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  • NMDAR-mediated activation of pannexin1 channels contributes to the detonator properties of hippocampal mossy fiber synapses.

NMDAR-mediated activation of pannexin1 channels contributes to the detonator properties of hippocampal mossy fiber synapses.

iScience (2024-04-29)
Cinthia Rangel-Sandoval, Marisol Soula, Wei-Ping Li, Pablo E Castillo, David L Hunt
ABSTRACT

Pannexins are large-pore ion channels expressed throughout the mammalian brain that participate in various neuropathologies; however, their physiological roles remain obscure. Here, we report that pannexin1 channels (Panx1) can be synaptically activated under physiological recording conditions in rodent acute hippocampal slices. Specifically, NMDA receptor (NMDAR)-mediated responses at the mossy fiber to CA3 pyramidal cell synapse were followed by a slow postsynaptic inward current that could activate CA3 pyramidal cells but was absent in Panx1 knockout mice. Immunoelectron microscopy revealed that Panx1 was localized near the postsynaptic density. Further, Panx1-mediated currents were potentiated by metabotropic receptors and bidirectionally modulated by burst-timing-dependent plasticity of NMDAR-mediated transmission. Lastly, Panx1 channels were preferentially recruited when NMDAR activation enters a supralinear regime, resulting in temporally delayed burst-firing. Thus, Panx1 can contribute to synaptic amplification and broadening the temporal associativity window for co-activated pyramidal cells, thereby supporting the auto-associative functions of the CA3 region.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Guanosine 5′-[β-thio]diphosphate trilithium salt, ≥85% (HPLC), powder
Sigma-Aldrich
Carbamoylcholine chloride, ≥98% (titration), crystalline
Sigma-Aldrich
Adenosine A2A Receptor Agonist I, CGS 21680, Hydrochloride