For Western blot analysis, 0, 30 and 60 min after the vehicle or URB597 administration, male mice were sacrificed by decapitation, hippocampus was dissected, flash frozen and stored at −80°C. Tissue homogenates from the hippocampus containing freshly added 1% protease inhibitor mixture (Roche, Indianapolis, IN, USA) and phosphatase inhibitors were centrifuged at 7700 g for 1 min, and the supernatant (total extract) was aspirated and stored at −80°C until use. The pellet (nuclear fraction) was then resuspended in a nuclear extraction buffer (Grabowski, 2005 (link)) and nuclear fraction was prepared as described before (Basavarajappa and Subbanna, 2014 (link)). The supernatant was used to prepare plasma membrane (PM) fractions as described before (Basavarajappa et al., 1998 (link); Basavarajappa and Hungund, 1999 (link); Basavarajappa et al., 2006 (link); Subbanna et al., 2013 ). The nuclear and PM fractions were stored at −80°C until use. The samples were prepared in a sample buffer as previously described by our laboratory (Basavarajappa et al., 2008 (link); Subbanna et al., 2013 ). The blots were incubated in primary antibody; anti-rabbit-CB1R (0.1μg/ml, Thermo Scientific, Waltham, MA), anti-mouse CaMKIV (Sc-55501, 1: 1000), anti-rabbit pCaMKIV (Sc-28443-R, 1: 1000) (Santa Cruz Biotechnology, Santa Cruz, CA, USA), anti-rabbit p44/42 MAPK (ERK1/2) (# 9102, 1:2000), anti-rabbit-phospho-p44/42 MAPK (# 9101, 1:1000), anti-mouse-β-actin (#3700, 1:1000, Cell Signaling Technology, Danvers, MA, USA), anti-mouse-pCREB (Ser133) (# 05-807, 1:1000) and anti-rabbit-CREB (# 04-218, 1:1000) (Millipore, Billerica, MA, USA) for 3 h at room temperature or overnight at 4°C and processed as previously described by our laboratory (Basavarajappa et al., 2008 (link)).