Female ICR mice (12-14 weeks age) weighing between 25 and 30 grams were anesthetized with a ketamine/xylazine mixture ( i.p.) allowing the subcutaneous implantation of miniosmotic pumps (Alzet, model 2001). The pumps were filled with verapamil (3.6 mg/kg/day). After treatment animals were anesthetized and weighed. Hearts were excised, rinsed, blotted dry, weighed, and then frozen on dry ice and the stored at -80oC until studied. Animals were anesthetized and euthanized according to animal protocols approved by the University of Kentucky Institutional Animal Care and Use Committee. This investigation conforms with the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication NO. 85-23, revised 1996).
Left ventricular free wall from female mice was rapidly excised and either snap frozen at -80oC or used immediately for RNA isolation. Total RNA was isolated using the RNAqueous -4PCR kit (Ambion) and quantitated spectrophotometrically at 260nm. Contaminating genomic DNA was eliminated by DNase treatment (Ambion). RNA quality was assessed using the Agilent 2100 Bioanalyzer.