PT  - JOURNAL ARTICLE
AU  - S. Choisy
AU  - C. Huchet-Cadiou
AU  - C. Léoty
TI  - Sarcoplasmic Reticulum Ca<sup>2+</sup> Release by 4-Chloro-<em>m</em>-Cresol (4-CmC) in Intact and Chemically Skinned Ferret Cardiac Ventricular Fibers
DP  - 1999 Aug 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 578--586
VI  - 290
IP  - 2
4099  - http://jpet.aspetjournals.org/content/290/2/578.short
4100  - http://jpet.aspetjournals.org/content/290/2/578.full
SO  - J Pharmacol Exp Ther1999 Aug 01; 290
AB  - The purpose of this study was to determine whether 4-chloro-m-cresol (4-CmC) could generate caffeine-like responses in ferret cardiac muscle. The concentration dependence of 4-CmC-mediated release of Ca2+ from the sarcoplasmic reticulum was studied in intact cardiac trabeculae and saponin-skinned fibers in which the sarcoplasmic reticulum was loaded with Ca2+. In intact and saponin-skinned preparations isolated from right ventricle, the effect of 4-CmC on sarcoplasmic reticulum Ca2+ content was estimated by analysis of caffeine contracture after application of chlorocresol. In addition, the effects of 4-CmC on maximal Ca2+-activated tension and the Ca2+ sensitivity of myofibrils were analyzed by using Triton-skinned cardiac fibers. The results show that 4-CmC generates a contractile response in saponin-skinned but not intact fibers. The sarcoplasmic reticulum is implicated in the 4-CmC response; more precisely, in Ca2+ release via the ryanodine receptor. Moreover, 4-CmC, like caffeine, has effects on maximal Ca2+-activated tension and the Ca2+ sensitivity of myofibrils. The American Society for Pharmacology and Experimental Therapeutics