Original Research Article
5-Hydroxytryptamine activates a barium-sensitive, cAMP-mediated potassium conductance in the leech giant glial cell
Article first published online: 19 OCT 2004
Copyright © 2004 Wiley-Liss, Inc.
Volume 49, Issue 3, pages 309–317, February 2005
How to Cite
Britz, F. C., Hirth, I. C., Schneider, H.-P. and Deitmer, J. W. (2005), 5-Hydroxytryptamine activates a barium-sensitive, cAMP-mediated potassium conductance in the leech giant glial cell. Glia, 49: 309–317. doi: 10.1002/glia.20120
- Issue published online: 20 DEC 2004
- Article first published online: 19 OCT 2004
- Manuscript Accepted: 28 JUN 2004
- Manuscript Received: 30 APR 2004
- Deutsche Forschungsgemeinschaft. Grant Number: De 231/12-4, 18-1
- membrane potential;
- G-protein-coupled receptor;
- Hirudo medicinalis
5-Hydroxytryptamine (5-HT), a neurotransmitter and neuromodulator in the central nervous system of the leech Hirudo medicinalis hyperpolarizes the giant glial cell in the neuropil of segmental ganglia at micromolar concentrations. The 5-HT-evoked glial response (EC50 ≈2.5 μM) is mediated by a non–desensitizing, G-protein-coupled receptor and due to activation of a Ca2+-independent K+ conductance. The adenylyl cyclase inhibitor SQ22,536 blocks the response to 5-HT; in the presence of 1 mM db-cAMP, but not of 1 mM db-cGMP, the glial response is suppressed. The 5-HT-evoked response is reduced by Ba2+ with half-maximal inhibition at 50 μM Ba2+. The results suggest that release of 5-HT from serotonergic neurons, or the maintenance of micromolar levels of extracellular 5-HT in the ganglion, may help to set the glial membrane potential close to the K+ equilibrium potential. © 2004 Wiley-Liss, Inc.