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Cats that successfully vent gastric acid‐derived CO 2 exhibit different muscle activation than those that do not (1178.13)
Author(s) -
Held Heather,
Dean Jay,
Lindsey Bruce,
Pitts Teresa,
Rose Melanie,
Mortensen Ashley,
Nicholas Justine,
Baekey David,
Davenport Paul,
Bolser Donald
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.1178.13
Subject(s) - cats , diaphragm (acoustics) , diaphragm muscle , respiratory system , medicine , esophageal sphincter , stomach , anesthesia , chemistry , ventilation (architecture) , breathing , diaphragmatic breathing , respiration , anatomy , pathology , reflux , mechanical engineering , physics , alternative medicine , disease , acoustics , loudspeaker , engineering
We previously reported that inhaling 10% CO2 increased efflux of CO2‐laden gas from cats’ stomachs. Anesthetized cats were surgically instrumented: we measured electromyograms (EMGs) from respiratory and oropharyngeal muscles, including crural diaphragm (CD) and upper esophageal sphincter (UES), as well as tracheal and esophageal gas flow and composition. Animals were exposed to six, 10‐min bouts of 10% CO2 breathing separated by 10 min air breathing. All animals produced gastric CO2 and expelled it during cough, but half failed to expel CO2 during normal breathing (non‐responders (NR) n=4). Responders (Re, n=4) expelled gastric CO2 during normal breathing. EMGs were compared by t‐test to determine if different levels of muscle activation were present in the two groups. EMG signals were rectified and analyzed breath‐by‐breath for inspiratory (ins) and expiratory (exp) values and are presented as mean percent of the highest value observed for that animal ± SE. Compared to Re, NR had higher UES activation during CO2 (15.7±2.1 vs. 21.0±1.9% ins; 15.5±2.1 vs. 19.0±1.1% exp). During air, only ins was different (11.9±1.8 vs. 16.8±1.8%). NR had higher CD activation during ins CO2 (43.9±1.0 vs. 49.4±3.2% ins) but lower activation during exp CO2 (16.5±1.9 vs. 5.7±0.9%) and exp air (15.2±2.0 vs. 5.7±0.9%) breathing. These results show differences in muscle activation between Re and NR, though they suggest that the diaphragmatic portion of the lower esophageal sphincter is less important than suspected. Grant Funding Source : NIH HL89104, HL103415 & ONR