Dataset Information

Activation of oestrogen receptor ? induces a novel form of LTP at hippocampal temporoammonic-CA1 synapses.

ABSTRACT:

Background and purpose

17? estradiol (E2) rapidly regulates excitatory synaptic transmission at the classical Schaffer collateral (SC) input to hippocampal CA1 neurons. However, the impact of E2 on excitatory synaptic transmission at the distinct temporoammonic (TA) input to CA1 neurons and the oestrogen receptors involved is less clear.

Experimental approach

Extracellular recordings were used to monitor excitatory synaptic transmission in hippocampal slices from juvenile male (P11-24) Sprague Dawley rats. Immunocytochemistry combined with confocal microscopy was used to monitor the surface expression of the AMPA receptor (AMPAR) subunit, GluA1 in hippocampal neurons cultured from neonatal (P0-3) rats.

Key results

Here, we show that E2 induces a novel form of LTP at TA-CA1 synapses, an effect mirrored by the ER? agonist, PPT, and blocked by an ER? antagonist. ER?-induced LTP is NMDA receptor (NMDAR)-dependent and involves a postsynaptic expression mechanism that requires PI 3-kinase signalling and synaptic insertion of GluA2-lacking AMPARs. ER?-induced LTP has overlapping expression mechanisms with classical Hebbian LTP, as HFS-induced LTP occluded PPT-induced LTP and vice versa. In addition, activity-dependent LTP was blocked by the ER? antagonist, suggesting that ER? activation is involved in NMDA-LTP at TA-CA1 synapses.

Conclusion and implications

ER? induces a novel form of LTP at juvenile male hippocampal TA-CA1 synapses. As TA-CA1 synapses are implicated in episodic memory processes and are an early target for neurodegeneration, these findings have important implications for the role of oestrogens in CNS health and neurodegenerative disease.

SUBMITTER: Clements L

PROVIDER: S-EPMC7012968 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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