Induced multiple nucleoli, nucleolar margination, and cell size changes in supraoptic neurons during dehydration and rehydration in the rat

Hatton, Glenn I.; Walters, James K.

doi:10.1016/0006-8993(73)90256-4

Cited by 142 publications

(47 citation statements)

References 26 publications

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“…In addition to an increase in optical density, there was a significant increase in the area of SON expressing each of these transcripts (Fig. 2), because of increased cell sizes, as previously reported (29) in salt-loaded rats. Thus expression of specific Na ϩ channel transcripts in MNCs was increased by salt-loading.…”

Section: Figsupporting

confidence: 58%

“…Peak sodium current amplitudes in salt-loaded MNCs were increased from 15.8 Ϯ 1.1 nA to 25.3 Ϯ 2.3 nA, while peak sodium current densities were increased by a smaller fraction (1,206 Ϯ 95 pA͞pF, salt-loaded; 989 Ϯ 70 pA͞pF, controls). This is probably due to the increase in cell size within the SON that occurs in salt-loaded animals (29). The increase in SP20 immunoreactivity within the saltloaded SON, in the context of the relatively small increase in sodium current density (which provides a measure of average sodium channel density over the cell body, assuming a relatively uniform distribution of channels), might be interpreted as suggesting that additional Na ϩ channels may have been added in a nonuniform pattern, clustered close to action potential trigger zones or other critical regions.…”

Section: Discussionmentioning

confidence: 99%

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Molecular and functional remodeling of electrogenic membrane of hypothalamic neurons in response to changes in their input

Tanaka

Cummins

Ishikawa

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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Neurons respond to stimuli by integrating generator and synaptic potentials and generating action potentials. However, whether the underlying electrogenic machinery within neurons itself changes, in response to alterations in input, is not known. To determine whether there are changes in Na ؉ channel expression and function within neurons in response to altered input, we exposed magnocellular neurosecretory cells (MNCs) in the rat supraoptic nucleus to different osmotic milieus by salt-loading and studied Na ؉ channel mRNA and protein, and Na ؉ currents, in these cells. In situ hybridization demonstrated significantly increased mRNA levels for ␣-II, Na6, ␤1 and ␤2 Na ؉ channel subunits, and immunohistochemistr y͞immunoblotting showed increased Na ؉ channel protein after salt-loading. Using patch-clamp recordings to examine the deployment of functional Na ؉ channels in the membranes of MNCs, we observed an increase in the amplitude of the transient Na ؉ current after salt-loading and an even greater increase in amplitude and density of the persistent Na ؉ current evoked at subthreshold potentials by slow ramp depolarizations. These results demonstrate that MNCs respond to salt-loading by selectively synthesizing additional, functional Na ؉ channel subtypes whose deployment in the membrane changes its electrogenic properties. Thus, neurons may respond to changes in their input not only by producing different patterns of electrical activity, but also by remodeling the electrogenic machinery that underlies this activity.The nervous system responds to environmental stimuli with altered patterns of electrical activity that trigger physiological responses and behaviors that tend to protect the organism and͞or help it adapt to its environment. The molecular and cellular mechanisms underlying these altered patterns of neuronal activity are not fully understood. They depend, in part, on the integration of generator potentials and excitatory and inhibitory postsynaptic potentials that impinge on neurons within the circuit under study. Whether the electrogenic machinery responsible for this signal integration within these neurons itself changes, however, in response to environmental changes is not well understood.A model for studying the neuronal response to environmental changes is provided by the magnocellular neurosecretory cells (MNCs) in the supraoptic nucleus (SON), which send axons to the neurohypophysis and fire in bursts so as to release vasopressin in response to increases in plasma osmolality. Vasopressin release is a function of action potential frequency in these cells (1, 2) and firing frequency, in turn, is modulated by osmotic stimuli (3-5). Action potential activity in these cells is Na ϩ dependent and tetrodotoxin (TTX) sensitive, indicating that it is mediated by Na ϩ channels (6-9). While it is known that eight types of Na ϩ channels, encoded by distinct genes, are expressed in neurons (10-17), the identity of the Na ϩ channels in supraoptic MNCs is not known. Moreover, the basic mechanisms that ...

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Section: Figsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Molecular and functional remodeling of electrogenic membrane of hypothalamic neurons in response to changes in their input

Tanaka

Cummins

Ishikawa

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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“…Hatton and Walters [1973] studied the frequency of multiple nucleoli in the SON. They observed only intranuclear bodies larger than 2 um.…”

Section: Discussionmentioning

confidence: 99%

Number, Volume and Size Distribution of Nucleoli in Rat Neurosecretory Cells with Suppressed and Stimulated Secretion

Andersen

1990

Cells Tissues Organs

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The nucleoli in the neurons of the supraoptic nucleus were investigated in the rat. This was performed after the secretion of vasopressin had been suppressed by water load, after the secretion had been stimulated by water deprival and in normal rats which had water ad libitum. The cells with high secretory activity had large single nucleoli. The cells with low secretory activity had less nucleolar volume, and a substantial part of the cells contained two nucleoli.

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“…The dynamics of the cells as a function of its secretory capacity in response to various situations, has been demonstrated repeatedly. The dehydratation and saline intake (Iff and Berkowitz, 1965;Kalino, 1975;Koep et al, 1970), the adaptation to desert life (Hatton and Walters, 1973) and to lactation (Kalino, 1975), and so on, have demonstrated an increase of neuron size (Koep etal., 1970), an increase of RER (Morris and Dyball, 1974), an increase of the nuclear area (Hillarp, 1949;Koep et al, 1970) and an increase and lateralization of the nucleolus (Hatton and Walters, 1973). All of these findings have been interpreted as signs of hyperfunctionality of the neurons especially those related to nucleus, nucleolus and RER, because the increase of the neurosecretory material alone could be interpreted as a consequence of a lack of hormonal release (Hillarp, 1949).…”

Section: Amp Effects On the Morphometry Of The Sonmentioning

confidence: 97%

Morphometric and neurosecretory changes in supraoptic neurons after D-amphetamine treatment

Bentura

Lazcano

Zahonero

et al. 1992

J. Neural Transmission

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Induced multiple nucleoli, nucleolar margination, and cell size changes in supraoptic neurons during dehydration and rehydration in the rat

Cited by 142 publications

References 26 publications

Molecular and functional remodeling of electrogenic membrane of hypothalamic neurons in response to changes in their input

Molecular and functional remodeling of electrogenic membrane of hypothalamic neurons in response to changes in their input

Number, Volume and Size Distribution of Nucleoli in Rat Neurosecretory Cells with Suppressed and Stimulated Secretion

Morphometric and neurosecretory changes in supraoptic neurons after D-amphetamine treatment

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