Respiratory rhythm generation: preBötzinger neuron discharge patterns and persistent sodium current.

Area of Science:

• Neuroscience
• Respiratory Physiology

Background:

• The pontine brainstem (pBc) is hypothesized to contain the central rhythm-generating network for breathing.
• Previous studies suggest a role for pBc neurons in respiratory rhythmogenesis.

Purpose of the Study:

• To investigate the role of pBc neurons in respiratory rhythm generation.
• To examine the properties of neurons within the pBc and adjacent respiratory regions.

Main Methods:

• Recording neuronal activity and phrenic nerve activity.
• Analyzing phase relationships and discharge rates of respiratory neurons.
• Documenting persistent sodium currents in pBc neurons.

Main Results:

• Pre-inspiratory (pre-I) and E-Dec neurons in the pBc maintained consistent phase relationships and peak discharge rates with phrenic nerve activity.
• Other respiratory neuron populations did not maintain these relationships under altered respiratory patterns.
• A substantial persistent sodium current was identified in many pBc neurons.

Conclusions:

• The findings support the role of pBc pre-I and E-Dec neurons in generating the respiratory rhythm.
• The presence of persistent sodium currents in pBc neurons is consistent with their proposed pacemaker function.
• Additional neuronal properties likely interact with persistent sodium currents to define the unique characteristics of pBc pacemaker neurons.