A novel NO-dependent ‘molecular-memory-switch’ mediates presynaptic expression and postsynaptic maintenance of LTP in the octopus brain

Ana Luiza Turchetti-Maia, Naama Stern-Mentch, Flavie Bidel, Nir Nesher, Tal Shomrat, & Binyamin Hochner

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Dec 11, 2018
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Received Date: 22nd October 18

The octopus brain shows a robust hippocampal-like activity-dependent LTP, which is NMDA-independent, yet associative and presynaptically expressed and, as shown here, also independent of protein synthesis. Have the molecular mechanisms for mediating this LTP evolved independently or have they converged? Here we report on a distinctive adaptation of the nitric-oxide (NO) system for mediation of the octopus LTP. Unlike the suggested role of NO in LTP induction in the hippocampus, in octopus, inhibitors of NO-synthase (NOS) did not block LTP induction but either 1) reversibly ‘erased’ LTP expression, suggesting that a constitutive elevation in NO mediates the presynaptic LTP expression or 2) ‘reversed’ LTP induction and maintenance because a second LTP could be induced after inhibitor washout. We therefore propose a protein synthesis-independent ‘molecular-switch’, whereby NO-dependent NOS reactivation maintains NOS in its active state. Thus, while the octopus LTP shows marked evolutionary convergence with LTP in vertebrates, an extreme molecular novelty has evolved to mediate it.

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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.


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