Astrocytic expression of GFAP and serum levels of IL-1β and TNF-α in rats treated with different pain relievers

Sintocalmy, a Passiflora incarnata Based Herbal, Attenuates Morphine Withdrawal in Mice

Chronic opioid use changes brain chemistry in areas related to reward processes, memory, decision-making, and addiction. Both neurons and astrocytes are affected, ultimately leading to dependence. Passiflora incarnata L. (Passifloraceae) is the basis of frequently used herbals to manage anxiety and insomnia, with proven central nervous system depressant effects. Anti-addiction properties of P. incarnata have been reported. The aim of this study was to investigate the effect of a commercial extract of Passiflora incarnata (Sintocalmy®, Aché Laboratory) in the naloxone-induced jumping mice model of morphine withdrawal. In addition, glial fibrillary acidic protein (GFAP) and S100 calcium-binding protein B (S100B) levels were assessed in the frontal cortex and hippocampus, and DNA damage was verified on blood cells. In order to improve solubilization a Sintocalmy methanol extract (SME) was used. SME is mainly composed by flavonoids isovitexin and vitexin. The effects of SME 50, 100 and 200 mg/kg (i.p.) were evaluated in the naloxone-induced withdrawal syndrome in mice. SME 50 and SME 100 mg/kg decreased naloxone-induced jumping in morphine-dependent mice without reducing locomotor activity. No alterations were found in GFAP levels, however SME 50 mg/kg prevented the S100B increase in the frontal cortex and DNA damage. This study shows anti-addiction effects for a commercial standardized extract of P. incarnata and suggests the relevance of proper clinical assessment.

Astroglial correlates of neuropsychiatric disease: From astrocytopathy to astrogliosis

Complex roles for astrocytes in health and disease continue to emerge, highlighting this class of cells as integral to function and dysfunction of the nervous system. In particular, escalating evidence strongly implicates a range of changes in astrocyte structure and function associated with neuropsychiatric diseases including major depressive disorder, schizophrenia, and addiction. These changes can range from astrocytopathy, degeneration, and loss of function, to astrogliosis and hypertrophy, and can be either adaptive or maladaptive. Evidence from the literature indicates a myriad of changes observed in astrocytes from both human postmortem studies as well as preclinical animal models, including changes in expression of glial fibrillary protein, as well as changes in astrocyte morphology and astrocyte-mediated regulation of synaptic function. In this review, we seek to provide a comprehensive assessment of these findings and consequently evidence for common themes regarding adaptations in astrocytes associated with neuropsychiatric disease. While results are mixed across conditions and models, general findings indicate decreased astrocyte cellular features and gene expression in depression, chronic stress and anxiety, but increased inflammation in schizophrenia. Changes also vary widely in response to different drugs of abuse, with evidence reflective of features of astrocytopathy to astrogliosis, varying across drug classes, route of administration and length of withdrawal.

Morphine-Mediated Brain Region-Specific Astrocytosis Involves the ER Stress-Autophagy Axis

A recent study from our lab has revealed a link between morphine-mediated autophagy and synaptic impairment. The current study was aimed at investigating whether morphine-mediated activation of astrocytes involved the ER stress/autophagy axis. Our in vitro findings demonstrated upregulation of GFAP indicating astrocyte activation with a concomitant increase in the production of proinflammatory cytokines in morphine-exposed human astrocytes. Using both pharmacological and gene-silencing approaches, it was demonstrated that morphine-mediated defective autophagy involved upstream activation of ER stress with subsequent downstream astrocyte activation via the μ-opioid receptor (MOR). In vivo validation demonstrated preferential activation of ER stress/autophagy axis in the areas of the brain not associated with pain such as the basal ganglia, frontal cortex, occipital cortex, and the cerebellum of morphine-dependent rhesus macaques, and this correlated with increased astrocyte activation and neuroinflammation. Interventions aimed at blocking either the MOR or ER stress could thus likely be developed as promising therapeutic targets for abrogating morphine-mediated astrocytosis.