PMID- 7524360
OWN - NLM
STAT- MEDLINE
DCOM- 19941118
LR  - 20191210
IS  - 0002-9513 (Print)
IS  - 0002-9513 (Linking)
VI  - 267
IP  - 4 Pt 2
DP  - 1994 Oct
TI  - Renal transepithelial phosphate secretion: luminal membrane voltage and Ca2+ 
      dependence.
PG  - F624-31
AB  - The role of apical membrane electrical potential, the possibility of K+ channel 
      involvement, and the role of extracellular Ca2+ in transepithelial P(i) secretion 
      were examined in primary monolayer cultures of flounder renal proximal tubule 
      cells in Ussing chambers. Exposure to 200 nM thapsigargin (TG) significantly 
      increased net P(i) secretion. In TG-stimulated tissues, substitution of 100 mM 
      KCl for 100 mM NaCl in the luminal medium depolarized the apical membrane 
      potential from -64 +/- 2.8 to -26 +/- 3.9 mV and strongly inhibited net P(i) 
      secretion. In 32P(i)-preloaded tissues, cell-to-lumen exit of 32P(i) was 
      significantly decreased to approximately 50% of control by high luminal K+ while 
      cell-to-peritubular bath movement was unchanged. Addition of BaCl2 (2 mM) or 
      charybdotoxin (20 nM) to the luminal surface significantly reduced TG-stimulated 
      net P(i) secretion. The elevation of bath Ca2+ from 2 to 5 mM significantly 
      increased secretory flux and decreased reabsorptive flux. The effect of TG on net 
      P(i) secretion was reduced by the Ca2+ channel blocker verapamil (VE, 100 microM) 
      to 65% of control and by calmodulin antagonist W-7 (20 microM) to 35% of control 
      but it was not blocked by the protein kinase inhibitor H-7 (100 microM). VE also 
      significantly inhibited the P(i) secretion induced by acidification of the 
      peritubular bathing medium. The data indicate that transepithelial P(i) secretion 
      induced by TG is significantly influenced by apical membrane electrical polarity, 
      which may be regulated in part by Ca(2+)-activated K+ channels.
FAU - Lu, M
AU  - Lu M
AD  - Department of Physiology and Neurobiology, University of Connecticut, Storrs 
      06269-3042.
FAU - Barber, L E
AU  - Barber LE
FAU - Renfro, J L
AU  - Renfro JL
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - Am J Physiol
JT  - The American journal of physiology
JID - 0370511
RN  - 0 (Isoquinolines)
RN  - 0 (Phorbol Esters)
RN  - 0 (Phosphates)
RN  - 0 (Phosphorus Radioisotopes)
RN  - 0 (Piperazines)
RN  - 0 (Scorpion Venoms)
RN  - 0 (Sulfonamides)
RN  - 0 (Terpenes)
RN  - 115422-61-2 (Charybdotoxin)
RN  - 3OWL53L36A (Mannitol)
RN  - 65595-90-6 (W 7)
RN  - 660YQ98I10 (Potassium Chloride)
RN  - 67526-95-8 (Thapsigargin)
RN  - 84477-87-2 (1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine)
RN  - CJ0O37KU29 (Verapamil)
RN  - EC 2.7.11.13 (Protein Kinase C)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
MH  - Animals
MH  - Calcium/*pharmacology
MH  - Calcium-Transporting ATPases/antagonists & inhibitors
MH  - Cell Membrane/drug effects/physiology
MH  - Charybdotoxin
MH  - Electrophysiology/methods
MH  - Epithelium/drug effects/physiology
MH  - Flounder
MH  - In Vitro Techniques
MH  - Isoquinolines/pharmacology
MH  - Kidney/*physiology
MH  - Kinetics
MH  - Mannitol/pharmacology
MH  - Membrane Potentials/drug effects
MH  - Models, Biological
MH  - Phorbol Esters/pharmacology
MH  - Phosphates/*metabolism
MH  - Phosphorus Radioisotopes
MH  - Piperazines/pharmacology
MH  - Potassium Chloride/pharmacology
MH  - Protein Kinase C/antagonists & inhibitors
MH  - Scorpion Venoms/pharmacology
MH  - Sulfonamides/pharmacology
MH  - Terpenes/pharmacology
MH  - Thapsigargin
MH  - Time Factors
MH  - Verapamil/pharmacology
EDAT- 1994/10/01 00:00
MHDA- 1994/10/01 00:01
CRDT- 1994/10/01 00:00
PHST- 1994/10/01 00:00 [pubmed]
PHST- 1994/10/01 00:01 [medline]
PHST- 1994/10/01 00:00 [entrez]
AID - 10.1152/ajprenal.1994.267.4.F624 [doi]
PST - ppublish
SO  - Am J Physiol. 1994 Oct;267(4 Pt 2):F624-31. doi: 
      10.1152/ajprenal.1994.267.4.F624.