PT  - JOURNAL ARTICLE
AU  - C L Armour
AU  - L M Diment
AU  - J L Black
TI  - Relationship between smooth muscle volume and contractile response in airway tissue. Isometric versus isotonic measurement.
DP  - 1988 May 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 687--691
VI  - 245
IP  - 2
4099  - http://jpet.aspetjournals.org/content/245/2/687.short
4100  - http://jpet.aspetjournals.org/content/245/2/687.full
SO  - J Pharmacol Exp Ther1988 May 01; 245
AB  - Two different methods of recording contractile response (isometric and isotonic) were used in both spirally cut and intact ring preparations of rabbit airways. The volume of smooth muscle in each airway preparation was compared with the amount of contraction induced by histamine and carbachol. There were significant relationships between smooth muscle volume and carbachol-induced contraction measured isometrically in spiral and ring preparations. There also was a significant relationship between the proportion of airway smooth muscle and the histamine-induced contraction measured isometrically on ring preparations. There were no significant relationships between smooth muscle volume or proportion of airway smooth muscle and the carbachol or histamine contraction measured isotonically. It is concluded that isometric measurements may provide a more accurate representation of smooth muscle changes in response to agonists in vitro. This may indicate that hyper-responsiveness of airway smooth muscle in vitro is more likely to be detected by isometric rather than isotonic measurements.