Fig. 9: Glycopyrrolate treatment elicits neural activity in target brain region and partially restores visual function.

a Schematic diagram illustrating the glycopyrrolate or mexiletine treatment paradigm for optic nerve crush (ONC) and superior colliculus local field potential (LFP) recordings upon optical stimulation of retinal ganglion cells (RGCs). b Representative eye-evoked LFPs from all treatment groups. Red lines indicate the onset of optogenetic stimulation. c We detected minimal eye-evoked LFP from mexiletine-treated mice, as reflected by limited number of regenerating axons in the optic chiasm. In stark contrast, glycopyrrolate treatment markedly increased the maximal eye-evoked LFP by 3.2-fold, when compared with vehicle-treated mice. d Schematic diagram illustrating the pupillary light reflex (PLR) test. Mice were allowed to adapt to dark conditions for 1 h before the PLR test. The relative pupil constriction in percentage was calculated as the percentage change in pupil area between the baseline reading after 1-h dark adaptation and 30 s after the light stimulus at 470 nm. e Glycopyrrolate treatment partially restored the pupil constriction, while vehicle-treated control mice failed to fully constrict the pupil upon light stimulation at 6 weeks after ONC. Pupillary diameters were comparable in the mexiletine-treated and vehicle-treated mice. Mean ± SEM (n = 4 per group in (c), n = 4–6 per group in (e)). *P < 0.05 compared with uninjured eye, ^#P < 0.05 compared with vehicle-treated controls; one-way ANOVA followed by post hoc Bonferroni test. n.s. not significant.