Study On Like-Muscarinic Acetylcholine Receptor In Plyhachis Vicina Rogher And Apis Mellifera Ligustica Spinola

The cholinergic system plays an important role in the central nervoussystem of insects and is closely related to a complicated behavior of insects. Scientistsalways pay close attention to the cholinergic system which participates in feeling,movement, memory, learning and other cognitive processes. There are two main typesof cholinergic receptors-nicotinieand muscarinic acetylcholine receptors. In mammal,muscarinic receptors are further classified into M1-M5 subtypes. M1, M3 and M5receptor subtypes have a stimulatory effect on the target tissue, whereas the M2 and M4subtypes are inhibitory. Now, all of insect muscarinic acetylcholine receptors couple tostimulatory G-proteins, and induces adenylate cyclase activity. And the insects M2receptor (inhibitory receptor) hasn't been reported up to now.The social insects whose behavior is complex own deweloped neural system. As thetypical eusocial insects, both Plyhachis vicina Rogher and Apis mellifera ligusticaSpinola have a strict hierarchical division of labor in the group which is mostly dividedinto three castes: male, female (queen) and worker, they are different each other inmorphology and physiology. At the same time, Plyhachis vicina Rogher is also animportant medical insect and Apis mellifera ligustica Spinola is bred to produce honeywidely in our country. In this study, we took Plyhachis vicina Rogher and Apis melliferaligustica Spinola as experimental animals. The immunohistochemical technique and thebioinformatics method were performed to study the expression of like-muscarinicacetylcholine receptor M2 in the different tissues of ant (P. vicina) and the bee (A.m.ligustica) and predict the function of like-muscarinic acetylcholine receptor in socialinsects. The main results describe as follows:1. Like-muscarinic acetylcholine receptor M2 is expressed in the brain of thedifferent caste Polyrhachis vicina Rogher and shows the different localization in thedifferent caste, which suggests that like-M2 receptor had a different effect on specialbehavior of different caste. Antenno-cerebral tracts, such as inner antenno-cerebraltracts, middle antenno-cerebral tract and outer antenno-cerebral tract exhibit like-M2receptor immunoreactivity. 2. HE stain is performed to observe the brain of worker bee (A.m. ligustica). Theresult indicated that the brain structure is composed of anterior, middle and hindbrain.Like-M2 receptor is expressed in the brain of worker bee (A.m. ligustica), which differsfrom worker ant (P. vicina). Like-M2 receptor immunoreactivity is showed in the nervefiber tract between lateral horn and mushroom body, lateral protocerebral lobe, ventralposterior optic commisure and subesophageal ganglion.3. In the peripheral nervous system, especially neuromuscular junction, like-M2receptor is widely expressed in the musculature of Plyhachis vicina Rogher. Thesnodgrass of worker ant (P. vicina) and the longitudinal and dorsoventral of male ant (P.vicina) exhibit like-M2 receptor immunoreactivity. Besides, the neuromuscular junctionof thorax in the worker bee (A.m. ligustica) shows the same results.4. Apis mellifera similar to muscarinic acetylcholine Receptor gene (XM₃95760),which Was registered in GenBank, was analyzed and predicted by the tools ofbioinformatics in the following aspects: the composition of EST sequences, theorientation of chromosome, the composition of amino acid sequence, equipotential,transmembrane topological structure, hydrophobicity or hydrophilicity, the comparisonof homologous proteins in other species and so on. Combined experiment conclusionwith predicted information in the PROSITE database, we analyzed conservativesequences and found the functional regions of this protein. At last, we reconstructedphylogenetic trees for mAchR in 12 species using Mega 3.0.This study gives the first account of the representation of like-muscarinicacetylcholine receptor M2 neuronal systems in the brain of insect. The results show thatlike-M2 receptor is widely distributed in the brain of Plyhachis vicina Rogher and Apismellifera ligustica Spinola. But People pay less attention to insect muscarinicacetylcholine receptor. We find that like-M2 receptor exists in the social insects in orderto further research the structure and function of insect acetylcholine receptor andaccumulate datum about insect neurophysiology.