The use of hypercapnic conditions to assess opioid-induced respiratory depression in rats.

ABSTRACT:

Introduction

Whole-body plethysmography (WBP) in unrestrained, non-anesthetized rodents is a preclinical method to assess the respiratory depressant effects of opioids, the leading cause of opioid overdose death in humans. However, low baseline respiration rates under normocapnic conditions (i.e., "floor" effect) can render the measurement of respiratory decreases challenging. We assessed hypercapnia-induced increases in respiration as a strategy to assess opioid-induced decreases in respiration in rats.

Methods

WBP was used to assess respiration frequency, tidal volume and minute volume in the presence of normocapnic and hypercapnic (8% CO₂) conditions in rats during the rat diurnal period of the light cycle. The mu-opioid receptor agonist fentanyl was administer

SUBMITTER: Crowley ML 

PROVIDER: S-EPMC8494486 | biostudies-literature | 2021 Sep-Oct

REPOSITORIES: biostudies-literature