TAC1 and osteosarcoma: The IP receptor plays an important role in rat dorsal root ganglion (DRG) neuron sensitisation, which is measured by the release of the neurotransmitter substance P. Nakae and colleagues [64] showed that the IP antagonist 2-[4-(1H-indol-4-yloxymethyl)-benzyloxycarbonylamino]-3-phenyl-propionic acid (compound A) inhibits the accumulation of the second messenger cAMP in the rat osteosarcoma cell line and primary cultured rat DRG neurons without affecting other eicosanoid receptors and leads to an iloprost-induced reduction in the release of substance P.