Der respiratorische Gaswechsel der winterschlafenden Fledermaus

Hári, Paul

doi:10.1007/bf01677975

Cited by 16 publications

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“…Comparison with other data on bats. Metabolic rates of bats have been determined by several authors, either as oxygen consumption (Almeida et al, 1926;Kayser, 1938Kayser, , 1939Kayser, , 1940Morrison, 1948;Pearson, 1947), or carbon dioxide production (Delseaux, 1887;Koeninck, 1899;Pembrey and White, 1896), or both (Burbank and Young, 1934;Hari, 1909). These have been measured over a small range of temperatures with the exception of the series by Kayser (1940).…”

Section: Discussionmentioning

confidence: 99%

The Metabolic Rates and Body Temperatures of Bats

Hock¹

1951

The Biological Bulletin

243

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Section: Discussionmentioning

confidence: 99%

The Metabolic Rates and Body Temperatures of Bats

Hock¹

1951

The Biological Bulletin

243

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Secretory processes in follicular cells of the bat thyroid. III. The occurrence of extracellular vesicles and colloid droplets during arousal from hibernation

1974

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Ultrastructural changes that occur in follicular cells of the bat thyroid gland just prior to, and immediately after arousal from hibernation are discussed in relation to the known changes which occur in thyroid function during arousal from hibernation. The most distinctive ultrastructural change that takes place just before emergence from hibernation is the occurrence, extracellularly, of concentrations of small vesicles lying in the colloid near the cell's apical plasma membrane. Similar accumulations of vesicles are absent in the apical cytoplasm of the follicular cell. Other principal changes from the early hibernating state found at this time are an increase in the number of apical vacuoles, dense granules and multivesicular bodies. These changes are followed at arousal itself by the appearance of large numbers of intracytoplasmic colloid droplets, often intimately associated with dense granules. An unusual feature of these follicular cells is that although they are rich in colloid droplets, apical pseudopods cannot be found.Numerous studies have demonstrated that the thyroid gland of mammalian hibernators exhibits an endogenous yearly cycle of activity. The thyroid is most active during the spring, when the animals are emerging from hibernation, and least active during the winter when the animals are hibernating (Kayser, '61; Hoffman, '65). In order to correlate these seasonal changes in thyroidal activity with the ultrastructure of the gland, we have periodically examined the fine structure of the bat follicular cells during the animals' yearly life cycle. In preceding papers we have already described the ultrastructural changes which occur in bat follicular cells during the homeothermic (active), preparatory and hibernating phases of the annual life cycle (Nunez and Becker, '70; Nunez, '71). In this study we describe the changes in follicular cells of the bat just prior to, and during arousal from hibernation. MATERIALS AND METHODSAdult bats of the species Myotis lucifzigzis and Pipestrilliis pipestrillus were used. All animals were captured in their natural habitat. Hibernating bats were collected in a cave in mid-April near the end of their period of hibernation. Active bats were caught in a barn in late April and in early June. The hibernating and active bats were of either sex. Hibernating animals were gently placed, in the cave where they were collected, into containers, the bottom halves of which were filled with ice in order to maintain the hibernating state. They were taken to the laboratory and kept in a cold room at 4°C. Three of the hibernating bats were killed by rapid decapitation in the cold room the following morning. The other animals were kept at 4°C in the hibernating state and killed 24, 48 and 96 hours later. Active bats were kept in the laboratory at room temperature and killed the following day. For electron microscopy, thyroid glands were removed in toto, and fixed in ice-cold 6.25% glutaraldehyde in 0.067 M cacodylate buffer, pH 7.3, for 4 hours. Next, the tissues were w...

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Lipid droplet accumulation in cardiac muscle cells of the bat: Potential auto‐toxicity of the cardiac sympathetic innervation

1975

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The previously described ability of reserpine and parachlorophenylalanine to induce the accumulation of lipid droplets in ventricular cardiac muscle cells of the bat was investigated. Lipid droplet accumulation was assessed qualitatively by light microscopy and quantitatively by morphometric analysis of electron micrographs. An hypothesis that the action of the drugs was an indirect one, mediated by the cardiac adrenergic innervation, was framed and tested. Lipid droplet accumulation occurred during a time of intense sympathetic activity, that of arousal from hibernation. The ability of the two drugs to produce the effect was antagonized by prior sympathectomy with 6-hydroxy-dopamine.The effect was mimicked by administration of exogenous norepinephrine together with inhibitors of its catabolic enzymes, monoamine oxidase and catechol-omethyl transferase. These observations are all consistent with the initial hypothesis and raise the possibility that endogenous norepinephrine in the cardiac sympathetic innervation might be, at least potentially, auto-toxic.The accumulation ad lipid droplets in cardiac muscle cells of the bat's cardiac ventricle has been observed in animals treated with the drug reserpine (Hagopian et al., '72). Similar chainges have also been induced in the hearts of active bats by the administration of parachlorophenylalanine (PCPA: Hagopian et al., '73a). Reserpine depIetes tissues of both serotonin and catecholamines (Carlsson, '66, for references) while PCPA, a tryptophan hydroxylase inhibitor, essentially depletes only serotonin (Koe and Weissman, ' 168). In subsequent experiments bats were given 6-hydroxydopamine (6-HD: Hagopian et al., '73b), a drug known to cause depletion of norepinephrine (NE) from tissues by effecting a chemical sympathectomy (Malmfors and Thoenen, '71). 6-HD did deplete the bat's heart of NE and evidence of degeneration of adrenergic axon terminals was obtained. However, no lipid accumulation in cardiac muscle cells was associated with these effects of the drug (Hagopian et al., '73b droplets to accumulate in cardiac muscle cells and, in the previous instance (after PCPA) lipid droplets could be induced to accumulate without an accompanying depletion of catecholamines. Therefore, it seems clear that depletion of catecholamines is not causally related to lipid droplet accumulation in cardiocytes. The action of PCPA and reserpine must be explained in other terms. The effect of PCPA is particularly interesting since the heart contains very little serotonin (Snyder et al., '65). This raises the possibility that lipid droplet accumulation may be an indirect effect of the drugs, resulting from their action on the central nervous system and mediated through the cardiac innervation.The catecholamines, isoproterenol and NE, have been reported to induce a cardiomyopathy associated with lipid accumulation in cardiac muscle cells (Ferrans et al., '64; Regan et al., '72). These observations suggest that adrenergic nerves may provide the common pathway used by the drugs to...

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Der respiratorische Gaswechsel der winterschlafenden Fledermaus

Cited by 16 publications

References 0 publications

The Metabolic Rates and Body Temperatures of Bats

The Metabolic Rates and Body Temperatures of Bats

Secretory processes in follicular cells of the bat thyroid. III. The occurrence of extracellular vesicles and colloid droplets during arousal from hibernation

Lipid droplet accumulation in cardiac muscle cells of the bat: Potential auto‐toxicity of the cardiac sympathetic innervation

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