Journal Article

Substance P induces plasticity and synaptic tagging/capture in rat hippocampal area CA2

Baby, Nimmi, Wong, Yuk Peng, Soong, Tuck Wah, Krishna, Kumar, Sajikumar, Sreedharan, Hakim, Muhammad, Dasgupta, Ananya, Behnisch, Thomas

2017

Overview

The hippocampal area Cornu Ammonis (CA) CA2 is important for social interaction and is innervated by Substance P (SP)-expressing supramammillary (SuM) nucleus neurons. SP exerts neuromodulatory effects on pain processing and central synaptic transmission. Here we provide evidence that SP can induce a slowly developing NMDA receptor- and protein synthesis-dependent potentiation of synaptic transmission that can be induced not only at entorhinal cortical (EC)-CA2 synapses but also at long-term potentiation (LTP)-resistant Schaffer collateral (SC)-CA2 synapses. In addition, SP-induced potentiation of SC-CA2 synapses transforms a short-term potentiation of EC-CA2 synaptic transmission into LTP, consistent with the synaptic tagging and capture hypothesis. Interestingly, this SP-induced potentiation and associative interaction between the EC and SC inputs of CA2 neurons is independent of the GABAergic system. In addition, CaMKIV and PKMζ play a critical role in the SP-induced effects on SC-CA2 and EC-CA2 synapses. Thus, afferents from SuM neurons are ideally situated to prime CA2 synapses for the formation of long-lasting plasticity and associativity.

• Publisher: National Academy of Sciences
• Subject: Biological Sciences / Ca2+/calmodulin-dependent protein kinase IV / Cortex / Glutamic acid receptors (ionotropic) / Hippocampal plasticity / Hippocampus / Long-term potentiation / Marking / N-Methyl-D-aspartic acid receptors / Neuromodulation / Neurons / Neuroscience / Pain / Plastic properties / Plasticity / PNAS Plus / Protein biosynthesis / Protein synthesis / Short-term potentiation / Social behavior / Social interaction / Substance P / Synapses / Synaptic plasticity / Synaptic transmission / Synaptogenesis / γ-Aminobutyric acid