Brainstem opioid peptidergic neurons regulate cough reflexes in mice

Area of Science:

• Neuroscience
• Respiratory Physiology

Background:

• The brain mechanisms of the cough reflex are not well understood.
• Sensory pathways initiating cough are extensively studied, but central processing remains unclear.

Purpose of the Study:

• To investigate the central neural circuits controlling the cough reflex.
• To identify key neuronal populations involved in initiating cough-like reflexes in mice.

Main Methods:

• Developed a quantitative paradigm for measuring cough-like reflexes in mice.
• Utilized genetic targeting to identify and manipulate specific neuronal populations (Pdyn+ neurons).
• Investigated neural pathways using neuroanatomical and functional tracing techniques.

Main Results:

• Prodynorphin-expressing (Pdyn+) neurons in the nucleus of the solitary tract (NTS) are crucial for capsaicin-induced cough-like reflexes.
• Pdyn+ NTS neurons receive input from Trpv1+ vagal sensory neurons.
• Activation of Pdyn+ NTS neurons elicits cough-like respiratory responses.
• A glutamatergic pathway from Pdyn+ NTS neurons to the caudal ventral respiratory group (cVRG) is essential for cough reflex initiation.

Conclusions:

• Pdyn+ NTS neurons act as a critical initiator of cough-like reflexes.
• This study elucidates a key neuronal pathway in the brainstem responsible for cough reflex control.