Glucocorticoid-induced endocannabinoid spillover onto GABA synapses following glial retraction is reversed by increasing extracellular viscosity. In slices from normally hydrated rats, dextran (5%) alone had no effect on mIPSC frequency, and did not block the Dex-induced increase in mIPSC frequency. In SON neurons from dehydrated rats, dextran alone (Dextran) had no effect on the mIPSC frequency, but restored the facilitatory effect of dexamethasone on mIPSC frequency (Dextran + Dex) that was lost with dehydration (Dex); *p < 0.05,; **p < 0.01.