1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine, Animals, Calcium, Calcium-Calmodulin-Dependent Protein Kinases, Electrophysiology, Female, Indoles, Isoquinolines, Kidney Cortex, Kidney Tubules, Collecting, Male, Maleimides, Piperazines, Potassium Channel Blockers, Potassium Channels, Protein Kinase C, Rats, Rats, Sprague-Dawley