Sodium exchange in mouse and rat muscle

• Main Author: Elshafie, Amin Lutfy Mohamed
• Published: Imperial College London 1968
• Subjects: 572
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.623012

The outward movement of sodium was studied in isolated diaphragm muscle of the rat and in a toe muscle (flexor digitorum brevis TV) of the mouse by means of the isotope ²⁴Na. The sodium exchanged in rat diaphragm with a half-time of approximately five minutes, and the fibre sodium was estimated by compartmental analysis. Strophanthin (10-⁴g/m1) slowed the outward movement of sodium in rat diaphragm and caused an increase in the sodium content of the muscle and a decrease in its potassium content. It was found that these effects were reversible and it was therefore possible during the recovery to demonstrate net extrusion of sodium from the diaphragm. Strophanthin also slowed the outward movement of sodium in mouse muscle and increased its sodium content while the potassium content was decreased. Insulin (0.1 unit/ml.) increased the rate of outward movement of sodium in mouse muscle. It was found that the exchange of sodium in diaphragm muscle which had been denervated (8 days) was more rapid, the half-time being 4.1 min. for denervated muscles as compared with 5.4 min. for controls. The experiments were conducted on a factorial design based on a 4.point assay, and these differences are significant (P<0.01).