In quinoa, class-1 HKT proteins load this element into bladder cells. Variations in hydrogen concentration in the brain cause acid-sensing pH sensor proteins to mainly transport this element. Paralytic shellfish poisoning occurs when alkaloids like saxitoxin block the transport of this element. (10[1]-5[2])A symporter of glucose and this element (-5[1])called SGLT2 (10[1])is found in proximal tubules. Subunits of proteins that conduct this element contain six transmembrane passes and are voltage-gated. An ion of this element enters neurons during action potential firing. (10[1]-5[3])Blockers for this element’s channels can be used to treat (10[1])arrhythmia. Hydrolysis of ATP pumps three atoms of this element out of cells against (-5[1])potassium. (10[1])For 10 points, (10[1])name this element found alongside chloride in table salt. (10[1])■END■ (10[4])