GABAA/benzodiazepine receptors in acutely isolated hippocampal astrocytes

Fraser, Douglas D.; Duffy, Steven; Angelides, Kimon J.; Perez‐Velazquez, Jose L.; Kettenmann, Helmut; MacVicar, Brian A.

doi:10.1523/jneurosci.15-04-02720.1995

Cited by 138 publications

(140 citation statements)

References 70 publications

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“…Immunohistochemistry identified a1 and b1 subunits in these cells [28]. GABA A receptors in Bergmann glial cells were not sensitive to diazepam but to pentobarbital, and immunocytochemistry and immunogold electron microscopy revealed expression of a2, a3, g1 and d [29,30].…”

Section: Abundant Expression Of Gaba a Receptors By Astrocytesmentioning

confidence: 90%

Heterogeneity in expression of functional ionotropic glutamate and GABA receptors in astrocytes across brain regions: insights from the thalamus

Höft

Griemsmann

Seifert

et al. 2014

Phil. Trans. R. Soc. B

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Astrocytes may express ionotropic glutamate and gamma-aminobutyric acid (GABA) receptors, which allow them to sense and to respond to neuronal activity. However, so far the properties of astrocytes have been studied only in a few brain regions. Here, we provide the first detailed receptor analysis of astrocytes in the murine ventrobasal thalamus and compare the properties with those in other regions. To improve voltage-clamp control and avoid indirect effects during drug applications, freshly isolated astrocytes were employed. Two sub-populations of astrocytes were found, expressing or lacking a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. AMPA receptor-bearing astrocytes displayed a lower Kir current density than cells lacking the receptors. In contrast, all cells expressed GABA A receptors. Single-cell RT-PCR was employed to identify the receptor subunits in thalamic astrocytes. Our findings add to the emerging evidence of functional heterogeneity of astrocytes, the impact of which still remains to be defined.

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Section: Abundant Expression Of Gaba a Receptors By Astrocytesmentioning

confidence: 90%

Heterogeneity in expression of functional ionotropic glutamate and GABA receptors in astrocytes across brain regions: insights from the thalamus

Höft

Griemsmann

Seifert

et al. 2014

Phil. Trans. R. Soc. B

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“…While it has been argued that specific culture conditions such as certain types of sera, cocultures with neurons, or treatment with cAMP substantially influence the expression of voltage-gated Ca 2ϩ channels in astrocytes (Barres et al, 1989;Verkhratsky et al, 1998), high-and low-voltage-activated Ca 2ϩ currents have been recorded from immature astrocytes in hippocampal slices (Akopian et al, 1996). In addition, acutely isolated astrocytes from the hippocampus region display Ca 2ϩ influx through verapamil-and Cd 2ϩ -sensitive channels in high extracellular [K ϩ ] (Duffy and MacVicar, 1994) and when depolarized by GABA A receptor activation (Fraser et al, 1995). Thus, it is likely that the results obtained in cultured astrocytes can be extrapolated to what may occur in astrocytes in vivo.…”

Section: Discussionmentioning

confidence: 99%

Expression of voltage‐gated Ca²⁺ channel subtypes in cultured astrocytes

Latour

Hamid

Beedle

et al. 2003

Glia

120

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Transient intracellular [Ca 2ϩ ] increases in astrocytes from influx and/or release from internal stores can release glutamate and thereby modulate synaptic transmission in adjacent neurons. Electrophysiological studies have shown that cultured astrocytes express voltage-dependent Ca 2ϩ channels but their molecular identities have remained unexplored. We therefore performed RT-PCR analysis with primers directed to different voltage-gated Ca 2ϩ channel ␣ 1 subunits. In primary cultures of astrocytes, we detected mRNA transcripts for the, and ␣ 1G (T-type), but not ␣ 1A (P/Q-type), voltage-gated Ca 2ϩ channels. We then used antibodies against all of the Ca 2ϩ channel subunits to confirm protein expression, via Western blots, and localization by means of immunocytochemistry. In Western blot analysis, we observed immunoreactive bands corresponding to the appropriate ␣ 1 subunit proteins. Western blots showed an expression pattern similar to PCR results in that we detected proteins for the ␣ 1B (N-type), ␣ 1C (L-type), ␣ 1D (L-type), ␣ 1E (R-type), and ␣ 1G (T-type), but not ␣ 1A (P/Q-type). Using immunocytochemistry, we observed Ca 2ϩ channel expression for these subunits in punctate clusters on plasmamembrane of GFAP-expressing astrocytes. These results confirm that cultured astrocytes express corresponding proteins to several high-and low-threshold Ca 2ϩ channels but not ␣ 1A (P/Q-type). Overall, our data indicate that astrocytes express multiple types of voltage-gated Ca 2ϩ channels, hinting at a complex regulation of Ca 2ϩ homeostasis in glial cells. GLIA 41:347-353, 2003.

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“…In CCK-secreting neuronal cells, Abucham & Reichlin (1991) showed that GABA hyperpolarized the membrane potential and thereby inhibited CCK release in cortical cells of the brain. Excitatory actions of GABA have, however, already been described in rat lactotrophs (Lorsignol, Taupignon & Dufy, 1994), dendrites of rat hippocampal pyramidal neurons (Anderson, Dingledine, Gjerstad, Langmoen & Mosfeldt Laursen, 1980), nerve endings of rat pituitary (Zhang & Jackson, 1993), and astrocytes (Fraser, Duffy, Angelides, Peres-Velazquez, Kettenmann & MacVicar, 1995). The effect of GABA on the membrane potential depends on the Cl¦ equilibrium potential of a particular cell type.…”

Section: Discussionmentioning

confidence: 99%

Expression of functional GABA_A receptors in cholecystokinin‐secreting gut neuroendocrine murine STC‐1 cells

Glassmeier

Herzig

Höpfner

et al. 1998

The Journal of Physiology

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Gastrointestinal neuroendocrine (NE) cells synthesize, store and secrete γ‐aminobutyric acid (GABA). Recently, an autocrine‐paracrine function of GABA has been proposed for secretion from NE cells. To search for functional GABAA receptors in NE gut cells, we performed whole‐cell and perforated‐patch‐clamp studies in the intestinal cholecystokinin (CCK)‐secreting NE cell line STC‐1. Application of GABA evoked currents in STC‐1 cells. These effects were mimicked by muscimol, an agonist of GABAA receptors, and blocked by picrotoxin or bicuculline, antagonists of GABAA receptors. The GABA‐ or muscimol‐activated currents reversed near 0 mV, which under the recording conditions used was consistent with the activation of the GABAA receptor‐Cl− channel complex. In contrast to the effect on most neurons, GABA as well as muscimol led to a (reversible) depolarization of the membrane potential of STC‐1 cells. Membrane depolarization in turn activated voltage‐gated Ca2+ channels and increased intracellular Ca2+ concentrations in STC‐1 cells. In accordance with the observed membrane depolarization and activation of voltage‐gated Ca2+ channels, both GABA and muscimol stimulated Ca2+‐dependent CCK release. In contrast, bicuculline inhibited the GABA‐induced secretion of CCK. Using the reverse transcription‐polymerase chain reaction (RT‐PCR), mRNA of the GABAA receptor subunits α2, α3, α5, β1, β3 and δ could be detected in STC‐1 cells. In summary, we have shown that the CCK‐secreting gut NE cell line STC‐1 expresses functional GABAA receptors and that GABA stimulates CCK release. Thus, GABA is involved in the fine tuning of CCK secretion from the gut NE cell line STC‐1.

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GABAA/benzodiazepine receptors in acutely isolated hippocampal astrocytes

Cited by 138 publications

References 70 publications

Heterogeneity in expression of functional ionotropic glutamate and GABA receptors in astrocytes across brain regions: insights from the thalamus

Heterogeneity in expression of functional ionotropic glutamate and GABA receptors in astrocytes across brain regions: insights from the thalamus

Expression of voltage‐gated Ca²⁺ channel subtypes in cultured astrocytes

Expression of functional GABA_A receptors in cholecystokinin‐secreting gut neuroendocrine murine STC‐1 cells

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GABAA/benzodiazepine receptors in acutely isolated hippocampal astrocytes

Cited by 138 publications

References 70 publications

Heterogeneity in expression of functional ionotropic glutamate and GABA receptors in astrocytes across brain regions: insights from the thalamus

Heterogeneity in expression of functional ionotropic glutamate and GABA receptors in astrocytes across brain regions: insights from the thalamus

Expression of voltage‐gated Ca2+ channel subtypes in cultured astrocytes

Expression of functional GABAA receptors in cholecystokinin‐secreting gut neuroendocrine murine STC‐1 cells

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Product

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Expression of voltage‐gated Ca²⁺ channel subtypes in cultured astrocytes

Expression of functional GABA_A receptors in cholecystokinin‐secreting gut neuroendocrine murine STC‐1 cells