Glial cells isolated from dorsal root ganglia express prostaglandin E2 (EP4) and prostacyclin (IP) receptors

Isolated cells from adult rat dorsal root ganglia (DRG) are frequently used as a model system to study responses of primary sensory neurons to nociceptor sensitizing agents such as prostaglandin E2 and prostacyclin, which are presumed to act only on the neurons in typical mixed cell cultures. In the present study, we evaluated the expression of prostaglandin E2 (EP4) and prostacyclin (IP) receptors in cultures of mixed DRG cells and in purified DRG glia. We show here that EP4 and IP receptor agonists stimulated adenylyl cyclase activity in both mixed DRG cells and in purified DRG glia, and that these responses were specifically inhibited by EP4 and IP receptor antagonists, respectively. The presence of EP4 and IP receptors in DRG glia was further confirmed by the expression of EP4 and IP receptor immunoreactivity and mRNA. With the increasing awareness of neuron-glial interactions within intact DRG and the use of isolated DRG cells in the study of mechanisms underlying nociception, it will be essential to consider the role played by EP4 and IP receptor-expressing glial cells when evaluating prostanoid-induced sensitization of DRG neurons.