Seasonal changes in day length induce multisynaptic neurotransmitter switching to regulate hypothalamic network...

Area of Science:

• Neuroscience
• Chronobiology
• Molecular Biology

Background:

• Seasonal changes in day length (photoperiod) influence physiological functions.
• The suprachiasmatic nucleus (SCN)-paraventricular nucleus (PVN) axis is crucial for processing photoperiod information.
• Molecular mechanisms of SCN-PVN network response to photoperiod are not fully understood.

Purpose of the Study:

• To investigate the molecular mechanisms of the SCN-PVN network's response to altered photoperiods.
• To identify specific neuronal populations and molecular players involved in seasonal adaptation.
• To understand how photoperiodic information is translated into behavioral changes.

Main Methods:

• Utilized mouse models to study photoperiod-induced changes.
• Employed in vivo calcium imaging to record neuronal activity.
• Manipulated neuromedin S (NMS) neuron activity to assess functional impact.

Main Results:

• Neuromedin S (NMS) and vasoactive intestinal polypeptide (VIP) neurons in the SCN exhibit photoperiod-dependent neurotransmitter plasticity.
• NMS neurons alter PVN network activity under winter-like photoperiods.
• Chronic NMS neuron manipulation induces neurotransmitter switching in PVN neurons and affects locomotor activity.

Conclusions:

• The SCN-PVN network undergoes molecular adaptations to seasonal photoperiod changes.
• NMS neurons play a key role in mediating these adaptations.
• NMS neurons adjust hypothalamic function to day length via neurotransmitter switching, influencing behavior.