cGMP measures

Male mdx mice and age-matched wild-type (C57BL10/ScSn) ranging from 6 to 7 weeks of age were ordered from Jackson Laboratories and acclimated for 1 week before the study (N=8 animals per group). Brain tissue measures of cGMP accumulation following drug administration were carried out as previously described.⁵¹ WT (C57BL10/ScSn strain), mdx (C57BL10/ScSn), WT (C57BL/6 J) and mdx^5cv (C57BL/6 J) mice were killed by focused microwave irradiation of the brain. The regions of interest were isolated and homogenized in 0.5 n HCl followed by centrifugation. The supernatant concentrations of cyclic nucleotides were measured using enzyme immunoassay kits (Cayman Chemical, Ann Arbor, MI, USA). The data were analyzed using a two-way analysis of variance followed by Bonferroni correction with the criterion for significance set at P<0.05.