AT1A, AT1B, and AT2 angiotensin II receptor subtype gene expression in rat brain.

We localized the gene expression of angiotensin II receptor subtypes (AT1A, AT1B, and AT2) in 2-week-old rat brain by in situ hybridization using subtype specific riboprobes. AT1A receptor mRNA but not AT1B or AT2 receptor mRNA was expressed in the subfornical organ and paraventricular nucleus of the hypothalamus. AT1B as well as AT1A receptor mRNA were found in the cerebral cortex and hippocampus. Conversely, AT2 receptor mRNA, but not AT1A or AT1B, was expressed in the medial geniculate nucleus and inferior olive. Our results indicate that AT1A receptors are involved in the well known central functions of angiotensin II. These results also support the hypothesis of the involvement of AT2 receptors in sensory and motor function.