Expression of PGE2 EP3 receptor subtypes in the mouse preoptic region

Inflammatory-induced fever is dependent on prostaglandin E2 (PGE2) binding to its EP3 receptor in the thermoregulatory region of the hypothalamus, but it is not known which EP3 receptor isoform(s) that is/are involved. We identified the EP3 receptor expression in the mouse preoptic region by in situ hybridization and isolated the corresponding area by laser capture microdissection. Real-time RT-PCR analysis of microdissected tissue revealed a predominant expression of the EP3α isoform, but there was also considerable expression of EP3γ, corresponding to approximately 15% of total EP3 receptor expression, whereas EP3β was sparsely expressed. This distribution was not changed by immune challenge induced by peripheral administration of LPS, indicating that EP3 receptor splicing and distribution is not activity dependent. Considering that EP3α and EP3γ are associated with inhibitory and stimulatory G-proteins, respectively, the present data demonstrate that the PGE2 response of the target neurons is intricately regulated.