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Scientists think they’ve discovered the molecular reason that people get grumpy when they’re stressed.

It looks like a particular enzyme is responsible for behavioural problems connected to chronic stress.

When triggered by stress, this enzyme attacks a synaptic regulatory molecule in the brain called nectin-3.

Remember the name.

The researchers at the Brain Mind Institute in France reveal their findings of experiments on rats in the journal Nature Communications.

It was already known that chronic stress causes a massive release of glutamate, a molecule that acts on certain receptors essential for memory.

What these researchers found is that these receptors activated the MMP-9 enzymes which, like scissors, cut the nectin-3 cell adhesion proteins.

“When this happens, nectin-3 becomes unable to perform its role as a modulator of synaptic plasticity (and hence memory),” says Carmen Sandi, the director of the Brain Mind Institute at EPFL (École Polytechnique Federale De Lausanne).

These effects mean you lose your sociability, avoid interaction with peers and have impaired memory or understanding.

An important synaptic mechanism in the effects of chronic stress. It causes the massive release of glutamate which acts on NMDA receptors, essential for synaptic plasticity. These receptors activate MMP-9 enzymes which, like scissors, cut the nectin-3 cell adhesion proteins. This prevents them from playing their regulatory role, making subjects less sociable and causing cognitive impairment. Credit: EPFL (École Polytechnique Federale De Lausanne)

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