Ketamine hcl

All compounds were administered by intraperitoneal (ip) or subcutaneous (sc) injection in a volume of 10 mL/kg of body weight. Fentanyl citrate (Sigma-Aldrich, St. Louis, MO, USA), VRP26 TFA, methylnaltrexone HBr (MNTX) (Sigma-Aldrich, St. Louis, MO, USA), ketamine HCl (Henry Schein, Wixom, MI, USA) and xylazine HCl (Akorn, Decator, IL, USA) were dissolved in sterile saline (0.9% NaCl w/v), SNC80 was dissolved in 3% (v/v) 1 M HCl and brought to volume with sterile water. Naltrindole HCl (NTI) (Tocris Biosciences, Minneapolis, MN, USA) and carprofen (Zoetis Inc., Kalamazoo, MI, USA) were prepared in sterile water.

For intravenous self-administration and reinstatement testing, rats were anesthetized with ketamine HCl (100 mg/kg, i.p.; Henry Schein, Melville, NY) and xylazine (2 mg/kg, i.p.; Henry Schein, Melville, NY) and surgically implanted with indwelling venous catheters. Rats that received intra-cranial micro-infusions prior to reinstatement testing also had bilateral guide cannula targeting the prelimbic cortex. All procedures are described in detail in the supplemental information.

The cfos^GFP mice were injected with either saline (10 mL/kg, i.p.; sodium chloride 0.9%, Hospira), ketamine (10 mg/kg, i.p.; ketamine HCl, #055853, Henry Schein), or psilocybin (1 mg/kg, i.p.; Usona Institute). At 3.5 hours after the injection, the mice were deeply anesthetized with isoflurane and transcardially perfused with phosphate buffered saline (P4417, Sigma-Aldrich) followed by paraformaldehyde (PFA, 4% in PBS). The brains were fixed in 4% PFA for 12 hours at 4°C. Brains were transferred to PBS with 0.1% sodium azide until they were sectioned and imaged. Whole-brain serial two-photon tomography imaging was performed using the previously described TissueCyte 1000 system^{80 (link)}. Briefly, brain samples were imaged using a laser with an excitation wavelength of 920 nm, and emitted fluorescence was captured across three channels (channel 1: 560–680, channel 2: 500–560, and channel 3: 400–500 nm). GFP fluorescence was detected in channel 2. Autofluorescence signals were detected in channel 1 and 3. Approximately 140 serial block-face images were acquired at 100-μm spacing for each brain at 1.4 μm/pixel XY sampling. The imaging steps were done blinded to the treatment conditions at TissueVision, Inc (Newton, MA).