Exaggerated Dahl salt-sensitive kidney response to calcium channel agonist isomer of Bay k 8644, but not to calcium channel antagonist isomer of Bay k 8644.

We examined the influence of calcium channel agonist and antagonist optical isomers of BAY-K-8644 on the renal vascular resistance, glomerular filtration rate and sodium excretion of isolated perfused kidneys from Dahl salt-sensitive (DS) and salt-resistance (DR) rats previously stabilized on high- and low-NaCl regimens. The agonist isomer affected these parameters at a lower concentration and to a greater degree in the high-salt DS rat kidneys than in the other three groups. The antagonist isomer also reversed agonist-induced changes to the greatest degree in the high-salt DS rat kidneys. However, the low-salt DS and high-salt DR rat kidneys appeared to be slightly more reactive to these isomers than the low-salt DR rat kidneys, suggesting that hereditary predisposition and dietary NaCl may contribute independently to renal responsiveness to calcium channel-active agents.