Fig. 2.

Localization of purinergic receptors in glutamatergic synapses in rat hippocampus by immunogold labelling. Electron micrographs of sections single labelled for A₁R (A) and for P2Y₁R (B) are illustrated by examples from CA1 stratum radiatum (A main picture, B inset), CA3 stratum radiatum (A inset) and area dentata (B main picture). Note that both A₁R and P2Y₁R were detected on synaptic and glial membranes; both over the postsynaptic density (black arrows) and over the presynaptic (active zone) membranes at glutamatergic synapses and in glia (*). (C) Omission of primary antibody prevented all gold labelling (picture from CA3 stratum radiatum). Scale bar, 100 nm. m, mitochondria; S, postsynaptic dendritic spine; t, presynaptic axon terminal; *, astroglia. (D and E) Western blot analysis of A₁R (D) and P2Y₁R (E), in rat whole brain and hippocampus membrane homogenates. Rat tissue membranes were lysed, proteins were separated by 10% polyacrylamide SDS-PAGE and probed with the anti-A₁R and anti-P2Y₁R antibodies used for immunocytochemistry.