A namesake transporter that links glucose to this substance is found in the luminal membrane of intestinal epithelial cells. The cardiac glycoside ouabain [wah-BAH-in] causes the intracellular concentration of this ion to increase. TTX, or tetrodotoxin [teh-troh-duh-TOK-sin], prevents action potentials by blocking the voltage-gated channels of this ion. Aldosterone acts on the renal distule tubule and collecting duct to increase reabsorption of this ion. A transmembrane 
A namesake transporter that links glucose to this substance is found in the luminal membrane of intestinal epithelial cells. The cardiac glycoside ouabain [wah-BAH-in] causes the intracellular concentration of this ion to increase. TTX, or tetrodotoxin [teh-troh-duh-TOK-sin], prevents action potentials by blocking the voltage-gated channels of this ion. Aldosterone acts on the renal distule tubule and collecting duct to increase reabsorption of this ion. A transmembrane ATPase pumps three ions of it out of the cell and two ions of potassium into the cell. The food additive MSG contains one ion of it. For 10 points, name this ion found with chloride in salt.
A namesake transporter that links glucose to this substance is found in the luminal membrane of intestinal epithelial cells.
sodium [or Na+]