2.4. Aerosol THC administration

This was carried out as described previously [13]. THC in ethanol was obtained from the National Institute on Drug Abuse Drug Distribution Program. The solvent was evaporated under N₂, and THC was dissolved in propylene glycol (100 mg/mL) with heat (37°C) and sonication (15 min). Vaporizer tanks (Smok TFV8 Baby) were filled with 3–4 mL of the THC solution immediately before testing. On PND31, 2–3 animals were placed in pairs with familiar cagemates into tub cages with bedding, on the lower shelf of the larger aerosol containment chambers. They received 30 min of THC vapor exposure consisting of ten 5-s puffs every 175 sec. Approximately 5 min after the 30 min session, PK animals were removed and returned to their home cages, and those for grooming evaluation were placed alone into behavioral testing chambers, and were video recorded for 2 h. PK rats were disorientated and decapitated without anesthetic to avoid any interference with isoflurane at various timepoints after exposure (5, 15, 60 min; n = 4 per timepoint), trunk blood was collected into 4 mL polypropylene plastic tubes containing spray-coated potassium-EDTA (K₂-EDTA) and centrifuged at 500×g at 4°C for 10 min. Plasma was collected and centrifuged again at 2000×g at 4°C for 10 min to remove any trace of residual cells and transferred into polypropylene tubes. After decapitation, their brains were quickly removed, and olfactory bulb and cerebellum samples were dissected rapidly. Nasal mucosa were collected after removing dorsal bone anterior to the olfactory bulbs and lung samples were collected. The dorsum of each rat was shaved and approximately 300 mg of fur was collected. All tissue samples were immediately frozen on dry ice, and stored at −80°C until analyses.