Faculty Collaboration Database

Characteristics of breathing rate control mediated by a subregion within the pontine parabrachial complex. J Neurophysiol 2017 Mar 01;117(3):1030-1042

Date

12/16/2016

Pubmed ID

27974449

Pubmed Central ID

PMC5338614

DOI

10.1152/jn.00591.2016

Scopus ID

2-s2.0-85014611292 (requires institutional sign-in at Scopus site)   27 Citations

Abstract

The role of the dorsolateral pons in the control of expiratory duration (Te) and breathing frequency is incompletely understood. A subregion of the pontine parabrachial-Kölliker-Fuse (PB-KF) complex of dogs was identified via microinjections, in which localized pharmacologically induced increases in neuronal activity produced increases in breathing rate while decreases in neuronal activity produced decreases in breathing rate. This subregion is also very sensitive to local and systemic opioids. The purpose of this study was to precisely characterize the relationship between the PB-KF subregion pattern of altered neuronal activity and the control of respiratory phase timing as well as the time course of the phrenic nerve activity/neurogram (PNG). Pulse train electrical stimulation patterns synchronized with the onset of the expiratory (E) and/or phrenic inspiratory (I) phase were delivered via a small concentric bipolar electrode while the PNG was recorded in decerebrate, vagotomized dogs. Step frequency patterns during the E phase produced a marked frequency-dependent decrease in Te, while similar step inputs during the I phase increased inspiratory duration (Ti) by 14 ± 3%. Delayed pulse trains were capable of pacing the breathing rate by terminating the E phase and also of triggering a consistent stereotypical inspiratory PNG pattern, even when evoked during apnea. This property suggests that the I-phase pattern generator functions in a monostable circuit mode with a stable E phase and a transient I phase. Thus the I-pattern generator must contain neurons with nonlinear pacemaker-like properties, which allow the network to rapidly obtain a full on-state followed by relatively slow inactivation. The activated network can be further modulated and supplies excitatory drive to the neurons involved with pattern generation.NEW & NOTEWORTHY A circumscribed subregion of the pontine medial parabrachial nucleus plays a key role in the control of breathing frequency primarily via changes in expiratory duration. Excitation of this subregion triggers the onset of the inspiratory phase, resulting in a stereotypical ramplike phrenic activity pattern independent of time within the expiratory phase. The ability to pace the I-burst rate suggests that the in vivo I-pattern generating network must contain functioning pacemaker neurons.

Author List

Zuperku EJ, Stucke AG, Hopp FA, Stuth EA

Authors

Astrid G. Stucke MD Professor in the Anesthesiology department at Medical College of Wisconsin
Eckehard A. Stuth MD Professor in the Anesthesiology department at Medical College of Wisconsin
Edward J. Zuperku PhD Professor in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Dogs
Electric Stimulation
Excitatory Amino Acid Agonists
Exhalation
Female
Male
Parabrachial Nucleus
Phrenic Nerve
Respiration
Respiratory Rate
alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid