title: Role of Ca channel in the renal autoregulatory vascular response analysed by the use of BAY K 8644.
abstract: The role of Ca channel and extracellular Ca2+ on autoregulation of renal blood flow was investigated in the perfused kidney of the anesthetized dog. The perfusion pressure was changed in the range between 60 and 200 mm Hg. Intra-arterial infusion of nifedipine (5 micrograms/min) increased renal blood flow at a perfusion pressure above 100 mm Hg and inhibited autoregulation. Simultaneous infusion of 5 micrograms/min of BAY K 8644 antagonized the effect of nifedipine. Renal blood flow was increased and autoregulatory relationship between flow and perfusion pressure was inhibited by EDTA (30 mg/min) infusion. The inhibitory effect of EDTA on renal autoregulation was counteracted by simultaneous infusion of CaCl2 at 30 mg/min, but not counteracted by that of BAY K 8644 (5 micrograms/min). BAY K 8644 also could not antagonize the inhibitory effect of a vasodilator, papaverine (5 mg/min) on renal blood flow autoregulation. These results provide the evidence that the renal autoregulation involves the process of Ca2+ influx into the vascular smooth muscle cell through the Ca channels.
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000097:blood; D004285:Dogs; D004492:Edetic Acid / Q000494:pharmacology; D005260:Female; D007473:Ion Channels / Q000502:physiology*; D008297:Male; D009543:Nifedipine / Q000494:pharmacology; D010208:Papaverine / Q000494:pharmacology; D012079:Renal Circulation / Q000187:drug effects*
chemical_list: D007473:Ion Channels; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D004492:Edetic Acid; D010208:Papaverine; D009543:Nifedipine; D002118:Calcium