Sodium and water transport in cortical collecting duct of Dahl salt-resistant rat.
Studies were conducted to determine whether the cortical collecting duct (CCD) of the Dahl salt-resistant rat (inbred Rapp strain; R/Jr) exhibits the same responses to deoxycorticosterone (DOC; 2.5 mg as a depot injection in vivo, 3-8 days before experimentation) and arginine vasopressin (AVP, 220 pM in vitro) as the Sprague-Dawley (SD) [L. Chen, S.K. Williams, and J.A. Schafer. Am. J. Physiol. 259 (Renal Fluid Electrolyte Physiol. 28): F147-F156, 1990] and Dahl salt-sensitive (inbred Rapp strain, S/Jr) [C.T. Hawk and J.A. Schafer. Am. J. Physiol. 260 (Renal Fluid Electrolyte Physiol. 29): F471-F478, 1991] CCD. Qualitatively, the R/Jr CCD responded as in the other two strains: AVP elevated the osmotic water permeability (Pf, micron/s) from 0 to approximately 1,200; either AVP or DOC, when used alone, increased the lumen-to-bath 22Na+ flux (Jl-->b, pmol.min-1.mm-1) from the control range of 20-25 to approximately 40 and hyperpolarized the transepithelial voltage. AVP and DOC effects were synergistic, elevating Jl-->b to 90 +/- 5 (mean +/- SE) with both hormones, but this value was significantly lower than observed previously in both the SD and the S/Jr CCD, 125 +/- 6 and 140 +/- 6, respectively. However, bath-to-lumen fluxes (Jb--l) were also significantly lower than observed in the SD and S/Jr CCD. Because net fluxes (Jnet) in these experiments can be determined only as nonpaired differences between unidirectional fluxes, it is uncertain whether Jnet values in the R/Jr CCD are significantly lower than in the SD or S/Jr CCD.(ABSTRACT TRUNCATED AT 250 WORDS)
Kudo
L H
LH
Department of Physiology and Biophysics, University of Alabama at Birmingham 35294.
Hawk
C T
CT
Schafer
J A
JA
D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D001834:Body Water / Q000378:metabolism*; D003900:Desoxycorticosterone / Q000494:pharmacology*; D004351:Drug Resistance; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D006852:Hydrochlorothiazide / Q000494:pharmacology; D007672:Kidney Cortex / Q000187:drug effects / Q000502:physiology*; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012964:Sodium / Q000378:metabolism*; D012982:Sodium, Dietary
D012982:Sodium, Dietary; C013407:benzamil; D006852:Hydrochlorothiazide; D001127:Arginine Vasopressin; D003900:Desoxycorticosterone; D000584:Amiloride; D012964:Sodium