μ-Opioid Receptor Agonist Injections Into the Presumed Pre-Bötzinger Complex and the Surrounding Region of Awake Goats Do Not Alter Eupneic Breathing

Authors

K. L. Krause, Medical College of Wisconsin
Suzanne E. Neumueller, Medical College of Wisconsin
B. D. Marshall, Medical College of Wisconsin
T. Kiner, Medical College of Wisconsin
Joshua M. Bonis, Medical College of Wisconsin
Lawrence Pan, Marquette UniversityFollow
B. Qian, Medical College of Wisconsin
Hubert V. Forster, Medical College of Wisconsin

Document Type

Article

Language

eng

Publication Date

11-2009

Publisher

American Physiological Society

Source Publication

Journal of Applied Physiology

Source ISSN

0021-8987

Original Item ID

DOI: 10.1152/japplphysiol.90548.2008

Abstract

Opioids are clinically important in the alleviation of pain. An undesirable side effect of opioids is depression of breathing. Data from isolated preparations suggest this effect is due to attenuation of discharge activity of neurons in the pre-Bötzinger complex (preBötzC), a medullary area with respiratory rhythmogenic properties. The purpose of this study was to examine how [d-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO), a μ-opioid receptor agonist, affected breathing after injection into the presumed preBötzC of the adult awake goat. We hypothesized that DAMGO would cause breathing to decrease and become irregular when injected into the presumed preBötzC and the surrounding region of the conscious animal. We further hypothesized that ventilatory sensitivity to CO₂ and hypoxia would be blunted after the injection of DAMGO. Microtubules were bilaterally implanted into the presumed preBötzC of 10 adult female goats. After recovery from the surgery, DAMGO (0.5–10 μl, 1 nM–10 μM) was injected into the presumed preBötzC during the awake state. DAMGO had no effect on pulmonary ventilation [inspiratory minute ventilation (V̇i)], respiratory rhythm and pattern, the activation pattern of inspiratory and expiratory muscles, or arterial blood gases during eupneic breathing conditions (P > 0.10). However, DAMGO attenuated (P < 0.05) the evoked increase in breathing frequency when inspired CO₂ was increased, and DAMGO attenuated the V̇i response to reduction of inspired O₂ to 10.8% (P < 0.05). We conclude that our data do not provide support for the concept that in awake mammals opioid depression of breathing is due to a directed action of opioids on preBötzC neurons.

Comments

Accepted version. Journal of Applied Physiology, Vol. 107, No. 5 (November 2009): 1591-1599. DOI. © 2009 The American Physiological Society. Used with permission.

Recommended Citation

Krause, K. L.; Neumueller, Suzanne E.; Marshall, B. D.; Kiner, T.; Bonis, Joshua M.; Pan, Lawrence; Qian, B.; and Forster, Hubert V., "μ-Opioid Receptor Agonist Injections Into the Presumed Pre-Bötzinger Complex and the Surrounding Region of Awake Goats Do Not Alter Eupneic Breathing" (2009). Physical Therapy Faculty Research and Publications. 82.
https://epublications.marquette.edu/phys_therapy_fac/82