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Duric, V.

Publications and source records attributed to Duric, V..

2 recordsLinked to original sources

Prefrontal Cortex Astroglia Modulate Anhedonia-like Behavior

Reductions of astroglia expressing glial fibrillary acidic protein (GFAP) are consistently found in the prefrontal cortex (PFC) of patients with depression and in rodent chronic stress models. Here, we examine the consequences of PFC GFAP+ cell depletion and cell activity enhancement on depressive-like behaviors in rodents. Using viral expression of diphtheria toxin receptor in PFC GFAP+ cells, which allows experimental depletion of these cells following diphtheria toxin administration, we demonstrated that PFC GFAP+ cell depletion induced anhedonia-like behavior within 2 days and lasting up to 8 days, but no anxiety-like deficits. Conversely, activating PFC GFAP+ cell activity for 3 weeks using designer receptor exclusively activated by designer drugs (DREADDs) reversed chronic restraint stress-induced anhedonia-like deficits, but not anxiety-like deficits. Our results highlight a critical role of cortical astroglia in the development of anhedonia and further support the idea of targeting astroglia for the treatment of depression.

neuroscience↗

Corticosterone as a potential confounding factor in delineating mechanisms underlying ketamine's rapid antidepressant actions

Although ketamine represents a new line of antidepressants with unique clinical advantages, its use as a long-term treatment has limitations, particularly its dissociative/psychotomimetic effects and abuse potential. In rats, we observed that a subanesthetic dose of ketamine (10mg/kg) induced a 3-fold increase in corticosterone (CORT) levels in both serum and brain tissue, within an hour of administration. This increase took place in both male and female rats, in both naive and stressed animals. However, no CORT increase was detected in rats injected with (2R, 6R)-hydroxynorketamine (HNK), an active metabolite of ketamine, that is believed to contribute to ketamines antidepressant effect. In response to the release in CORT, ketamine injected animals displayed a significant increase in the expression of sgk1, a downstream effector of glucocorticoid receptor signaling, in the hippocampus indicating the initiation of a transcriptional program. We hypothesized this surge in CORT release was a manifestation of stress experienced by the rat in response to ketamines psychotropic effects. When sensory perception was blocked under isoflurane anesthesia, administration of ketamine did not increase circulating CORT levels as compared to animals injected with saline. Taken together, ketamine administration triggers a behavioral stress response that has downstream molecular consequences. The resulting CORT release, virtually concurrent with the timing of ketamines rapid-acting antidepressant actions, necessitates the consideration of this pathways potential involvement when trying to dissect out the relevant molecular mechanisms underlying ketamines action.

neuroscience↗