Activity-induced Ca2+ transients in nerve and glial cells in the leech CNS.
We have measured activity-induced Ca2+ transients in Retzius neurones, neuropile glial cells, and extracellular spaces of isolated ganglia of the leech Hirudo medicinalis using the fluorescent dye fura-2 and Ca(2+)-sensitive microelectrodes. Neuronal activity, induced by electrical side nerve stimulation (20 Hz/1 min), elicited transient rises of intracellular Ca2+ in both neurones and glial cells, which amounted to 24 +/- nM (n = 15) and 17 +/- 14 nM (n = 7), respectively. The extracellular Ca2+ declined by 160 +/- 73 microM (n = 6) during stimulation. Intra- and extracellular Ca2+ transients were reduced by the glutamate/kainate receptor blocker CNQX (6-cyano-7-dinitroquinozaline-2,3-dione; 50 microM). Our results show that neuronal activity evokes Ca2+ signals not only in neurones, but also in glial cells and suggest that these Ca2+ transients are partly mediated via activation of glutamate/kainate receptors.
Rose
C R
CR
Abteilung für Allgemeine Zoologie, Universität Kaiserslautern, Kaiserslautern, Germany.
Lohr
C
C
Deitmer
J W
JW
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002490:Central Nervous System / Q000166:cytology / Q000378:metabolism*; D004558:Electric Stimulation; D005110:Extracellular Space / Q000378:metabolism; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000378:metabolism*; D007865:Leeches / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009457:Neuroglia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D013997:Time Factors
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D002118:Calcium