Referenced in: none

Automatically associated channels: TRP , TRPC , TRPC1 , TRPC4

Title: Heteromeric canonical transient receptor potential 1 and 4 channels play a critical role in epileptiform burst firing and seizure-induced neurodegeneration.

Authors: Kevin D Phelan, Matthew M Mock, Oliver Kretz, U Thaung Shwe, Maxim Kozhemyakin, L John Greenfield, Alexander Dietrich, Lutz Birnbaumer, Marc Freichel, Veit Flockerzi, Fang Zheng

Journal, date & volume: Mol. Pharmacol., 2012 Mar , 81, 384-92

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22144671

Abstract
Canonical transient receptor potential channels (TRPCs) are receptor-operated cation channels that are activated in response to phospholipase C signaling. Although TRPC1 is ubiquitously expressed in the brain, TRPC4 expression is the most restrictive, with the highest expression level limited to the lateral septum. The subunit composition of neuronal TRPC channels remains uncertain because of conflicting data from recombinant expression systems. Here we report that the large depolarizing plateau potential that underlies the epileptiform burst firing induced by metabotropic glutamate receptor agonists in lateral septal neurons was completely abolished in TRPC1/4 double-knockout mice, and was abolished in 74% of lateral septal neurons in TRPC1 knockout mice. Furthermore, neuronal cell death in the lateral septum and the cornu ammonis 1 region of hippocampus after pilocarpine-induced severe seizures was significantly ameliorated in TRPC1/4 double-knockout mice. Our data suggest that both TRPC1 and TRPC4 are essential for an intrinsic membrane conductance mediating the plateau potential in lateral septal neurons, possibly as heteromeric channels. Moreover, excitotoxic neuronal cell death, an underlying process for many neurological diseases, is not mediated merely by ionotropic glutamate receptors but also by heteromeric TRPC channels activated by metabotropic glutamate receptors. TRPC channels could be an unsuspected but critical molecular target for clinical intervention for excitotoxicity.