CELL VOLUME REGULATION MEDIATED BY P RECEPTORS

SCHWARZBAUM, PJ

Conferencia; XXV Reunião Anual Federação de Sociedades de Biologia Experimental (FeSBE); 2010

FESBE

In almost all vertebrate cells challenged by hypotonicity, swelling is followed by a regulatory volume decrease (RVD) that tends to recover the original isotonic cell volume. There is abundant information regarding the intracellular mechanisms mediating volume regulation, but relatively little on extracellular signaling events. Moreover, although several reports show that specific P receptors and ectonucleotidases are important for RVD, the issue has not been studied systematically. To understand nucleotide dependent RVD it is essential to analyse to what extent nucleotides and adenosine accumulate in the extracellular space (nucleotide transmembrane transport), how they are interconverted by ectonucleotidases (nucleotide extracellular metabolism), and activate different purine and pyrimidine receptors (P receptor signaling). Using goldfish hepatocytes challenged by hipotonicity as a cell model to study volume regulation, results will be presented showing how the interaction between extracellular ATP (and other nucleotides), P receptors and ectonucleotidases can modulate RVD. Moreover, since in goldfish hepatocytes RVD is a function of extracellular [ATP], and on the other hand hypotonic exposure leads to a non linear extracellular accumulation of the nucleotide, studying the factors governing the kinetic of extracellular [ATP] is important to characterize the nucleotide-dependent RVD response.