Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HIBERNATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 865 records · Page 48Linked to original sources
PubMed1990

[Seasonal changes in seminiferous tubules and Leydig cells of hibernating bats].

We studied the seasonal course of Leydig cells combined with spermatogenesis and blood testosterone concentrations. The reproductive cycle of Pipistrellus kuhli kuhli and Eptesicus serotinus is characterized by seminiferous tubules which reactivate after a period of complete quiescence extending for the whole winter hibernating sleep and spring (March-June) periods. During hibernation, Leydig cells show ultrastructural features which stress a low secretory activity with corresponding low concentration of blood testosterone. With the beginning of summer, Leydig cells increase their metabolic activity reaching a top in the mating season (fall) when also blood testosterone and spermatogenesis reach the highest levels. The authors, after some comparative morphological considerations with different hibernating animals, assert that the reproductive processes of these two bats are not strictly species-linked, but rather dependent, besides seasonal thermal changes, upon habitat and feeding sources.

Animals↗
PubMedDate not supplied

[Lipid levels and lipid peroxidation in frog tissues during hyperthermia and hibernation].

The content of cholesterol, phospholipids, free fatty acids in the blood, ketone bodies and lipid peroxidation in the liver, brain, myocardium, skeletal muscles of Rana ridibunda were studied. Changes in the lipid content in blood during artificial hypothermia differ from those during hibernation and arousal. The utilization of reserve fats during hibernation is limited, but significantly rises during arousal. The ability to spontaneous lipid peroxidation under conditions of homogenate incubation at 37 degrees C does not increase in the studied tissues during hibernation.

Animals↗
PubMed1985

Lithium suppresses hibernation in the Turkish hamster.

Daily uptake of lithium salt (LiCl) in the drinking water at a rate of over 100 micrograms/g b.wt (or 2.4 mEq/kg) reduced or suppressed natural torpidity (hibernation) in the Turkish hamster (Mesocricetus brandti). The data indicate a direct influence of lithium on clock-related functions controlling the hibernation process rather than indirect effects by preventing gonadal regression and thereby also hibernation.

Animals↗
PubMedDate not supplied

[Activation of protein synthesis in tissues of gophers after arousal from hibernation].

Intensity of the protein synthesis is studied in cells of different organs and tissues of hibernating, arousing and active gophers and rats. It is established that during hibernation a level of labelled aminoacids incorporation into proteins of all organs under study (ventricle, auricle, liver, spleen, diencephalon, adrenal gland, brown fatty tissue) is inconsiderable. The protein synthesis intensity essentially grows after animals arousing and their body temperature elevation, ten times exceeding the level of the studied process in hibernating gophers. Rate of precursors' incorporation in cell proteins of active gophers and rats is 3-4 times lower than in arousing rodents. The same regularity is revealed when studying rates of labelled amino acids incorporation into slices of the above organs and tissues.

Amino Acids↗
PubMed1985

Cytochemical variations in Purkinje neuron nuclei of cerebellar areas with different afferent systems in Rana esculenta. Comparison between activity and hibernation.

The distribution pattern of the Feulgen-DNA values (nuclear cytochemical heterogeneity) which provides information on the functional state of Purkinje neurons was investigated in the lobus vestibularis and in the corpus cerebelli in active and hibernating frogs. In the corpus cerebelli, hibernation does not change greatly the nuclear heterogeneity of Purkinje neurons, while in the lobus vestibularis this neuron population becomes more homogeneous and shows more condensed chromatin. These data suggest a nerve conduction in the two areas which responds differently to the phenomenon of hibernation, entailing a lower activity of Purkinje neurons in the lobus vestibularis with respect to the corpus cerebelli. Furthermore, the examination of a portion of the vestibular nuclear complex revealed an opposite behavior: indeed, a higher homogeneity of the nuclear cytochemical patterns was observed during activity. This result is related to the function of this localization as center of stimuli integration.

Afferent Pathways↗
PubMed1985

Cycles of body fat in hibernators.

This paper reviews data on seasonal changes in body fat of mammalian hibernators. It then presents data on the fat cell number and size in the retroperitoneal and gonadal fat depots of dormice, Glis glis, over the course of their body weight cycles. Enlargement of fat cell size is the principal way that hibernators get fat. The hibernator cycle may provide a way of discovering whether regulation of fat level is achieved through regulation of total mass of fat or through regulation of the size of existing adipocytes.

Adipose Tissue↗
PubMed1979

[Interaction between Karyolysus sp. and rock lizard liver cells during hibernation].

During the rock lizard hibernation, no nuclear division occurs in the exoerythrocytar trophozoites of Karyolysus sp., found in hepatocytes or Kupffer's cells. In addition, organelles of the apical complex are seen persisting in these trophozoites, unlike the situation routinely observed in the majority of other intracellular sporozoans. Thus, the parasites under study can be compared with hypnozoites of other coccidia. The material being examined from natural rather than experimental conditions, during lizards' hibernation, the dynamics of host-parasite interrelations can be followed that involves the appearance in the infected cell of autophagous vacuoles, changes in mitochondrial structure and pattern of endoplasmic reticulum, the connection of the system of lamellar channels with the space of the parasitophorous vacuole. The results of the present observations may suggest, first, that during the host hibernation, exoerythrocytar trophozoites of Karyolysus being intracellular in their spatial distribution, are able to obtain nutrients from the outer, extracellular space, through the system of lamellar channels; second, that these channels can represent intercellular connections, which makes one consider the exoerythrocytar trophozoites as intercellular rather than intracellular parasites.

Animals↗
PubMed1981

Seasonal changes in pituitary-adrenal reactivity in hibernating spermophiles.

Basal level of 11-hydroxycorticosteroids in plasma was measured during one year period in spermophiles and correlated with a physiological state of the animals. Maximum level was found in Spring after the animals had awaken from hibernation, while a minimum level was observed during hibernation. During the waking up process the level of corticosteroids increased slowly which may show that this process does not act as a stressor. In contrast, the falling asleep process starts under a decreased level of corticosteroids in plasma and is accompanied by a further decrease. Maximum stimulatory effect of adrenaline and isoprenaline on pituitary-adrenal axis was found after waking up in Spring. It was considerably less in Summer, while no such effect was found before hibernation period. However, at the same time the sensitivity of adrenals to ACTH was sufficient. From this it may be concluded that seasonal changes in pituitary-adrenal response to catecholamines may be due to changes in central regulatory mechanisms.

Adrenal Cortex Hormones↗
PubMed1984

[Changes the structural elements of the organs of bats during periods of activity and hibernation].

In hibernated animals (Myotis myotis) morphological changes are characterized by certain peculiarities in structure of the mitochondrial apparatus and some other cellular organells. In the animals, which are in the state of hibernation, the main plan of cardiomyocytes structure in the pulmonary vein wall, as well as in the myocardium itself does not change, as compared to those in the animals which are in the active state. The ultrastructure of the skeletal muscle fibers also does not undergo any essential alterations. A definitely seen narrowing of the capillary bed in the pulmonary alveoli is revealed. In the nuclei of their granular cells chromatin is substituted for lamellar myelin-like corpuscles; in cytoplasm there are inclusions that contain electron-opaque material of lamellar structure. In the active animals the inclusions contain electron-transparent material and are surrounded with a wide osmiophilic rim. In the liver of the hibernating animals hepatocytes loose their glycogen, but the number of lipid vacuoles and electron-opaque multivesicular corpuscles increase.

Animals↗
PubMedDate not supplied

[Primary sleep in vertebrates and its role in the genesis of hypobiosis in poikilotherms and hibernation in mammals].

New data are presented on the homology between winter hibernation and hypobiosis in poikilotherms, as well as one of the resting forms of the primary sleep in vertebrates. Different stages of formation of a cycle "awakefulness-sleep" in evolution of vertebrates are discussed. On the basis of universal behavioural, somato-vegetative, neurophysiological, neurochemical correlates of resting forms, hypobiosis and winter hibernation, a discussion is made of the problem of genetic fixation in the genotype and phenotype of heterothermic mammals (hibernating ones) of those characters which are typical of the sleep in homoiothermic and poikilothermic vertebrates.

Amphibians↗
PubMedDate not supplied

Replication of Mycobacterium leprae in hibernating ground squirrels (Citellus tridecemlineatus).

Subcutaneous injections of 10(6) acid-fast bacteria from human lepromatous tissue to hibernating ground squirrels (Citellus tridecemlineatus) is followed by generalized infection of the animals and spontaneous death. The number of mycobacteria is high in the skin of GS during winter and decreases during summer. Animals surviving the first hibernation period invariably die during the second. The number of microorganism in the visceral organs is low at all times. The system of infected hibernating GS is a valuable model for the experimental study of leprosy.

Animals↗
PubMed1980

Water metabolism and renal function during hibernation and hypothermia.

Total water turnover in normothermic, cold-exposed 13-lined ground squirrels was about half that predicted from allometric relationships of water loss and body weight. During hibernation pulmocutaneous water loss and oxygen consumption were 1/77th and 1/52nd of values during normothermia, respectively, in this species. Renal function during deep torpor with body temperatures of 8 C or lower has also been assessed in ground squirrels and hamsters. The weight of evidence suggests that glomerular filtration and urine formation are absent of undetectable in these animals. We feel that the reduction in arterial blood pressure may be the primary adaptation for eliminating filtration. If filtration (which is not thermally vulnerable, being dependent on hydrostatic pressure) occurred, it is difficult to imagine how reabsorption (which has critical metabolic steps such as ion transport that would be thermally vulnerable) could keep pace. Filtration and hypertonic urine formation occur at body temperatures of 20 to 30 C during the arousal process. Marmots differ from other hibernating rodents in that measurable filtration and hypertonic urine formation occurs during hibernation.

Animals↗
PubMed1982

[Phosphorylase activity in Rana ridibunda tissue during hibernation, prolonged hypothermia and heating].

Essential seasonal changes are found in the total activity of phosphorylase and the activity of its forms in the Rana ridibunda tissues. They are mostly pronounced in the liver and myocardium tissues. A week hibernation (2-4 degrees C) and artificial hypothermia (2-4 degrees C) of the same duration cause changes of different direction in the phosphorylases a and b ratio in the musculus trapezius and myocardium of frogs. Healing after hypothermia, as distinct from heating after hibernation, increases the enzyme total activity in all the tissues under study as well as the phosphorylase alpha activity in the skeletal muscles and myocardium. When the animal awakes from hibernation the enzyme activity increases only in the liver tissue due to the inactive form.

Animals↗
PubMed1995

[Modulation of norepinephrinergic control of hypothalamus preoptic areas on hibernation bouts in ground squirrels (Citellus dauricus)].

In our previous work, it was shown that hibernation could be enhanced by injection of 6-hydroxydopamine (6-OHDA, 200 micrograms) into the lateral cerebral ventricle of ground squirrels by destructing norepinephrine (NE) nerve terminals in brain areas including hypothalamus, cerebral cortex, hippocampus and periaqueductal gray matter of middle brain. In order to identify the specific area contributing for the modulation of NE system on hibernation, small doses of 6-OHDA (4 micrograms) were microinjected bilaterally into medial preoptic hypothalamus (MPA), lateral preoptic hypothalamus (LPA) and ventromedial hypothalamic nucleus (VMH). The results showed: (1) Depletion of NE on MPA may facilitate hibernation. (2) Little effect was seen by microinjection of 6-OHDA into LPA. (3) The effect of 6-OHDA on VMH was similar to that on MPA, through the mechanism remains to be investigated.

Animals↗
PubMedDate not supplied

[Amino acid transport and protein synthesis in ground squirrels during hibernation and artificial hypothermia].

The intensity of labelled leucine penetration from the blood-circulating system to the tissues and its incorporation into proteins of some organs of gophers have been studied under hibernation and hypothermia. It is shown that, in spite of the low temperature of the gopher body under hibernation, the intensity of amino acids transfer from the blood to the tissue was approximately the same as in active state. But the rate of proteins synthesis under hibernation considerably decreases though it is not completely stopped. Under artificial hypothermia of the mammals the transition of amino acids from the blood to the tissue is considerably hampered. Under these conditions the incorporation of labelled amino acids is completely stopped.

Amino Acids↗
PubMed1993

[Analysis of the protein/polypeptide in Culex pipiens pallens (Diptera:Culicidae) during hibernation by two-dimensional gel electrophoresis].

Analysis on the protein/polypeptide in Culex pipiens pallens (Diptera: Culicidae) caught from the resting or overwintering places during the 3rd ten-day of September, the 2nd ten-day of December and the 1st ten-day of March in next year in Zhengzhou (34 degrees 43' N, 113 degrees 39' E) during hibernation by two-dimensional gel electrophoresis indicated that there were 153, 118 and 169 protein/polypeptide spots in unoverwintering, overwintering and recovering mosquitoes respectively. The molecular weight (MW) of most of the spots was less than 43.0 kDa, with isoelectric points (pI) between 5.65-7.34. The comparisons between each two types of mosquitoes during hibernation revealed that the variant rate of protein/polypeptide spots between overwintering and recovering mosquitoes (31.01%) was significantly higher than that between unoverwintering and recovering females (21.12%) (P < 0.05). The variant spots were 13 in unoverwintering, 7 in overwintering and 27 in recovering mosquitoes respectively. The comparisons among three types of mosquitoes during hibernation showed that the variant rate was significantly higher in recovering females (15.98%) than in unoverwintering (8.50%) (P < 0.05) and overwintering females (5.93%) (P < 0.01). The total variant rate of protein/polypeptide spots of all these three types of mosquitoes was 10.68%. Because the blood meal of all the mosquitoes used for homogenization was at Sella 1 (empty), and the ovary development was under Christophers II (resting stage), the experimental results were not affected by blood meal and the later ovary development (Christophers II-V).

Animals↗
PubMedDate not supplied

[The recovery of the sleep-wakefulness cycle during arousal from hibernation in the long-tailed Arctic suslik Citellus parryi].

New data and analysis are presented concerning the recovery of the sleep cycle during onset of deep winter hibernation (T brain = 3 degrees C) and arousal from hibernation in the Arctic ground squirrel at temperatures of the brain 3-35 degrees C. It was shown that natural arousal from hibernation is associated with gradual development of the sleep phases on a basis of the resting forms which are typical of the lower level of development of the central nervous system in vertebrates.

Animals↗
PubMedDate not supplied

[The role of the central nervous system in controlling hibernation].

Bibliographic and original experimental data related to the problem of the role of central nervous system in controlling hibernation are analyzed. It is shown that limbic structures (septal zone, hippocamp, hypothalamus) are of great significance. Taking into consideration the key role of medial septum as a generator of hippocampal theta-rhythm, the elevated excitability of septal neurones in brain slices obtained from hibernating animals and other experimental data, a conclusion is drawn about the role of medial septal nuclear complex as the forebrain "watch point" in hibernation. The significance of thyrotropin-releasing hormone in controlling the waking/hibernation cycle is discussed.

Body Temperature↗