Messenger RNA from Rat Brain Induces Noradrenaline and Dopamine Receptors in Xenopus oocytes

Xenopus oocytes were induced to acquire sensitivity to noradrenaline and dopamine, by injecting them with poly(A)⁺ mRNA isolated from rat brain. In mRNA-injected oocytes, both neurotransmitters elicited a smooth inward membrane current on which was superimposed an oscillatory inward current, which was carried mainly by chloride ions. This contrasts with the native responses that are sometimes seen in non-injected oocytes, where noradrenaline and dopamine both elicit smooth outward currents that are carried mainly by potassium ions. The serotonin antagonist methysergide blocked the induced responses to both noradrenaline and dopamine, and the noradrenaline response was blocked by propranolol.