Olfactory receptors, Golf alpha and adenylyl cyclase mRNA expressions in the rat heart during ontogenic development

Golf alpha (a G heterotrimeric protein which shares a high homology with Gs a) expression was studied in the rat heart before birth and until weaning. Since Golfa in the neuro-olfactory epithelium is coupled to olfactory recep tors and type III adenylyl cyclase, we looked for the presence of such mole cules in the heart. Golf alpha mRNA was detected in the rat heart, highest levels being found in 21-day old fetuses until 3 days post partum. The prot ein amounts measured by Western blots paralleled the Golf alpha mRNA levels . Immunohistochemical studies revealed the presence of Golf alpha in atrial and ventricular cardiomyocytes. OL1 and latrophilin mRNAs, G protein-coupl ed olfactory receptors, were expressed at early postnatal stages. Adenylyl cyclase mRNAs for type II, type II, type V and type VI were ex-pressed befo re birth and until weaning. Elements for an unexpected signaling pathway in volving odorant receptors like OL1 and latrophilin, Golf alpha and type III adenylyl cyclase were expressed in rat heart, and appeared developmentally regulated. (C) 1999 Academic Press.