Endogenous brain-derived neurotrophic factor in the nucleus tractus solitarius tonically regulates synaptic and...

Area of Science:

• Neuroscience
• Cardiovascular Physiology

Background:

• Brain-derived neurotrophic factor (BDNF) and its receptor TrkB are abundant in the nucleus tractus solitarius (nTS).
• The precise role of BDNF signaling in the nTS for cardiovascular homeostasis remains largely uncharacterized.

Purpose of the Study:

• To investigate the in vivo and in vitro effects of BDNF within the nTS on cardiovascular function.
• To elucidate the mechanisms by which BDNF modulates synaptic and neuronal activity in the nTS.

Main Methods:

• Microinjections of BDNF and inhibitors into the rat medial nTS (mnTS).
• In vitro electrophysiological recordings in isolated brainstem slices.
• Assessment of cardiovascular parameters (MAP, HR, LSNA) and neuronal activity (EPSCs, APD).

Main Results:

• BDNF administration in the mnTS increased MAP, HR, and LSNA, effects blocked by K252a.
• Endogenous BDNF neutralization or K252a administration decreased these cardiovascular parameters.
• In vitro, BDNF reduced excitatory synaptic transmission and neuronal excitability in nTS neurons, mediated by AMPA receptors.

Conclusions:

• BDNF signaling in the mnTS exerts a tonic influence on cardiovascular regulation.
• This regulation is achieved through the modulation of glutamatergic excitatory transmission and intrinsic neuronal excitability in the nTS.