Fig. 4.
Localization of PTX-sensitive G-proteins. Gαo and Gαi localized to the membrane of the calyx presynaptic terminal. Calyx terminals are identified by SV2 (red) in the left panel of each pair except in C. A, Monoclonal antibodies (Ab-1 + Ab-2, yellow) localized Go to the membrane of calyx terminals in cryostat sections of whole ciliary ganglia. B, In dissociated preparations, monoclonal anti-Gαo (Ab-2) stained the membranes of presynaptic calyces with especially bright, patchy staining at the synaptic interface. C, Gi was localized by a multistaining approach. Go plus Gi were stained in red with polyclonal anti-Gαo (Northup;red; left panel) whereas Go was stained in green with monoclonal anti-Gαo(Ab-1 plus Ab-2; middle panel). Both labeled the calyx membrane. Superimposing the two stains (right panel) localizes Go by the costained regions (yellow). The distinct regions of red staining (e.g., asterisks) identify membrane regions with Gi but not Go. D,Fully isolated nerve terminals exhibited staining of the surface membrane with polyclonal anti-Gαo (Northup), confirming a presynaptic localization of Go/Gi.