Clozapine

2-Bromoterguride (Alfarma sro, Cernosice, Czech Republic) was suspended in 15% Cremophor® EL (Sigma-Aldrich, Steinheim, Germany), phencyclidine hydrochloride (Sigma-Aldrich, Steinheim, Germany) and haloperidol (Janssen Pharmaceuticals, Beerse, Belgium) were dissolved in 0.9% saline. Apomorphine hydrochloride hemihydrate (Sigma-Aldrich, Steinheim, Germany) was dissolved in 0.2% ascorbic acid solution, aripiprazole (Toronto Research Chemicals, Toronto, Canada) in 30% N,N-dimethylformamide and blended in 0.5% acetic acid. Clozapine (Abcam Biochemicals, Cambridge, UK) was dissolved in 0.1 N HCl and adjusted to pH neutrality. Compound doses and the elicited effect on behavior were thoroughly evaluated in pilot studies prior to the PPI, NOR, and social interaction experiments. All drugs were freshly prepared on the day of injection and administered in a volume of 1 ml/kg body weight.

hCMEC/D3 is an immortalised human brain microvascular endothelial cell line derived from human temporal lobe microvessels isolated during surgery. These cells have been extensively characterised as a model for human endothelial cells of the BBB [39 (link)]. Vials of cells at passage 28 were kindly supplied by Dr. P.O. Couraud (INSERM, Paris, France). Cells were grown and maintained in complete media at 37 °C and 5% CO₂ and used between passages 29–35.
Confluent cells were treated with 0.02 ng/ml, 0.2 ng/ml, 2 ng/ml or 20 ng/ml recombinant human IL- 1β (Thermo Fisher) for 48 h and harvested for RNA extraction, followed by cDNA synthesis. In separate experiments, 1.2 µM clozapine (Abcam, Cambridge, UK), 26.6 nM haloperidol (Abcam) and 0.974 µM risperidone (Abcam) (based on typical therapeutic serum ranges) were used to treat the confluent culture for 48 h before harvesting the cells. This time point was chosen to avoid an immediate (acute) response to antipsychotic treatment. ICAM1, ABCG2, CDH5, OCLN and IFITM mRNA expression was measured by qPCR (supplementary information).

Clozapine (Abcam Biochemicals,
Cambridge, U.K.)
was dissolved in 0.1 N HCl supplemented with distilled water to the
appropriate volume (final pH = 5.0–6.0). PCP HCl (Sigma-Aldrich),
ondansetron (Tocris, U.K.), SB399885 (Tocris, U.K.), FPPQ, and CPPQ ((S)-1-[(3-chlorophenyl)sulfonyl]-4-(pyrrolidine-3-yl-amino)-1H-pyrrolo[3,2-c]quinolone)^{29 (link),67 (link)} were dissolved
in distilled water. All compounds were administrated in a volume of
1 mL/kg.