AVP-fragment peptides induce Ca2+ transients in cells cultured from rat circumventricular organs

Abstract

To investigate receptors for the naturally occurring fragments of [Arg8]vasopressin (AVP), Ca2+ measurements were performed in cells cultured from the subfornical organ (SFO) and the organum vasculosum of the lamina terminalis (OVLT). AVP(4-9) and AVP(4-8) applied in nanomolar concentrations triggered rises in the intracellular Ca2+ concentration in neurons and astrocytes cultured from both circumventricular organs (CVOs) which are located in the lamina terminalis of the rat brain. The determination of the investigated cell type was confirmed by immunocytochemistry with cell type-specific antibodies. The functional data from single cultured cells and receptor autoradiographic studies on tissue slices favour the existence of specific receptors for AVP fragments which are different from those for the parental AVP.