INVESTIGADORES
ALVAREZ cora Lilia
congresos y reuniones científicas
Título:
Comparative analysis of P receptor-mediated induction of regulatory volume decrease in cells from teleosts and mammals
Autor/es:
ALVAREZ CL, ESPELT MV, PAFUNDO DE, KRUMSCHNABEL G Y SCHWARZBAUM PJ
Lugar:
Innsbruck, Austria
Reunión:
Congreso; 26th Congress of the European Society for Comparative Physiology and Biochemistry; 2009
Institución organizadora:
European Society for Comparative Physiology and Biochemistry
Resumen:
n
most cells hypotonic exposure causes cell swelling followed by ATP
release. The accumulated extracellular ATP (ATPe) may act on P2
receptors to activate a recovery of cell volume known as volume
regulatory decrease (RVD). We have studied the RVD of goldfish
hepatocytes, as compared to trout hepatocytes and a human hepatoma cell
line (HEPG2).
In
hypotonic medium the three cell types undergo swelling followed by a
non-linear accumulation of ATPe. Cells increased their volume about 1.6
times, with subsequent 60% RVD after 40 min (trout and HEPG2 cells) or
no RVD (goldfish). Addition of apyrase (a nucleotide remover) or P2
blockers led to a significant inhibition of RVD in trout cells, but had
no effect in HEPG2. In goldfish hepatocytes extracellular ATPγS (a non-hydrolyzable ATP analogue) induced RVD in a concentration-dependent manner (150 µM, K0.5=570nM),
a response which was abolished by antagonists of P2 receptors. Since
goldfish hepatocytes do release ATP, we decreased the assay medium
several fold to verify if endogenous extracellular ATP could accumulate
in sufficient concentrations to trigger RVD. Accordingly, with a 1:40
V/V dilution of cells (height of the medium 108 µm), goldfish cells had
a 56 % RVD that could be abolished 73% by P2 antagonists.
Thus,
as a preliminary conclusion, although an RVD could be observed in
goldfish, trout and HEPG2 cells, the activation patterns are different.
RVD can be triggered under standard hypotonic conditions (trout and
HEPG2), or when the extracellular medium is sufficiently low to
accumulate ATPe (goldfish). Up to now, the RVD of HEPG2 cells does not
seem to require activation by ATPe.