Increased vascular response to calcium channel agonist by Dahl S rat kidney.

Abstract

We examined responses to the calcium channel agonist, BAY-K 8644, of isolated perfused kidneys from Dahl salt-sensitive (DS) and -resistant (DR) rats that had been stabilized on high (HI) and low (LO) NaCl intakes. Mean arterial pressures of DS/HI rats exceeded those of the other three groups. BAY-K 8644 significantly increased the renal vascular resistance (RVR) of DS/HI and DS/LO kidneys, by 38 and 12%, respectively, but did not increase RVR of DR/HI or DR/LO kidneys significantly (6 and 2%, respectively). Increases in RVR and decreases in glomerular filtration rate of DS/HI kidneys exceeded those of DR/HI kidneys. Increases in the RVR of DS/LO kidneys exceeded those of DR/LO kidneys. Experiments utilizing the separate calcium channel agonist and antagonist enantiomers of BAY-K 8644 corroborated these findings, but at lower concentrations. "Chemical sympathectomy" with 6-hydroxydopamine increased the reactivity of kidneys from only high-NaCl animals to BAY-K 8644 without regard to Dahl S or R status. In conclusion, the DS kidney vasculature manifests an increase in responsiveness to this calcium channel agonist, independently of antecedent NaCl loading or high blood pressure. However, a high antecedent salt intake or hypertension enhances vascular responsiveness of the DS kidney to BAY-K 8644.

• Authors: T H Steele, L Challoner-Hue
• Journal: The American journal of physiology (Am J Physiol) Vol. 254 Issue 4 Pt 2 Pg. F533-9 (Apr 1988) ISSN: 0002-9513 [Print] United States
• PMID: 2451434 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Sodium, Dietary
• 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
• Nitrendipine
• Verapamil

Topics

• 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester (pharmacology)
• Animals
• Blood Pressure (drug effects)
• Glomerular Filtration Rate (drug effects)
• In Vitro Techniques
• Kidney (drug effects, physiology)
• Male
• Nitrendipine (pharmacology)
• Rats
• Rats, Inbred Strains
• Rats, Mutant Strains
• Reference Values
• Renal Circulation (drug effects)
• Sodium, Dietary (pharmacology)
• Species Specificity
• Verapamil (pharmacology)