title: Regulatory volume increase and regulatory volume decrease responses in HL-1 atrial myocytes.
abstract: OBJECTIVE
  we have investigated whether cultured cardiomyocytes of the cell line HL-1 have the ability to perform regulatory volume responses both in hypotonic and hypertonic conditions. Furthermore, we characterized those regulatory responses and studied the effects of bumetanide and DIDS in volume regulation of HL-1 cells.
  
  
  METHODS
  we used a light scattering system to measure the transient volume changes of HL-1 cells when subjected to osmotic challenge.
  
  
  RESULTS
  We found that HL-1 cells correct for their volume excess by undergoing regulatory volume decrease (RVD), and also respond to hypertonic stress with a regulatory volume increase (RVI). Rate of RVD was 0.08 ± 0.04 intensity/min, and rate of RVI was 0.09 ± 0.01 intensity/min. Volume recovery was 83.68 ± 5.73 % for RVD and 92.3 ± 2.3 % for RVI. Bumetanide 50 µM inhibited volume recovery, from 92.3 ± 2.3 % (control) to 24.6 ± 8.8 % and reduced the rate of RVI from 0.070 ± 0.020 intensity/min (control) to 0.010 ± 0.005 intensity/min. 50 µM DIDS reduced volume recovery to 42.93 ± 7.7 % and rate of RVI, to 0.03 ± 0.01 intensity/min.
  
  
  CONCLUSIONS
  these results suggest that bumetanide- and DIDS-sensitive mechanisms are involved in the RVI of HL-1 cells, which points to the involvement of the Na(+)/K(+)/2Cl(-) cotransporter and Cl(-)/bicarbonate exchanger in RVI, respectively.
authors.affiliation: Instituto de Investigaciones Cardiologicas "Profesor Alberto Taquini" (ININCA), Facultad de Medicina, Universidad de Buenos Aires; Buenos Aires, Argentina.
authors.forename: Veronica I
authors.initials: VI
authors.lastname: Cacace
authors.forename: Andres G
authors.initials: AG
authors.lastname: Finkelsteyn
authors.forename: Laura M
authors.initials: LM
authors.lastname: Tasso
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Kusnier
authors.forename: Karina A
authors.initials: KA
authors.lastname: Gomez
authors.forename: Jorge
authors.initials: J
authors.lastname: Fischbarg
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000818:Animals; D002034:Bumetanide / Q000494:pharmacology; D002460:Cell Line; D048429:Cell Size / Q000187:drug effects*; D004232:Diuretics / Q000494:pharmacology; D006982:Hypertonic Solutions / Q000494:pharmacology*; D007038:Hypotonic Solutions / Q000494:pharmacology*; D051379:Mice; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects*; D009995:Osmosis / Q000187:drug effects; D013997:Time Factors
chemical_list: D004232:Diuretics; D006982:Hypertonic Solutions; D007038:Hypotonic Solutions; D002034:Bumetanide; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid