Prevalence, symptoms, and treatment of depression suggest that major depressive disorders (MDD) present sex differences. Social stress-induced neurovascular pathology is associated with depressive symptoms in male mice; however, this association is unclear in females. Here, we report that chronic social and subchronic variable stress promotes blood-brain barrier (BBB) alterations in mood-related brain regions of female mice. Targeted disruption of the BBB in the female prefrontal cortex (PFC) induces anxiety- and depression-like behaviours. By comparing the endothelium cell-specific transcriptomic profiling of the mouse male and female PFC, we identify several pathways and genes involved in maladaptive stress responses and resilience to stress. Furthermore, we confirm that the BBB in the PFC of stressed female mice is leaky. Then, we identify circulating vascular biomarkers of chronic stress, such as soluble E-selectin. Similar changes in circulating soluble E-selectin, BBB gene expression and morphology can be found in blood serum and postmortem brain samples from women diagnosed with MDD. Altogether, we propose that BBB dysfunction plays an important role in modulating stress responses in female mice and possibly MDD.

The objective was to assess the single-dose pharmacokinetics of clonazepam following i.m., p.o. and i.v. administration. In an open-label, three-way crossover study, 12 healthy volunteers were randomized to receive a single dose of 2 mg clonazepam either by the i.m., p.o. or i.v. route. Serial blood samples were collected up to 120 h after drug administration. Plasma concentrations of clonazepam were determined by electron-capture gas-liquid chromatography. The absorption rates of clonazepam after i.m. and p.o. administration of clonazepam were significantly different from each other, as reflected by the respective mean values of maximum plasma concentration (C_max 11.0 vs. 14.9 ng·ml^–1) and time to reach maximum concentration (t_max 3.1 vs. 1.7 h). Secondary plasma peaks of clonazepam were observed in 9 volunteers after i.m. injection (C_max 9.9 ng·ml^–1; t_max 10.4 h). A comparison of the area under the plasma concentration-time curves (AUC) shows that the i.m. route is equivalent to the oral route (AUC_0–∞ 620 vs. 561 ng·h·ml^–1). Clonazepam was almost completely absorbed after i.m. and p.o. administration, as shown by the mean absolute bioavailability of 93 and 90%, respectively. No significant differences existed between the elimination half-lives (i.v. 38.0 h; i.m. 43.6 h; p.o. 39.0 h). The average clearance and volume of distribution (V_Z) were 55 ml·min^–1 and 180 liters, respectively. In conclusion, the observed differences in C_max and t_max after i.m. and p.o. administration were consistent with a slower absorption rate of clonazepam after i.m. injection. The systemic exposure to clonazepam was not affected by the route of extravascular administration. Statistical evaluation of these kinetic data showed differences in the absorption rate, so that clonazepam given by the i.m. route is not bioequivalent to the oral route. On the basis of the results of this study, we would recommend the same i.m. and p.o. dose in epileptic patients, but therapeutic response would be expected to be less predictable and to occur later in the case of i.m. administration.

In 9 drug-resistant patients with partial seizures treated with vigabatrin, gamma-vinyl GABA (VGB), alanine aminotransaminase (ALAT) activity in plasma was significantly reduced. Comparison of in vitro with in vivo measurements led us to conclude that this reduction is mainly an in vivo phenomenon, perhaps due to cross-enzyme inhibition. The assessment of two biological variables linked with ALAT, glucose and alanine levels under fasting conditions, failed to show any significant metabolic alterations. VGB is an effective drug for partial epilepsy. Our observations do not suggest that reduced ALAT activity is of clinical concern.

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