Differential gene expression in the rat hippocampus during learning of an operant conditioning task

• Published in: Neuroscience Vol. 163; no. 4; pp. 1031 - 1038
• Main Authors: Rapanelli, M, Frick, L.R, Zanutto, B.S
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 10.11.2009; Elsevier
• Subjects: Animals; Biological and medical sciences; Brain-Derived Neurotrophic Factor - genetics; Brain-Derived Neurotrophic Factor - metabolism; Calcium-Calmodulin-Dependent Protein Kinase Type 2 - genetics; Calcium-Calmodulin-Dependent Protein Kinase Type 2 - metabolism; Conditioning, Operant - physiology; Cyclic AMP Response Element-Binding Protein - genetics; Cyclic AMP Response Element-Binding Protein - metabolism; Cytoskeletal Proteins - genetics; Cytoskeletal Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression; hippocampus; Hippocampus - physiology; learning; Learning - physiology; Male; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Neurology; Proto-Oncogene Proteins c-fos - genetics; Proto-Oncogene Proteins c-fos - metabolism; Proto-Oncogene Proteins c-jun - genetics; Proto-Oncogene Proteins c-jun - metabolism; Rats; Rats, Long-Evans; real-time PCR; RNA, Messenger - metabolism; Synapsins - genetics; Synapsins - metabolism; Time Factors; Vertebrates: nervous system and sense organs; BCTr; CamKII; C; trained; LTP; learning; real-time PCR; Box Control of Trained; Ca 2+/calmodulin-dependent protein kinase II; Box Control of Incompletely Trained; cAMP response element binding; complementary DNA; Control; CREB; RT-PCR; activity-regulated cytoskeleton-associated protein; cDNA; brain-derived neurotrophic factor; Tr; long term potentiation; hippocampus; BDNF; IT; incompletely trained; Arc; BCIT; reverse transcription polymerase chain reaction; Rat; Rodentia; Central nervous system; Gene expression; Encephalon; Learning; Polymerase chain reaction; Vertebrata; Mammalia; Acquisition process; Animal; Conditioning; Hippocampus
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2009.07.037

Abstract Changes in transcription levels of brain-derived neurotrophic factor (BDNF), cyclic adenosine monophosphate (cAMP) response element binding (CREB), Synapsin I, Ca2+ /calmodulin-dependent protein kinase II (CamKII), activity-regulated cytoskeleton-associated protein (Arc), c-jun and c-fos have been associated to several learning paradigms in different brain areas. In this study, we measured mRNA expression in the hippocampus by real time (RT)-PCR mRNA levels of BDNF, CREB, Synapsin I, CamKII, Arc, c-jun and c-fos, during learning and operant conditioning task. Experimental groups were as follows: control (C, the animals never left the bioterium), when the animals reached 50–65% of the expected response (Incompletely Trained, IT), when animals reached 100% of the expected response with a latency time lower than 5 s (Trained, Tr), Box Control of Incompletely Trained (BCIT), animals spent the same time as the IT in the operant conditioning box and Box Control of Trained (BCTr) animals spent the same time as the Tr in the operant conditioning box. All rats were killed at the same time by cervical dislocation 15 min after training and hippocampi were removed and processed. We found increments of mRNA levels of most genes (BDNF, CREB, Synapsin I, Arc, c-jun and c-fos) in IT and Tr groups compared to their box controls, but increments in Tr were smaller compared with IT. These results describe a differential gene expression in the rat hippocampus when the animals are learning and when animals have already learned. Taking together the results presented herein with the known functions of these genes, we propose a link between changes in gene expression in the hippocampus and different degrees of cellular activation and plasticity during learning of an operant conditioning task.