SYP and diabetes mellitus: The fraction of glutamatergic markers (vGluT1/2) or GABAergic marker (vGAT) co-localised with synaptophysin (a marker of all nerve terminals) was not modified either by diabetes or caffeine (Fig. 7B), indicating that the relative density of glutamatergic and GABAergic synapses in the hippocampus does not seem to be affected by either diabetes or caffeine.