:50 (2:05 p.m. to 8:50 p.m.). The data were interpreted as representing a persistent but inexact 24-h rhythm that functioned as a biological alarm clock. This rhythm was, according to the parameters measured, apparent only on the day of arousal. The rhythm was determined to be independent of the length of time the bat had hibernated; independent of temperature; persistent and did not drift and become free-running in continuous darkness; unapparent in daily cardiac patterns or themogenic activity; and independent of obvious exogenous variables.

A circadian rhythm of behavioural thermoregulation in a freshwater gastropod, Helisoma trivolis

1980 ◽  
Vol 58 (11) ◽  
pp. 2152-2155 ◽  
Author(s):  
Martin Kavaliers
Keyword(s):  
Circadian Rhythm ◽  
Constant Darkness ◽  
Dark Phase ◽  
Behavioural Thermoregulation ◽  
Dark Cycle ◽  
Preferred Temperature ◽  
Temperature Selection ◽  
Freshwater Gastropod ◽  
Free Running ◽  
Maximum Temperatures

The behaviour of the aquatic gastropod Helisoma trivolis was examined in a thermal gradient. Under a 12 h light: 12 h dark cycle gastropods displayed a diel rhythm of preferred temperature selection. Maximum temperatures (21–22 °C) were selected during the dark phase and minimum temperatures (17–18 °C) were selected during the light phase of the light–dark cycle. Under constant darkness temperature selection continued as an endogenous free-running circadian rhythm of behavioural thermoregulation.

EFFECTS OF PINEALECTOMY AND CONSTANT LIGHT AND DARKNESS ON PROLACTIN LEVELS IN THE PITUITARY AND PLASMA AND ON PITUITARY ULTRASTRUCTURE OF THE RAT

1972 ◽  
Vol 54 (2) ◽  
pp. 263-NP ◽  
Author(s):  
R. RELKIN ◽  
M. ADACHI ◽  
S. A. KAHAN
Keyword(s):  
Plasma Concentrations ◽  
Virgin Female ◽  
Female Rats ◽  
Constant Light ◽  
Constant Darkness ◽  
Plasma Prolactin ◽  
Continuous Darkness ◽  
Prolactin Content ◽  
Intermediate Degree ◽  
Pituitary Prolactin

SUMMARY The effects of constant light, constant darkness and diurnal lighting, in combination with pinealectomy or sham-pinealectomy, on pituitary and plasma concentrations of radioimmunoassayable prolactin were investigated in 8-week-old male and virgin female rats. Two to three days after operation random groups of pinealectomized and sham-pinealectomized animals of the same sex were placed together in either continous light, continuous darkness or diurnal light, and killed 21 days later. Compared with sham-operated diurnally-illuminated controls, constant darkness caused a decrease in pituitary prolactin content and a rise in plasma prolactin levels. Pinealectomy or constant illumination reversed the effect of constant darkness, resulting in an increase in pituitary prolactin content and a fall in plasma prolactin levels when compared with sham-operated diurnally-illuminated controls. Electron microscopy of lactotrophic cells of the sham-pinealectomized animals exposed to constant darkness revealed few cytoplasmic granules, whereas these cells in the sham-pinealectomized animals exposed to constant light contained abundant granules; compared with the former groups, lactotrophic cells of sham-pinealectomized rats exposed to diurnal lighting revealed an intermediate degree of granulation.

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