Observation On The Function Of CREB In Learning And Memory In Polyrhachis Vicina Roger

Ants are social insects with clear division of labor.They are composed of five castes:females, males, soldiers, big workers and small workers. The polymorphism and clear division of lab lead to their developed nerve system. It is an important part in insect brain nerve research to analyze their brain nerve system. Polyrhachis Vicina Roger is a robust and black ant of Asia, which lives in the clump of bushes or arbors on hillsides where the major plant is Pinus massoniana Lamb. , Guercus fabric Hance , Arundinella setosa Trin and so on. A population, from Yongkan, Zhejiang of China, comprised polygynous colonies that generally had queens, females, Males, larvae, pupae, eggs and workers(Chen et al., 1989). The polymorphism and clear division of lab decide that they have complex and developed neural system, take the volume of mushroom body in different insects as example, ant is 1/174, but Melolontha is only 1/3290, and Dytisws is 1/4200.CREB(cAMP response element binding Protein) was discovered in the late 1980s. CREB with a relative molecular weight 43000 whose peptide chain is composed of 341 amino acid residues.It' s molecular structure is divied into two regions, the N-terminal domain regulates gene transcription, and the C-terminal domain is a promoter DNA-binding area. CREB is a member of the CREB/ATF family.it contains 8 subtype molecules. CREB as a transcri ptional regulation factor in eukaryotic cell carries out the function by itself phosphorylation.People pay particularly attention to the role of CREB in learn and memory. CREB can promote the formation of long term memory in drosophila and mouse.In this study, we took P. Vicina as material and method of immunochemistry, for the first time, study the expression of CREB in different ant castes. We trained the work ant through behavioral method to study the ability of learning and memory of P. Vicina, and compaired the difference of CREB expression before training to find if the level of CREB changed in the process of LTP. This paper also want to looking for asuitable method to know more information, it' s about the study of brain structure and nerve pathway of P. Vicina in the study.The results show that polyformaldehyde has good effect as fixation liquor in paraffin embed. The brain of ant can be immerged in few time, and 2h is a suitable time for gradual dehydration by.alcohol. Lucency are used by dimethylbenzene. The result indicated that the brain structure are composed of anterior, middle and hindbrain. A gigantic mushroom body in anterior showed that the ant has transcendent capability in learning and memory. There is big olfactory nerve fiber globe in middlebrain, which Indicated that P. Vicina ant has well developed olfactory system. However, the optic system' s function in looking for food, learning, memor y and other behavior is inferior to olfactory globe. The hindbrain is very small, and its function is not clear as yet.To explore the expression of cAMP response element binding protein (CREB) in the ant brain , immunohitochemical technique was performed to detect the expression of CREB in the brain. The results show that a positive expression of CREB was observed in the brain of work ants and queen ants, but on it is the contrary in the males. It may indicated that different castes of P. Vicina associated with different ability of learning and memory. The males' s ability is of a sort or they have another signal transduction pathway. From the slice we can observed that the positive expression in queen ant is mainly expressed at middlebrain. Middlebrain is the internuncial centre of olfaction, so the olfactory function has a special status compaired with vision and it has an important function in-the mode of learning and memory. In work ants, the positive expression of CREB is mainly distribute at mushroom body > optic system and middlebrain, the degree of expression is the most in the three castes. In male ants, the low positive expression of CREB is distribute at middlebrain.We trained the work ants of P. Vicina by Y-maze, and compaired the expression of CREB of the work ants with without training work. As the result we find that the ability of learning and memory in work ants of P. Vicina is obvious, but there have no obvious difference before and after training. In the immunochemistry slices the results indicated that thefunction of CREB is runed through phosphorylating or there' s other signal pathway about learning and memory. From the research we find that olfaction has some important function in learning and memory for P. Vicina.In this paper we firstly study the condition of immunochemistry of P. Vicina. , and investigate the expression of CREB in different ant castes, further more we trained the P. Vicina. and compared the expression of CREB for the sake of proving the function of CREB of P. Vicina in learning and memory.