Evaluation of Respiratory Pharmacology in the Conscious Rat using Whole Body Bias Flow Plethysmography.

Abstract

The non-invasive measurement of respiratory function in conscious rats is a necessary component of Safety Pharmacology assessment. We routinely measure respiratory rate, tidal volume and peak inspiratory and expiratory flow in the conscious rat using a whole body plethysmograph by determining lung capacity. Thoracic cavity movement is converted by pressure transducers into a digital signal that is recorded and analyzed by BioSystem XA software (Version 2.9). The purpose of this study is to test the measurement of a wide range of possible respiratory values by recording measurements following administration of various compounds known to illicit significant respiratory responses. Morphine Sulfate, an opioid (10 and 20mg/kg, iv; and 100mg/kg, po) and Baclofen, a skeletal muscle relaxant (10, 20, and 30 mg/kg, po) were used as respiratory depressants. Theophylline (10 and 20 mg/kg, iv) was chosen based on its stimulant effects on respiratory parameters. Here we validate the system and test several compounds with known respiratory effects as potential standard controls in future studies.