The Ca2+-sensing receptor: a target for polyamines

Studies of human embryonic kidney cells indicated that polyamines are potent agonists for the calcium-sensing receptor (CaR). CaR altered several cellular parameters such as inositol phosphate production, cytosolic free calcium and the activity of a nonselective cation channel. Activation of intracellular calcium transients was produced by spermine. External calcium and spermine both inhibited parathyroid hormone secretion. These results implied the significance of polyamines as effective agonists for the CaR and their role as neurotransmitters or neuromodulators.