VGluT3 BNST neurons transmit GABA and restrict feeding without affecting rewarding or aversive processing

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Neuroendocrinology

Background:

• The bed nucleus of the stria terminalis (BNST) plays a role in feeding, reward, aversion, and anxiety.
• Understanding specific neuronal populations within the BNST is crucial for dissecting these complex behaviors.

Purpose of the Study:

• To identify and characterize a unique neuronal population within the BNST defined by vesicular glutamate transporter 3 (VGluT3) expression.
• To investigate the function of these VGluT3 BNST neurons in regulating feeding and anxiety-like behaviors.

Main Methods:

• Utilized immunohistochemistry to localize VGluT3 neurons in the BNST.
• Performed whole-cell patch-clamp electrophysiology to assess neurotransmitter release.
• Employed optogenetics and calcium imaging to study neuronal activity and behavioral responses.
• Assessed feeding behavior and anxiety-like paradigms in rodent models.

Main Results:

• Identified VGluT3 neurons in the anteromedial BNST that co-express vesicular GABA transporter (VGaT).
• These neurons project to the arcuate nucleus (ARC) and paraventricular nucleus (PVN) of the hypothalamus and primarily release GABA.
• Activation of BNST VGluT3 neurons reduced sucrose consumption in fasted animals but did not alter anxiety-like or reward/aversion behaviors.
• VGluT3 BNST neurons showed increased activity during sucrose consumption when sated.

Conclusions:

• VGluT3 BNST neurons form a distinct inhibitory pathway to hypothalamic feeding centers.
• This pathway specifically suppresses feeding behavior without influencing anxiety or reward processing.
• These findings offer insights into the neural circuitry controlling appetite and energy homeostasis.