Serotonin (5-hydroxytryptamine) is an ubiquitary monoamine acting as one of the neurotransmitters at synapses of nerve cells. Serotonin acts through several receptor types and subtypes. The profusion of 5-HT receptors should eventually allow a better understanding of the different and complex processes in which serotonin is involved. Its role is expected in the etiology of several diseases, including depression, schizophrenia, anxiety and panic disorders, migraine, hypertension, pulmonary hypertension, eating disorders, vomiting and irritable bowel syndromes. In the past 20 years, seven distinct families of 5-HT receptors have been identified and various subpopulations have been described for several of them. Increasing number of 5-HT receptors has made it difficult to unravel the role of 5-HT receptor subpopulations due to the lack of suitable selective agents. The present review describes the different populations and nomenclature of recently discovered 5-HT receptors and their pharmacological relevance.

Remodeling of extracellular matrix is crucial for many physiological (cell migration, proliferation, growth, and development) and pathological (remodeling of heart, carcinogenesis, metastasis, etc.) events. Thus, the interaction between cells and extracellular matrix plays a key role in normal development and differentiation of organism and many pathological states as well. Changes in extracellular matrix are regulated by a system of proteolytic enzymes that are responsible for proteolysis of huge quantity of extracellular matrix components. Matrix metalloproteinases (MMPs) represent the main group of regulating proteases in ECM. Ability of matrix metalloproteinases to modify the structural integrity of tissues is essential for certain aspects of normal physiology and pathology. The ability to process molecules such as growth factors, receptors, adhesion molecules, other proteinases, and proteinase inhibitors makes MMPs potent controllers of physiological and pathological events in the cell microenvironment. Overactivation of MMPs has been implicated in numerous disease states.

The extracellular matrix (ECM) provides a physical framework for the cells and functions as a gel medium. Remodeling of the ECM is crucial during physiological cell migration, proliferation, growth, and development. Thus, the interaction between cells and the ECM plays a key role in normal development and differentiation of organisms. However, remodeling of the ECM also occurs in many pathological states. Changes in the ECM are regulated by a system of proteolytic enzymes that are responsible for the proteolysis of a huge quantity of ECM components. Matrix metalloproteinases (MMPs) represent the main group of regulating proteases in the ECM. By regulating the composition and integrity of the ECM, this group of enzymes is essential for cell proliferation, differentiation, and processes of apoptosis. However, deregulation or activation of MMP expression is a feature of numerous pathologic conditions including tumorigenesis and metastasis. The aim of this article is to provide a brief overview of MMPs, their nomenclature and structure, and their role in the development of tumors and metastases.

Myocardium is comprised of a number of cell types. Although most plentiful by volume, cardiac myocytes are greatly outnumbered by nonmyocyte cells, the latter constituting approximately 70% of all myocardial cells, of which approximately 90% are cardiac fibroblasts (CFBs). To maintain the integrity of the cardiac extracellular matrix (ECM) is one of the primary functions of cardiac fibroblasts. ECM represents a network structure that provides the structural and functional integrity to the heart. Besides that, it also contains a high number of cytokines and growth factors with effects on cardiac function and cardiac cells. Cardiac ECM also mediates the mechanical connection between the cardiomyocytes, CFBs, and blood. In addition to producing ECM proteins, CFBs also produce ECM-regulatory proteins -matrix metalloproteinases (MMPs), which can degrade ECM proteins -and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). To date, 26 MMPs have been cloned and characterized in vertebrates. From these, MMP1, MMP3, MMP8, MMP13, MMP2, MMP9, MMP12, MMP28, and the membrane-type MMPs (MT1-MMP/MMP14) have been identified to be involved in the myocardial remodeling. The role of higher MMPs in the cardiovascular system is less well explored.

Based on the results of our study, we suggest that thyroid diseases of a mother might participate in congenital malformations of their newborn, although no direct association between thyroid autoantibodies and congenital malformations has been described as of yet.