P50 Project 2: Socially-acquired nicotine self-administration

Study title

P50 Project 2: Socially-acquired nicotine self-administration

Description

P50 Project 2: Socially-acquired nicotine self-administration

Funding sources

P50DA037844

Methods for genotype

1) Genotypes were generated as described in [PMID: 23979941, DOI: 10.1534/g3.113.007948] 2) low-coverage WGS based on Riptide library preparation (pulication in progress)

Methods for Phenotypes

Open Field:Two OFT arenas were constructed using black acrylic glass, measuring 100 cm (L) × 100 cm (W) × 50 cm (H), which were placed side by side. The floors were covered by wood boards painted with either black or white acrylic paint (ART-Alternatives, ASTM D-4236, Emeryville, CA, USA) to contrast the coat of the animals (i.e., a black board was used for rats with white fur). The test chambers were illuminated by a long-range, 850-nm infrared light (LIR850-70, LDP LLC, Carlstadt, NJ) located 160 cm above the center of the two test chambers. No source of visible light was present during behavioral testing, with the exception of a flat panel monitor (Dell 1908FP). A digital camera (Panasonic WV-BP334) fitted with an 830 nm infrared filter (X-Nite830-M37, LTP LLC, Carlstadt, NJ) and located next to the infrared light source was used to record the behavior of the rats. All rats were released at the same corner of the test chamber, and data were collected for 1 h.

Novel Object Interaction Test:This test was conducted the day after the OFT in the same arena. A cylindrical rat cage constructed using 24 aluminum rods (30 cm in length) spaced 1.7 cm apart was used as the novel object. The bottom and top of the cage (15 cm in diameter) were manufactured using a 3D printer from polylactic acid. The design can be downloaded from Github . The novel object was placed in the center of the arena before testing. The test duration was 20 min and was recorded using the same camera as that used in the OFT.

Social Interaction Test:This test was conducted the day after the NOIT. This test compares the preference of a subject rat for a stimulus rat restricted in a cylindrical cage (i.e., the novel object used in the NOIT) against an empty cylindrical cage. The test arena was reduced to 100cm(L) × 60cm(W) × 50cm(H) by using a black board placed vertically in the arena. Two cylindrical cages described above were placed ~30 cm away from the walls on opposite sides (i.e., similar to the arrangement commonly used in the three-chamber test). A randomly selected stimulus Sprague-Dawley rat of the same sex and similar weight as the HS test rat was placed into one of the cylindrical cages (kept the same throughout the experiment) 5 min before the HS subject rat was placed into the arena. The stimulus and subject rats were never housed together and thus were unfamiliar to each other. No social isolation was conducted on either rat. Each stimulus rat was used no more than once per day. The test duration was 20 min and was recorded using the same camera as that used in the OFT.

Nicotine self-administration:*Was conducted via jugular catheter. Two drinking spouts, each connected to one lickometer controller, were fitted on the same wall of the operant chambers (Med Associates, St Albans, VT). A white cue light and a tone generator were located on the same wall as the drinking spouts. SA was conducted using a fixed ratio 10 and 20-s time-out schedule. Thus, 10 licks on the active spout triggered the concurrent delivery of 60 μl OG cue to the spout and 50 μl of nicotine (or saline) through the jugular catheter.

Progressive ratio testing:was conducted on day 11 of SA in one experiment. The number of licks to obtain subsequent infusion was determined using the exponential formula

Methods for Omics

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Data Freezes

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