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Multiple receptors coupled to phospholipase C gate long-term depression in visual cortex
Se-Young Choi1, Jeff Chang, Bin Jiang
1Mind/Brain Institute, Department of Neurosciences, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Summary
Long-term depression (LTD) in the visual cortex requires phospholipase C (PLC) pathway activation. Multiple neurotransmitter systems can independently supply this essential PLC activity, gating visual plasticity.
Area of Science:
- Neuroscience
- Cellular Neuroscience
- Synaptic Plasticity
Background:
- Long-term depression (LTD) is a crucial form of synaptic plasticity in sensory cortices.
- NMDA receptor activation is known to be essential for LTD induction.
Purpose of the Study:
- To investigate the role of phospholipase C (PLC) pathway in the induction of LTD in the visual cortex.
- To identify specific receptors coupled to PLC that are involved in visual cortical LTD.
Main Methods:
- Utilized immunolesions, agonists, and antagonists to manipulate alpha1 adrenergic, M1 muscarinic, and mGluR5 receptors.
- Assessed LTD induction in visual cortical slices and in mice lacking PLCbeta1.
- Intervened with intracellular application of D-myo-inositol-1,4,5-triphosphate (IP3) and PLC or IP3 receptor blockers.
Main Results:
- LTD induction in visual cortex requires PLC pathway activation, in addition to NMDA receptors.
- Simultaneous inactivation of alpha1 adrenergic, M1 muscarinic, and mGluR5 receptors prevented LTD induction.
- LTD was restored by activating any single receptor or by supplying IP3, and impaired by PLC/IP3 blockers or absence of PLCbeta1.
Conclusions:
- Visual cortical LTD necessitates a minimum level of PLC activity, which can be supplied by at least three distinct neurotransmitter systems.
- PLC-linked receptors act as critical gatekeepers for LTD induction.
- This mechanism allows extra-retinal inputs to control visual cortical plasticity in vivo.