Potassium-dependent calcium influx in acutely isolated hippocampal astrocytes
Potassium depolarization can increase the intracellular ionized calcium concentration ([Ca 2+] i) of cultured astrocytes, but it is not known if astrocytes that have matured in the intact CNS also exhibit voltage-dependent [Ca 2+] i signalling. To address this issue, fluorometric measurements of [Ca...
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| Veröffentlicht in: | Neuroscience 1994-07, Vol.61 (1), p.51-61 |
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| creator | Duffy, S. MacVicar, B.A. |
| description | Potassium depolarization can increase the intracellular ionized calcium concentration ([Ca
2+]
i) of cultured astrocytes, but it is not known if astrocytes that have matured in the intact CNS also exhibit voltage-dependent [Ca
2+]
i signalling. To address this issue, fluorometric measurements of [Ca
2+]
i were obtained from astrocytes acutely isolated from young adult rat hippocampus. In control artificial cerebrospinal fluid containing 5 mM [K
+]
o, average resting [Ca
2+]
i was 195 nM. Elevation of [K
+]
o to 50 mM caused [Ca
2+]
i to increase 150 nM to 1 μM above resting levels. The threshold [K
+]
o necessary to evoke an elevation in [Ca
2+]
i was 20–25 mM, and the magnitude of the [Ca
2+]
i signal grew progressively with increasing [K
+]
o (up to 50 mM). These [Ca
2+]
i increases were blocked completely by removal of external Ca
2+, and markedly suppressed by the calcium channel blockers verapamil (30 μM and greater) and Co
2+ (1 mM). Neither reversal of Na
+-Ca
2+ exchange, nor Ca
2+-activated Ca
2+ release, nor Ca
2+ influx through stretch-activated channels contributed to the [Ca
2+]
i increase. These results suggest that [K
+]
o-evoked [Ca
2+]
i signals are mediated by influx through voltage-gated calcium channels. In contrast to results from cultured astrocytes and acutely isolated neurons, these [Ca
2+]
i increases were insensitive to dihydropyridine compounds.
We conclude that increases in interstitial [K
+], observed
in situ during several pathological conditions, trigger voltage-dependent [Ca
2+]
i signals in astroglial cells. This may constitute an important form of neuron-to-glial communication. |
| doi_str_mv | 10.1016/0306-4522(94)90059-0 |
| format | Article |
| fullrecord | <record><control><sourceid>proquest_cross</sourceid><recordid>TN_cdi_proquest_miscellaneous_76832305</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><els_id>0306452294900590</els_id><sourcerecordid>76832305</sourcerecordid><originalsourceid>FETCH-LOGICAL-c386t-d9702896896e04641fa479c1e6a1d25c80dc4ca54a2110b4a8c185c04f3df63d3</originalsourceid><addsrcrecordid>eNp9kEtrHDEMgE1ISbfb_oME5hBKe5jWHj9mfAmU0BektIf2bBRZQxzmVdtTuv--3uyyxwqBQPokxMfYpeDvBBfmPZfc1Eo3zRur3lrOta35GduIrpV1q5U6Z5sT8py9SOmRl9BKXrCL1hrbWb1h337MGVIK61h7WmjyNOUKYcDSqcLUD-vfUirANdOwq0KaB8jkq4ewLDPCuMBQQcpxxl2m9JI962FI9OpYt-zXp48_b7_Ud98_f739cFej7EyuvW1501lTkrgySvSgWouCDAjfaOy4R4WgFTRC8HsFHYpOI1e99L2RXm7Z68PdJc6_V0rZjSEhDQNMNK_JtaaTjeS6gOoAYpxTitS7JYYR4s4J7vYW3V6R2ytyVrkni6W1ZVfH--v9SP60dNRW5tfHOaQiq48wYUgnTAneyrYp2M0Bo-LiT6DoEgaakHyIhNn5Ofz_j39S8I48</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>76832305</pqid></control><display><type>article</type><title>Potassium-dependent calcium influx in acutely isolated hippocampal astrocytes</title><source>MEDLINE</source><source>Elsevier ScienceDirect Journals</source><creator>Duffy, S. ; MacVicar, B.A.</creator><creatorcontrib>Duffy, S. ; MacVicar, B.A.</creatorcontrib><description>Potassium depolarization can increase the intracellular ionized calcium concentration ([Ca
2+]
i) of cultured astrocytes, but it is not known if astrocytes that have matured in the intact CNS also exhibit voltage-dependent [Ca
2+]
i signalling. To address this issue, fluorometric measurements of [Ca
2+]
i were obtained from astrocytes acutely isolated from young adult rat hippocampus. In control artificial cerebrospinal fluid containing 5 mM [K
+]
o, average resting [Ca
2+]
i was 195 nM. Elevation of [K
+]
o to 50 mM caused [Ca
2+]
i to increase 150 nM to 1 μM above resting levels. The threshold [K
+]
o necessary to evoke an elevation in [Ca
2+]
i was 20–25 mM, and the magnitude of the [Ca
2+]
i signal grew progressively with increasing [K
+]
o (up to 50 mM). These [Ca
2+]
i increases were blocked completely by removal of external Ca
2+, and markedly suppressed by the calcium channel blockers verapamil (30 μM and greater) and Co
2+ (1 mM). Neither reversal of Na
+-Ca
2+ exchange, nor Ca
2+-activated Ca
2+ release, nor Ca
2+ influx through stretch-activated channels contributed to the [Ca
2+]
i increase. These results suggest that [K
+]
o-evoked [Ca
2+]
i signals are mediated by influx through voltage-gated calcium channels. In contrast to results from cultured astrocytes and acutely isolated neurons, these [Ca
2+]
i increases were insensitive to dihydropyridine compounds.
We conclude that increases in interstitial [K
+], observed
in situ during several pathological conditions, trigger voltage-dependent [Ca
2+]
i signals in astroglial cells. This may constitute an important form of neuron-to-glial communication.</description><identifier>ISSN: 0306-4522</identifier><identifier>EISSN: 1873-7544</identifier><identifier>DOI: 10.1016/0306-4522(94)90059-0</identifier><identifier>PMID: 7969895</identifier><identifier>CODEN: NRSCDN</identifier><language>eng</language><publisher>Oxford: Elsevier Ltd</publisher><subject>1,4-Dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)-phenyl]-3-pyridine car☐ylic acid methyl ester ; [Ca 2+] i ; [K +] o ; ACSF ; Animals ; artificial cerebrospinal fluid ; Astrocytes - metabolism ; BAY K 8644 ; Biological and medical sciences ; Bucladesine - pharmacology ; Calcium - metabolism ; Calcium Channels - metabolism ; Carrier Proteins - metabolism ; Cytophotometry ; dbcAMP ; Dihydropyridines - pharmacology ; DMEM ; Dulbecco's modified Eagle's medium ; EGTA ; ethyleneglycol-bis(B-aminoethyl ether)- N,N,N′,N′-tetra-acetate ; extracellular potassium concentration ; F340/380 ; F405/485 fluorescence emission ratio at 405 or 485 nm ; fluorescence emission ratio from 340 and 380 nm excitation ; Fluorescent Dyes ; Fundamental and applied biological sciences. Psychology ; Fura-2 ; GFAP ; glial fibrillary acid protein ; HEPES ; Hippocampus - cytology ; Hippocampus - metabolism ; In Vitro Techniques ; Indoles ; intracellular ionized calcium concentration ; Isolated neuron and nerve. Neuroglia ; N-2-hydroxyethylpiperazine-N′-2-ethanesulphonic acid ; N6,2′- O-dibutyryladenosine 3′,5′-cyclic monophosphate ; Patch-Clamp Techniques ; photomultiplier tube ; PMT ; Potassium - physiology ; Pyridines - pharmacology ; Rats ; Rats, Sprague-Dawley ; Sodium - metabolism ; Sodium-Calcium Exchanger ; Subcellular Fractions - metabolism ; TEA ; tetraethyl-ammonium ; Vertebrates: nervous system and sense organs</subject><ispartof>Neuroscience, 1994-07, Vol.61 (1), p.51-61</ispartof><rights>1994 IBRO</rights><rights>1994 INIST-CNRS</rights><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c386t-d9702896896e04641fa479c1e6a1d25c80dc4ca54a2110b4a8c185c04f3df63d3</citedby><cites>FETCH-LOGICAL-c386t-d9702896896e04641fa479c1e6a1d25c80dc4ca54a2110b4a8c185c04f3df63d3</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktohtml>$$Uhttps://www.sciencedirect.com/science/article/pii/0306452294900590$$EHTML$$P50$$Gelsevier$$H</linktohtml><link.rule.ids>314,776,780,3537,27901,27902,65306</link.rule.ids><backlink>$$Uhttp://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=4107372$$DView record in Pascal Francis$$Hfree_for_read</backlink><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/7969895$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Duffy, S.</creatorcontrib><creatorcontrib>MacVicar, B.A.</creatorcontrib><title>Potassium-dependent calcium influx in acutely isolated hippocampal astrocytes</title><title>Neuroscience</title><addtitle>Neuroscience</addtitle><description>Potassium depolarization can increase the intracellular ionized calcium concentration ([Ca
2+]
i) of cultured astrocytes, but it is not known if astrocytes that have matured in the intact CNS also exhibit voltage-dependent [Ca
2+]
i signalling. To address this issue, fluorometric measurements of [Ca
2+]
i were obtained from astrocytes acutely isolated from young adult rat hippocampus. In control artificial cerebrospinal fluid containing 5 mM [K
+]
o, average resting [Ca
2+]
i was 195 nM. Elevation of [K
+]
o to 50 mM caused [Ca
2+]
i to increase 150 nM to 1 μM above resting levels. The threshold [K
+]
o necessary to evoke an elevation in [Ca
2+]
i was 20–25 mM, and the magnitude of the [Ca
2+]
i signal grew progressively with increasing [K
+]
o (up to 50 mM). These [Ca
2+]
i increases were blocked completely by removal of external Ca
2+, and markedly suppressed by the calcium channel blockers verapamil (30 μM and greater) and Co
2+ (1 mM). Neither reversal of Na
+-Ca
2+ exchange, nor Ca
2+-activated Ca
2+ release, nor Ca
2+ influx through stretch-activated channels contributed to the [Ca
2+]
i increase. These results suggest that [K
+]
o-evoked [Ca
2+]
i signals are mediated by influx through voltage-gated calcium channels. In contrast to results from cultured astrocytes and acutely isolated neurons, these [Ca
2+]
i increases were insensitive to dihydropyridine compounds.
We conclude that increases in interstitial [K
+], observed
in situ during several pathological conditions, trigger voltage-dependent [Ca
2+]
i signals in astroglial cells. This may constitute an important form of neuron-to-glial communication.</description><subject>1,4-Dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)-phenyl]-3-pyridine car☐ylic acid methyl ester</subject><subject>[Ca 2+] i</subject><subject>[K +] o</subject><subject>ACSF</subject><subject>Animals</subject><subject>artificial cerebrospinal fluid</subject><subject>Astrocytes - metabolism</subject><subject>BAY K 8644</subject><subject>Biological and medical sciences</subject><subject>Bucladesine - pharmacology</subject><subject>Calcium - metabolism</subject><subject>Calcium Channels - metabolism</subject><subject>Carrier Proteins - metabolism</subject><subject>Cytophotometry</subject><subject>dbcAMP</subject><subject>Dihydropyridines - pharmacology</subject><subject>DMEM</subject><subject>Dulbecco's modified Eagle's medium</subject><subject>EGTA</subject><subject>ethyleneglycol-bis(B-aminoethyl ether)- N,N,N′,N′-tetra-acetate</subject><subject>extracellular potassium concentration</subject><subject>F340/380</subject><subject>F405/485 fluorescence emission ratio at 405 or 485 nm</subject><subject>fluorescence emission ratio from 340 and 380 nm excitation</subject><subject>Fluorescent Dyes</subject><subject>Fundamental and applied biological sciences. Psychology</subject><subject>Fura-2</subject><subject>GFAP</subject><subject>glial fibrillary acid protein</subject><subject>HEPES</subject><subject>Hippocampus - cytology</subject><subject>Hippocampus - metabolism</subject><subject>In Vitro Techniques</subject><subject>Indoles</subject><subject>intracellular ionized calcium concentration</subject><subject>Isolated neuron and nerve. Neuroglia</subject><subject>N-2-hydroxyethylpiperazine-N′-2-ethanesulphonic acid</subject><subject>N6,2′- O-dibutyryladenosine 3′,5′-cyclic monophosphate</subject><subject>Patch-Clamp Techniques</subject><subject>photomultiplier tube</subject><subject>PMT</subject><subject>Potassium - physiology</subject><subject>Pyridines - pharmacology</subject><subject>Rats</subject><subject>Rats, Sprague-Dawley</subject><subject>Sodium - metabolism</subject><subject>Sodium-Calcium Exchanger</subject><subject>Subcellular Fractions - metabolism</subject><subject>TEA</subject><subject>tetraethyl-ammonium</subject><subject>Vertebrates: nervous system and sense organs</subject><issn>0306-4522</issn><issn>1873-7544</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>1994</creationdate><recordtype>article</recordtype><sourceid>EIF</sourceid><recordid>eNp9kEtrHDEMgE1ISbfb_oME5hBKe5jWHj9mfAmU0BektIf2bBRZQxzmVdtTuv--3uyyxwqBQPokxMfYpeDvBBfmPZfc1Eo3zRur3lrOta35GduIrpV1q5U6Z5sT8py9SOmRl9BKXrCL1hrbWb1h337MGVIK61h7WmjyNOUKYcDSqcLUD-vfUirANdOwq0KaB8jkq4ewLDPCuMBQQcpxxl2m9JI962FI9OpYt-zXp48_b7_Ud98_f739cFej7EyuvW1501lTkrgySvSgWouCDAjfaOy4R4WgFTRC8HsFHYpOI1e99L2RXm7Z68PdJc6_V0rZjSEhDQNMNK_JtaaTjeS6gOoAYpxTitS7JYYR4s4J7vYW3V6R2ytyVrkni6W1ZVfH--v9SP60dNRW5tfHOaQiq48wYUgnTAneyrYp2M0Bo-LiT6DoEgaakHyIhNn5Ofz_j39S8I48</recordid><startdate>19940701</startdate><enddate>19940701</enddate><creator>Duffy, S.</creator><creator>MacVicar, B.A.</creator><general>Elsevier Ltd</general><general>Elsevier</general><scope>IQODW</scope><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>7X8</scope></search><sort><creationdate>19940701</creationdate><title>Potassium-dependent calcium influx in acutely isolated hippocampal astrocytes</title><author>Duffy, S. ; MacVicar, B.A.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c386t-d9702896896e04641fa479c1e6a1d25c80dc4ca54a2110b4a8c185c04f3df63d3</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>1994</creationdate><topic>1,4-Dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)-phenyl]-3-pyridine car☐ylic acid methyl ester</topic><topic>[Ca 2+] i</topic><topic>[K +] o</topic><topic>ACSF</topic><topic>Animals</topic><topic>artificial cerebrospinal fluid</topic><topic>Astrocytes - metabolism</topic><topic>BAY K 8644</topic><topic>Biological and medical sciences</topic><topic>Bucladesine - pharmacology</topic><topic>Calcium - metabolism</topic><topic>Calcium Channels - metabolism</topic><topic>Carrier Proteins - metabolism</topic><topic>Cytophotometry</topic><topic>dbcAMP</topic><topic>Dihydropyridines - pharmacology</topic><topic>DMEM</topic><topic>Dulbecco's modified Eagle's medium</topic><topic>EGTA</topic><topic>ethyleneglycol-bis(B-aminoethyl ether)- N,N,N′,N′-tetra-acetate</topic><topic>extracellular potassium concentration</topic><topic>F340/380</topic><topic>F405/485 fluorescence emission ratio at 405 or 485 nm</topic><topic>fluorescence emission ratio from 340 and 380 nm excitation</topic><topic>Fluorescent Dyes</topic><topic>Fundamental and applied biological sciences. Psychology</topic><topic>Fura-2</topic><topic>GFAP</topic><topic>glial fibrillary acid protein</topic><topic>HEPES</topic><topic>Hippocampus - cytology</topic><topic>Hippocampus - metabolism</topic><topic>In Vitro Techniques</topic><topic>Indoles</topic><topic>intracellular ionized calcium concentration</topic><topic>Isolated neuron and nerve. Neuroglia</topic><topic>N-2-hydroxyethylpiperazine-N′-2-ethanesulphonic acid</topic><topic>N6,2′- O-dibutyryladenosine 3′,5′-cyclic monophosphate</topic><topic>Patch-Clamp Techniques</topic><topic>photomultiplier tube</topic><topic>PMT</topic><topic>Potassium - physiology</topic><topic>Pyridines - pharmacology</topic><topic>Rats</topic><topic>Rats, Sprague-Dawley</topic><topic>Sodium - metabolism</topic><topic>Sodium-Calcium Exchanger</topic><topic>Subcellular Fractions - metabolism</topic><topic>TEA</topic><topic>tetraethyl-ammonium</topic><topic>Vertebrates: nervous system and sense organs</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Duffy, S.</creatorcontrib><creatorcontrib>MacVicar, B.A.</creatorcontrib><collection>Pascal-Francis</collection><collection>Medline</collection><collection>MEDLINE</collection><collection>MEDLINE (Ovid)</collection><collection>MEDLINE</collection><collection>MEDLINE</collection><collection>PubMed</collection><collection>CrossRef</collection><collection>MEDLINE - Academic</collection><jtitle>Neuroscience</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Duffy, S.</au><au>MacVicar, B.A.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Potassium-dependent calcium influx in acutely isolated hippocampal astrocytes</atitle><jtitle>Neuroscience</jtitle><addtitle>Neuroscience</addtitle><date>1994-07-01</date><risdate>1994</risdate><volume>61</volume><issue>1</issue><spage>51</spage><epage>61</epage><pages>51-61</pages><issn>0306-4522</issn><eissn>1873-7544</eissn><coden>NRSCDN</coden><abstract>Potassium depolarization can increase the intracellular ionized calcium concentration ([Ca
2+]
i) of cultured astrocytes, but it is not known if astrocytes that have matured in the intact CNS also exhibit voltage-dependent [Ca
2+]
i signalling. To address this issue, fluorometric measurements of [Ca
2+]
i were obtained from astrocytes acutely isolated from young adult rat hippocampus. In control artificial cerebrospinal fluid containing 5 mM [K
+]
o, average resting [Ca
2+]
i was 195 nM. Elevation of [K
+]
o to 50 mM caused [Ca
2+]
i to increase 150 nM to 1 μM above resting levels. The threshold [K
+]
o necessary to evoke an elevation in [Ca
2+]
i was 20–25 mM, and the magnitude of the [Ca
2+]
i signal grew progressively with increasing [K
+]
o (up to 50 mM). These [Ca
2+]
i increases were blocked completely by removal of external Ca
2+, and markedly suppressed by the calcium channel blockers verapamil (30 μM and greater) and Co
2+ (1 mM). Neither reversal of Na
+-Ca
2+ exchange, nor Ca
2+-activated Ca
2+ release, nor Ca
2+ influx through stretch-activated channels contributed to the [Ca
2+]
i increase. These results suggest that [K
+]
o-evoked [Ca
2+]
i signals are mediated by influx through voltage-gated calcium channels. In contrast to results from cultured astrocytes and acutely isolated neurons, these [Ca
2+]
i increases were insensitive to dihydropyridine compounds.
We conclude that increases in interstitial [K
+], observed
in situ during several pathological conditions, trigger voltage-dependent [Ca
2+]
i signals in astroglial cells. This may constitute an important form of neuron-to-glial communication.</abstract><cop>Oxford</cop><pub>Elsevier Ltd</pub><pmid>7969895</pmid><doi>10.1016/0306-4522(94)90059-0</doi><tpages>11</tpages></addata></record> |
| fulltext | fulltext |
| identifier | ISSN: 0306-4522 |
| ispartof | Neuroscience, 1994-07, Vol.61 (1), p.51-61 |
| issn | 0306-4522 1873-7544 |
| language | eng |
| recordid | cdi_proquest_miscellaneous_76832305 |
| source | MEDLINE; Elsevier ScienceDirect Journals |
| subjects | 1,4-Dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)-phenyl]-3-pyridine car☐ylic acid methyl ester [Ca 2+] i [K +] o ACSF Animals artificial cerebrospinal fluid Astrocytes - metabolism BAY K 8644 Biological and medical sciences Bucladesine - pharmacology Calcium - metabolism Calcium Channels - metabolism Carrier Proteins - metabolism Cytophotometry dbcAMP Dihydropyridines - pharmacology DMEM Dulbecco's modified Eagle's medium EGTA ethyleneglycol-bis(B-aminoethyl ether)- N,N,N′,N′-tetra-acetate extracellular potassium concentration F340/380 F405/485 fluorescence emission ratio at 405 or 485 nm fluorescence emission ratio from 340 and 380 nm excitation Fluorescent Dyes Fundamental and applied biological sciences. Psychology Fura-2 GFAP glial fibrillary acid protein HEPES Hippocampus - cytology Hippocampus - metabolism In Vitro Techniques Indoles intracellular ionized calcium concentration Isolated neuron and nerve. Neuroglia N-2-hydroxyethylpiperazine-N′-2-ethanesulphonic acid N6,2′- O-dibutyryladenosine 3′,5′-cyclic monophosphate Patch-Clamp Techniques photomultiplier tube PMT Potassium - physiology Pyridines - pharmacology Rats Rats, Sprague-Dawley Sodium - metabolism Sodium-Calcium Exchanger Subcellular Fractions - metabolism TEA tetraethyl-ammonium Vertebrates: nervous system and sense organs |
| title | Potassium-dependent calcium influx in acutely isolated hippocampal astrocytes |
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