Functional properties of neurotransmitter receptors transplanted into Xenopus oocytes

When oocytes of African frog Xenopus laevis were injected with mRNA isolated from rat brains, the oocyted synthesized functional properties such as ionic channels or neurotransmitter receptors based on the injected mRNA. Functional properties of neurotransmitter receptors thus transplanted from rat brains were studied in the oocytes. Analyses of intracellular reaction mechanisms of these receptors revealed that, in this system, receptors that activate G-proteins and stimulate inositol phospholipid metabolism and intracellular Ca²⁺ mobilization were expressed very efficiently. Muscarinic acetylcholine receptor is a typical one of this category. Neurotensin receptor was also found to belong to this category. In addition, a new subtype pf glutamate receptor was found that stimulates the same intracellular reactions. This is the first direct evidence for a glutamate receptor subtype that stimulates G-protein-mediated reactions.