Expression of neurotransmitter receptors and Ca2+ channels in the adult fornix and optic nerve.

Using Xenopus oocytes, we have investigated the presence of mRNA coding for neurotransmitter receptors and channels in the adult bovine fornix and optic nerve. Oocytes injected with mRNA from either area, expressed comparable levels of functional receptors to several neurotransmitters, including glutamate and angiotensin II, as well as voltage-activated Ca2+ channels. Glutamate receptors were mainly of the AMPA/kainate type and were expressed in astrocyte cultures from the regions studied, suggesting that the receptors are present at least in this type of glial cells in vivo. These results show that the white matter areas in the adult brain express receptors and channels. These molecules may play an important role in the transfer of information between axons and glial cells.