Modulation Of Glucose Transport By The Lateral Walls Of Cochlear OHCs

Cochlear hair cells are composed of inner hair cells(IHCs) and outer hair cells(OHCs).The function of inner hair cells in the cochlear is to convert acoustic signal into nerve impulses. As a part of the corti sensors, the outer hair cells function mainly as a sound mechanical stimulation of effector., namely modifying the transmitting process before the acoustic signals is transmitted to the the inner hair cells in order to guarantee fine sound resolution and wide scope of the intensity of feeling. The process mainly rely on the outer hair cells electromotility. When the mammalian outer hair cells is activated by electrical stimulation, the length of outer hair cell’s body can change rapidly along with the frequency change. Motion frequency of the outer hair cell’s body is up to tens of thousands of Hertz. Such a high frequency of cell contractions inevitably is accompanied by a large amount of energy material consumption, but the outer hair cells’ movement does not depend on the ATP, therefore how to transport the energy material of the outer hair cells, what is function of the special three layer structures of the outer hair cells’ membrane and which role the transmit process plays in electromotility of the outer hair cells are still unknown. Most mammalian cells mainly absorb basic energy material through the cell membrane transporters, so are the outer hair cells. Due to the speciality of outer hair cell membrane structure, the outer hairs’ lateral plasma membrane is made up of the plasma membrane, the lateral cisternae, and the cortical cytoskeletal lattice. At the same time, the current study of outer hair cells energy material transport is less, so whether the structure of outer hair cell lateral wall is involved in the transport of basic energy material and how to transport is still unkown currently. Glucose is the basic energy material. Through the process of glucose absorbtion watched by living cell confocal microscopy, we can find that the outer hair cells can absorb glucose, and the quantity of outer hair cells to absorb glucose can increases with the increase of glucose concentration and time. Through immunohistochemical experiments, it illustrates the distribution of each types of glucose transporter of outer hair cells. We can find that most of the glucose transporters distribute point of outer hair cells in the lateral membrane and the cytoplasm, and the distribution of glucose transporter 1 and the glucose transporter 4 is more. The Glut-4 mainly distributes in the inner side of the lateral membrane of cochlear outer hair cells. Then we observe the process of glucose absorption of the outer hair cells after we join Glut- 1-4 inhibitors into the culture fluid. We find that the amount of glucose absorption is significantly reduced and the degree of decrease is different, therefore we conclude that the glucose absorption process of the outer hair cells can be controlled. By comparing the distribution location of Glut- 4, prestin and the P2X7, all of these three structures distribute on the lateral wall of outer hair cells, and the three position distribution is extremely similar. At the same time after joining P2X7 receptor agonist ATP we can find that the quantity of outer hair cells to absorb glucose increased significantly. According to the above experiments we conclude that glucose transport into outer hair cells by glucose transporters, and this process can be controlled. Each glucose transporter distributes on the lateral wall of outer hair cells, so we can know that the outer hair cell lateral wall involve in basic energy material transport. Because the distribution location of Glut- 4, prestin and P2X7 is very close, there may be some links between the three, but still needs further research to explore.