Electrophysiological evidence for the existence of receptors for endothelin and vasopressin on cultured astrocytes of rat spinal cord and brainstem

Hösli, L.; Hösli, Elisabeth; Lefkovits, Michael; Wagner, Shlomo

doi:10.1016/0304-3940(91)90611-v

Cited by 23 publications

(8 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown here and by others (41,63), the depolarizing agents BaCl 2 and extracellular K ϩ at high concentrations inhibit the glutamate uptake, and this inhibition is characterized by a similar pattern of parallel decreases in both the V max and the K m (41). ET-1 has been reported to evoke cell membrane depolarization in astrocytes (31,32). If the membrane depolarization is strong enough, glutamate transporters may start operating in a reversed manner, releasing glutamate from the astrocytes instead of taking it up (62).…”

Section: Discussionsupporting

confidence: 72%

“…33, 55, and 56). A number of these pathways have been reported to interact with glutamate transporters and could be involved in the observed decrease in the glutamate uptake: 1) ET-1 evokes the release of arachidonic acid (AA) from astrocytes in primary culture (64); this fatty acid is, in turn, a potent inhibitor of the glutamate uptake (3, 68); 2) ET-1 activates PKC (37), and PKC-mediated phosphorylation of GLAST has been shown to inhibit the activity of this transporter (12); and 3) ET-1 depolarizes astrocytic cell membranes (31,32), and the glutamate uptake is sensitive to changes in membrane potential because it is an electrogenic process characterized by an inward movement of one positive charge per glutamate molecule (8).…”

Section: Discussionmentioning

confidence: 99%

“…Glial cells in rat brain in vivo express predominantly the ET B receptor (29). Cultured astrocytes have also been shown to exhibit ET-binding sites (30,32).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Endothelin-1 decreases glutamate uptake in primary cultured rat astrocytes

Leonova

Thorlin

Åberg

et al. 2001

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide that is also known to induce a wide spectrum of biological responses in nonvascular tissue. In this study, we found that ET-1 (100 nM) inhibited the glutamate uptake in cultured astrocytes expressing the glutamate/aspartate transporter (GLAST); astrocytes did not express the glutamate transporter-1 (GLT-1). The V(max) and the K(m) of the glutamate uptake were reduced by 57% and 47%, respectively. Application of the ET(A) and ET(B) receptor antagonists BQ-123 and BQ-788 partly inhibited the ET-1-evoked decrease in the glutamate uptake, whereas the nonspecific ET receptor antagonist bosentan completely inhibited this decrease. Incubation of the cultures with pertussis toxin abolished the effect of ET-1 on the uptake. The ET-1-induced decrease in the glutamate uptake was independent of extracellular free Ca(2+) concentration, whereas the intracellular Ca(2+) antagonists thapsigargin and 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester abolished the effect of ET-1 on the glutamate uptake. Incubation with the protein kinase C (PKC) antagonist staurosporine, but not with the fatty acid-binding protein bovine serum albumin, prevented the ET-1-induced decrease in the glutamate uptake. These results suggest that ET-1 impairs the high-affinity glutamate uptake in cultured astrocytes through a G protein-coupled mechanism, involving PKC and changes in intracellular Ca(2+).

show abstract

Section: Discussionsupporting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Endothelin-1 decreases glutamate uptake in primary cultured rat astrocytes

Leonova

Thorlin

Åberg

et al. 2001

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

show abstract

“…Astrocytes respond to a variety of neurotransmitters receptors with changes in [CA 2+ ] i (Fellin and Carmignoto, 2004). Although not yet observed specifically in SON astrocytes, receptors for VP appear in cortical (Yamazaki et al, 1997) and spinal cord (Hosli et al, 1991; Hosli and Hosli, 1992) astrocytes in culture, and OT receptors are also present in cortical and hypothalamic astrocytes (Di Scala‐Guenot and Strosser, 1992). As in SON neurons (e.g., Lambert et al, 1994), VP or OT receptor activation results in increases in astrocytes [CA 2+ ] i (Di Scala‐Guenot et al, 1994; Zhao and Brinton, 2002), and VP activation has further been shown to alter water flux in the brain (Niermann et al, 2001; Simard and Nedergaard, 2004).…”

Section: Discussionmentioning

confidence: 99%

Immunocytochemical localization of small‐conductance, calcium‐dependent potassium channels in astrocytes of the rat supraoptic nucleus

Armstrong

Rubrum

Teruyama

et al. 2005

J of Comparative Neurology

View full text Add to dashboard Cite

Supraoptic nucleus (SON) neurons possess a prominent afterhyperpolarization (AHP) that contributes to spike patterning. This AHP is probably underlain by a small-conductance, CA2+-dependent, K+ type 3 (SK3) channel. To determine the distribution of SK3 channels within the SON, we used immunocytochemistry in rats and in transgenic mice with a regulatory cassette on the SK3 gene, allowing regulated expression with dietary doxycycline (DOX). In rats and wild-type mice, SK3 immunostaining revealed an intense lacy network surrounding SON neurons, with weak staining in neuronal somata and dendrites. In untreated, conditional SK3 knockout mice, SK3 was overexpressed, but the pericellular pattern in the SON was similar to that of rats. DOX-treated transgenic mice exhibited no SK3 staining in the SON. Double staining for oxytocin or vasopressin neurons revealed weak co-localization with SK3 but strong staining surrounding each neuron type. Electron microscopy showed that SK3-like immunoreactivity was intense between neuronal somata and dendrites, in apparent glial processes, but weak in neurons. This was confirmed by using confocal microscopy and double staining for glial fibrillary acidic protein (GFAP) and SK3: many GFAP-positive processes in the SON, and in the ventral dendritic/glial lamina, were shown to contain SK3-like immunoreactivity. These studies suggest a prominent role of SK3 channels in astrocytes. Given the marked plasticity in glial/neuronal relationships, as well as studies suggesting that astrocytes in the central nervous system can generate prominent CA2+ transients to various stimuli, a CA2+-dependent K+ channel may help SON astrocytes with K+ buffering whenever astrocyte intracellular CA2+ is increased.

show abstract

“…This effect was inhibited by subtype-non specific V1 antagonists, and a V2 agonist had no effect. Astrocytes express AVP receptors (Hosli et al, 1991). AVP-induced receptor activation leads to increases in water permeability and free cytosolic Ca 2ϩ concentration ([Ca 2ϩ ] i ) with similar potency (Table I).…”

Section: Ion and Water Homeostasis In Brain Cells Cerebrocortical Parmentioning

confidence: 98%

Involvement of non-neuronal brain cells in AVP-mediated regulation of water space at the cellular, organ, and whole-body level

2000

View full text Add to dashboard Cite

Electrophysiological evidence for the existence of receptors for endothelin and vasopressin on cultured astrocytes of rat spinal cord and brainstem

Cited by 23 publications

References 31 publications

Endothelin-1 decreases glutamate uptake in primary cultured rat astrocytes

Endothelin-1 decreases glutamate uptake in primary cultured rat astrocytes

Immunocytochemical localization of small‐conductance, calcium‐dependent potassium channels in astrocytes of the rat supraoptic nucleus

Involvement of non-neuronal brain cells in AVP-mediated regulation of water space at the cellular, organ, and whole-body level

Contact Info

Product

Resources

About