Date Published: , 2011
Publisher: A.I. Gordeyev
Author(s): E.S. Severin, M.V. Savvateeva.
Molecular physiology is a new interdisciplinary field of knowledge that looks into how complicated biological systems function. The living cell is a relatively simple, but at the same time very sophisticated biological system. After the sequencing of the human genome, molecular physiology has endeavored to investigate the systems of cellular interactions at a completely new level based on knowledge of the spatial organization and functions of receptors, their ligands, and protein-protein interactions. In recent years, the achievements in molecular physiology have centered on the study of sensor reception mechanisms and intercellular data transfer, as well as the immune system physiology, amongst other processes.
When considering the functioning mechanisms of membrane receptor systems, it is necessary to first highlight the achievements in molecular physiology regarding the process regulation that occurs in the cell, as well as the intracellular transmission of hormonal signals. The concept of secondary messengers (secondary mediators) is considered today fundamental in cellular and physical-chemical biology, as well as in molecular medicine. However, towards the end of the 1950s the discovery of the first biologically active substance with signal-transduction functions – cAMP – had upended concepts regarding biochemical process regulation in the cell and the intracellular mechanisms of signal transduction. It appears that the signal molecules not able to cross through the cellular membrane interact with the specific receptors and enzyme systems located on the membrane’s external surface. Thus, through interaction with membrane receptor systems, biologically active substances determine the production of one or several secondary messengers; low-weight biologically active molecules which transmit signals on intracellular effector structures. Currently, more than 10 similar molecules have been described – they are as follows: cyclic nucleotides cAMP and cGMP; inositol exchange products – inositol phosphate (IP3); diacylglycerol (DAG), as well as Ca 2+ ions; polynucleotide oligoA; nitrogen monoxide (NO); arachidonic acid exchange products; and a number of other substances of lipid-origin (Fig. 1).