Conditioned place preference D1-cre. Chemogenetic inhibition during retrieval
Figure 4E. Mice strain: D1- Cre/WT Viruses- AAV2-hSyn-DIO-hM4Di Coordinates:±2.82,1,-3.69 WT;#n=7 hM4Di/CNO;#n=5 Apparatus: Each place conditioning apparatus consists of an open field enclosed in separate light- and sound-attenuating chambers. General activity and location in the open field was monitored by video recording. The floor of the open field consisted of interchangeable halves made of one of two textures. The combination of floor textures was selected on the basis of calibration studies observing that mice spend an average of about 50% time on each floor type during preference tests. Thus, the apparatus is "unbiased". Specifically, the floors are either of a rough "crushed ice" texture, coupled with walls on which appear black dots vs. a smooth floor texture coupled with walls on which appear vertical black lines. Prior to and following each session the open field and floors was cleaned using a solution of 5% virusolve. Procedures: An unbiased conditioning procedure consists of the following phases: Handling: 30-min sessions. Pre-conditioning bias test: a single 20 min test session is conducted during which mice are allowed to freely explore the open field with half of the arena containing the "crushed ice" floor and dots walls and half of the arena containing the "smooth" floor and straight lines walls. Conditioning: 3 days 2 session/day. Mice are randomly assigned to one of two groups, pairing cocaine (10 mg/kg IP) to either the ‘crushed ice’ or ‘smooth’ contexts, while saline conditioning (10 ml/kg) occurred on the opposite context. On all sessions, mice have access to the entire apparatus with the same floor and walls type on both sides. Post-conditioning bias test: identical to Pre-conditioning. Each CPP experiment was performed on a different group of mice, where Pre-conditioning and Post-conditioning bias test was measured within the same group of mice. For chemogenetic inhibition during conditioning, CNO (10 mg/kg, IP) was injected 30min prior to cocaine. For chemogenetic inhibition during retrieval, mice went through the regular CPP protocol, including a retrieval test, following which they were subject to another conditioning day and finally, to an additional test 30min after CNO (10 mg/Kg, IP) injection.