Expression of HA in DRG neurons following i.t. injection of hMOR-T or hMOR plasmids. HA immunostaining in DRG sections isolated from rats injected with saline, hMOR or hMOR-T plasmids. Bright HA immunofluorescence was observed in DRG neurons of both hMOR and hMOR-T injected rat groups. No HA labels were found in neurons of saline injected rats. Scale bars, 50 μm.