The effect of potassium concentration on Ca45 uptake in frog sartorius muscle

✍ Scribed by Weiss, George B. ;Bianchi, C. P.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1965
• Tongue: English
• Weight: 621 KB
• Volume: 65
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030650312

✦ Synopsis

A.BSTRACT

Radiocalcium uptake by frog sartorius muscle is increased as the potassium concentration of the bathing Ringer is increased from 1.6 mM to 32.0 mM; at higher concentrations of K+ no further increase i n radiocalcium uptake occurs. Substitution of the chloride of Ringer solution by nitrate increases the amount of radiocalcium uptake at potassium concentrations between 1.6 and 32.0 mM but not at higher concentrations. The nitrate anion enhances both the maximum tension and the area of the contracture curves that occur between 16 and 80 mM K+. Comparison of paired muscle preparations i n nitrate Ringer at 32 mM K+ and 80 mM K C shows no difference i n total radiocalcium uptake and no difference i n the area under the contmcture curves. When a three minute prequilibration period i n Ca45 is omitted, the radiocalcium uptake by the sartorius muscle i n 80 mM K+, Ca45 Ringer nitrate is