PMID- 8304427
OWN - NLM
STAT- MEDLINE
DCOM- 19940310
LR  - 20191210
IS  - 0002-9513 (Print)
IS  - 0002-9513 (Linking)
VI  - 266
IP  - 1 Pt 1
DP  - 1994 Jan
TI  - Increased intracellular Na+ augments mobilization of Ca2+ from SR in vascular 
      smooth muscle cells.
PG  - C311-7
AB  - The effect of a rise in intracellular Na+ concentration ([Na+]cyt) on the amount 
      of Ca2+ in intracellular stores was studied in vascular smooth muscle cells from 
      the A7r5 line. The relative amount of stored Ca2+ was estimated in fura 2-loaded 
      cells by the rise in cytosolic free Ca2+ concentration ([Ca2+]cyt) evoked by Ca2+ 
      release from the sarcoplasmic reticulum (SR). To improve the detection of 
      released Ca2+, extrusion of Ca2+ from the cytosol was minimized by using 
      nominally Na+/Ca(2+)-free medium containing 0.5 mM La3+ [for vasoconstrictor 
      experiments, the medium contained 0.5 mM ethylene glycol-bis(beta-aminoethyl 
      ether)-N,N,N',N'-tetraacetic acid and no La3+]. Ca2+ release was triggered by 
      thapsigargin (TG), an SR Ca(2+)-ATPase inhibitor, and by the vasoconstrictors 
      arginine vasopressin (AVP) and serotonin (5-HT). Incubation with 1-3 mM ouabain 
      for 20 min, which raises [Na+]cyt from 4.4 to 9.0 mM, increased "resting" 
      [Ca2+]cyt only slightly (from 87 to 122 nM). However, ouabain greatly augmented 
      the release of Ca2+ evoked by TG [from 639 nM (control) to 1,021 nM], by AVP 
      (from 993 to 1,597 nM), and by 5-HT (from 559 to 1,486 nM). Ouabain-induced 
      augmentation of TG-evoked Ca2+ release was not affected by 10 microM verapamil; 
      this implies that the effect of ouabain was not due to Ca2+ entry through 
      voltage-gated Ca2+ channels. The response to TG was not augmented when ouabain 
      was applied for 20 min in Na(+)-free medium (Na+ replaced by equimolar 
      N-methyl-D-glucamine) to prevent [Na+]cyt from rising.(ABSTRACT TRUNCATED AT 250 
      WORDS)
FAU - Borin, M L
AU  - Borin ML
AD  - Department of Physiology, School of Medicine, University of Maryland, Baltimore 
      21201.
FAU - Tribe, R M
AU  - Tribe RM
FAU - Blaustein, M P
AU  - Blaustein MP
LA  - eng
GR  - HL-45215/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Am J Physiol
JT  - The American journal of physiology
JID - 0370511
RN  - 0 (Terpenes)
RN  - 5ACL011P69 (Ouabain)
RN  - 67526-95-8 (Thapsigargin)
RN  - 9NEZ333N27 (Sodium)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Biological Transport
MH  - Calcium/*metabolism
MH  - Calcium-Transporting ATPases/antagonists & inhibitors
MH  - Cell Line
MH  - Intracellular Membranes/*metabolism
MH  - Muscle, Smooth, Vascular/cytology/*metabolism
MH  - Ouabain/pharmacology
MH  - Rats
MH  - Sarcoplasmic Reticulum/*metabolism
MH  - Sodium/*metabolism
MH  - Terpenes/pharmacology
MH  - Thapsigargin
EDAT- 1994/01/01 00:00
MHDA- 1994/01/01 00:01
CRDT- 1994/01/01 00:00
PHST- 1994/01/01 00:00 [pubmed]
PHST- 1994/01/01 00:01 [medline]
PHST- 1994/01/01 00:00 [entrez]
AID - 10.1152/ajpcell.1994.266.1.C311 [doi]
PST - ppublish
SO  - Am J Physiol. 1994 Jan;266(1 Pt 1):C311-7. doi: 10.1152/ajpcell.1994.266.1.C311.