In:
Canadian Journal of Physiology and Pharmacology, Canadian Science Publishing, Vol. 95, No. 9 ( 2017-09), p. 1058-1063
Abstract:
The application of tetraethylammonium (TEA), a blocker of voltage-dependent potassium channels, can induce long-term potentiation (LTP) in the synaptic systems CA3–CA1 and mossy fiber-CA3 pyramidal cells of the hippocampus. In the mossy fibers, the depolarization evoked by extracellular TEA induces a large amount of glutamate and also of zinc release. It is considered that zinc has a neuromodulatory role at the mossy fiber synapses, which can, at least in part, be due to the activation of presynaptic ATP-dependent potassium (K ATP ) channels. The aim of this work was to study properties of TEA-induced zinc signals, detected at the mossy fiber region, using the permeant form of the zinc indicator Newport Green. The application of TEA caused a depression of those signals that was partially blocked by the K ATP channel inhibitor tolbutamide. After the removal of TEA, the signals usually increased to a level above baseline. These results are in agreement with the idea that intense zinc release during strong synaptic events triggers a negative feedback action. The zinc depression, caused by the LTP-evoking chemical stimulation, turns into potentiation after TEA washout, suggesting the existence of a correspondence between the observed zinc potentiation and TEA-evoked mossy fiber LTP.
Type of Medium:
Online Resource
ISSN:
0008-4212
,
1205-7541
DOI:
10.1139/cjpp-2016-0379
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
2017
detail.hit.zdb_id:
127527-6
detail.hit.zdb_id:
2004356-9