Developmental and activity-dependent changes in K+ currents in satellite glial cells in mouse superior cervical ganglion.
Voltage-gated K+ currents were recorded from freshly dissociated satellite glial cells wrapping around ganglion cells in mouse superior cervical ganglion (SCG) by whole-cell recordings of patch clamp techniques. Both inward and outward K+ currents during membrane hyperpolarization and depolarization were observed in these glial cells. The current-voltage relation of these K+ currents became almost linear in cells obtained more than 4 weeks after birth. The magnitude of the density of inward K+ currents, which were elicited during membrane hyperpolarization and were eliminated by external barium, progressively increased during the first month after birth. This developmental increase in the magnitude of inward K+ current density was not affected by decentralization of SCG done by transection of cervical sympathetic trunk (CST) 5 days after birth. In adult mice, the magnitude of the inward K+ current density decreased after chronic conduction blockade of CST by local application of tetrodotoxin. On the other hand, the magnitude of the inward K+ current density increased after daily intraperitoneal injection of reserpine and this increase was abolished by pre-treatment of decentralization of SCG. These results suggested that preganglionic innervation was not prerequisite for developmental increase in the inward K+ currents and preganglionic neuronal activity upregulates the inward K+ currents in adult mice. Neuronal regulation of glial K+ channel expression would assist in K+ clearance from periganglionic space to maintain neuronal activity.
Konishi
T
T
Department of Neurology, Utano National Hospital, Kyoto, Japan.
D015761:4-Aminopyridine / Q000494:pharmacology; D000375:Aging / Q000502:physiology*; D000818:Animals; D001464:Barium / Q000494:pharmacology; D002478:Cells, Cultured; D015640:Ion Channel Gating; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D011803:Quinine / Q000494:pharmacology; D017783:Superior Cervical Ganglion / Q000254:growth & development / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
D015221:Potassium Channels; D001464:Barium; D013779:Tetrodotoxin; D011803:Quinine; D015761:4-Aminopyridine