Lecture 23: Respiration 2 Flashcards
What produces active expiration?
activation of RTN / pFRG
What does respiratory rhythm (both inspiratory and expiratory) originate from? Where is it transmitted?
the brainstem and is transmitted to the spinal cord
What sites are involved in the current view of respiratory rhythmogenesis?
pre-Bötzinger complex (inspiration)
postinspiratory complex (PiCo - post-inspiration)
RTN / pFRG (expiration)
What is the respiratory neuronal network made up of?
continuous column of “respiratory neurons” from the pontine tegmentum to the origin of the spinal cord (PRG + VRG)
What is the PRG and the VRG?
the pontine respiratory group and the ventral respiratory group
What is the DRG?
the dorsal respiratory group = NTS
Which regions is the ventral respiratory group subdivided into?
the Bötzinger complex, the pre-Bötzinger complex, the rostral ventral respiratory group and the caudal ventral respiratory group
What are the types of respiratory neurons within the VRG?
I neurons, post-inspiratory neurons, E2 neurons and augmenting expiratory neurons
What are these neurons classified by?
by the respiratory phase the neurons are active in
What is respiratory rhythm generated by?
coordinated activity of respiratory neurons
What type of neurons are BötC neurons?
post-I and aug-E neurons are inhibitory glycinergic
What type of neurons are pre-BötC neurons?
pre-I/I neurons are excitatory glutamatergic and early-I neurons are inhibitory
What type of neurons are rVRG neurons?
aug-I neurons are excitatory to motor output
What is substance P and what receptor does it act on?
a neuropeptide which acts on the metabotropic receptor neurokinin 1 (NK1)
What happens when substance P binds to neurokinin 1?
decreases potassium conductance
What is the effect of decreasing potassium conductance on neuronal membrane potential?
becomes less negative
What is the effect of injecting substance P into the Bötzinger complex?
will increase respiratory time / duration
What is the effect of injecting substance P into the pre-Bötzinger complex?
will increase respiratory frequency
What is the effect of injecting DLH (glutamate receptor agonist) into the Bötzinger complex?
slows breathing
What is the effect of injecting DLH (glutamate receptor agonist) into the pre-Bötzinger complex?
speeds up breathing
What does DLH act on? What does substance P act on?
ionotropic receptors
metabotropic receptors
What is the pontine respiratory group important for?
the post-inspiratory phase
What is BötC important for?
the expiratory phase
What did caudal transection of pre-BötC result in?
abolished respiratory rhythm
What would happen to the three-phase rhythm if GABA was microinjected into the pontine respiratory group?
increase respiratory frequency
Following injection of GABA into the pontine respiratory group, how would expiratory duration change?
would be shortened
With injection of glutamate into the pontine respiratory group, which neuronal subtype would have increased activity?
post-inspiratory
