The neurotransmitter dopamine acts through various receptor subtypes that are largely associated with enhancement or inhibition of adenylyl cyclases. These dopamine-sensitive adenylyl cyclases are highly concentrated in the corpus stratum and associated limbic structures of the brain, where their levels exceed by orders of magnitude those in other areas of the brain. Here we use in situ hybridization to show that messenger RNA for three of these adenylyl cyclases is not found in the corpus striatum. We have isolated and expressed a complementary DNA encoding new adenylyl cyclase whose selective concentration in the corpus striatum indicates that it may be responsible for the synaptic actions of dopamine.