In a healthy, vitamin D–replete, elderly population (70–90 y of age), no correlation was found between serum 1,25(OH)D 3 concentration and knee-extension strength, although both declined with age ( 61 ). This finding was the same in the study by Grady et al ( 62 ), in which 98 healthy, mostly vitamin D–replete, volunteers (>69 y of age) showed no significant differences in knee extension or flexion strength after treatment with μg 1,25(OH)D 3 /d or a placebo for 6 mo. Although muscle strength declined by %/y in this population, serum 1,25(OH)D 3 concentrations remained stable with age, increasing only moderately after 6 mo of treatment.
Calcium metabolism appears to underlie neuronal cell death via excitotoxicity,     and hormonally active vitamin D confers a protective effect in vitro at physiologically relevant concentrations up to 100nM but not above.  This mechanism of protection appears to be mediated via a downregulation of L-type voltage-sensitive Ca 2+ ion channels,  an effect which has also been seen in bone cells.   These L-type channels have been implicated in excitotoxicity.  
Eplerenone is an antimineralocorticoid , or an antagonist of the mineralocorticoid receptor (MR).  Eplerenone is also known chemically as 9,11α-epoxy-7α-methoxycarbonyl-3-oxo-17α-pregn-4-ene-21,17-carbolactone and "was derived from spironolactone by the introduction of a 9α,11α-epoxy bridge and by substitution of the 17α-thoacetyl group of spironolactone with a carbomethoxy group".  The drug controls high blood pressure by blocking the binding of aldosterone to the mineralocorticoid receptor (MR) in epithelial tissues, such as the kidney.  Blocking the action of aldosterone decreases blood volume and lowers blood pressure.  It has 10- to 20-fold lower affinity for the MR relative to spironolactone ,  and is less potent in vivo as an antimineralocorticoid.  However, in contrast to spironolactone, eplerenone has little affinity for the androgen , progesterone , and glucocorticoid receptors .   It also has more consistently observed non-genomic antimineralocorticoid effects relative to spironolactone (see membrane mineralocorticoid receptor ).  Eplerenone differs from spironolactone in its extensive metabolism, with a short half-life and inactive metabolites.