We have investigated the effects of natriuretic peptides on oscillations in [Ca2+]c (cytosolic free Ca2+ concentration) in two different cell types: freshly isolated rat hepatocytes and the ECV304 cell line. Our data, from both cell types, suggest that natriuretic peptides modulate the frequency of [Ca2+]c oscillations through alterations in plasma membrane Ca2+ fluxes. Here, we review evidence for a role for plasma membrane Ca2+ fluxes in the control of the frequency of [Ca2+]c oscillations. We describe a hypothetical mechanism through which this might be achieved. We propose a physiological role for regulated control of Ca2+ efflux in modulating [Ca2+]c oscillations.
Abbreviations used: ANP, atrial natriuretic peptide; BNP, brain natriuretic peptide; [Ca2+]c/[Ca2+]o, cytosolic free/extracellular Ca2+ concentration respectively; CSR, Ca2+-sensing receptor; InsP3, inositol 1,4,5-trisphosphate; NCX, Na+/Ca2+ exchange; PMCA, plasma membrane Ca2+ ATPase.
Calcium Oscillations and the 5th UK Calcium Signalling Conference, a Biochemical Society Focused Meeting held at University of Liverpool, 1–2 May 2003