75 Pharmacology The different cloned MEL receptor subtypes that are required to perform specific functions possess intrinsic selleck chemicals Dasatinib differences. This is evident in terms of both the cell tissue distribution and the signal transduction pathways involved. Over the next few years, the identification of the links between specific target sites for MEL, specific MEI , receptor subtypes, and particular http://www.selleckchem.com/products/arq-197.html physiological actions will be a great Inhibitors,research,lifescience,medical challenge. For this, many more pharmacological investigations are required. There

is especially a great, need for selective agonists and antagonists. Many such pharmacological studies have been done31,32,45,57 and are still performed in native tissue models, especially ovine PT cells and amphibian melanophores. Advances in the molecular biology of MEI , receptor subtypes, however, have permitted

the development of gene cloning and expression technologies. Different cell lines (COS-7, NIH-3T3, and CHO) expressing high levels of specific recombinant receptors (either Inhibitors,research,lifescience,medical hMT1 or hMT2) provide the means for a rapid characterization of receptor-mediated ligand binding and functional responses. Numerous agonists and antagonists have been developed and are already available (Tables I and II) 34,57,46,76-92 and the further development, in the engineered cell systems will quickly increase Inhibitors,research,lifescience,medical this number. In addition to their usefulness as pharmacological tools for studying the physiological role of MEL receptor subtypes, they have started to be tested for clinical applications mostly for circadian-bascd disorders. However, presently, in all recombinant systems used, no MEL

receptor agonist Inhibitors,research,lifescience,medical with a rate of selectivity over 100 for MEL receptors subtypes in intact tissues is currently available.80 However, some partial agonists or antagonists have selectivity above 100 and could be considered as selective MT2 analogues, and thus be used to distinguish the MT2 from MT1, receptors in mammalian tissue. Table I. Melatonin receptor agonists. Specific and currenty used molecules are presented in bold. Agonist are considered as specific when the MT1/MT2 or MT2/MT1 ratio obtained in recombinant melatonin receptors is >100. *On dopamine Inhibitors,research,lifescience,medical Anacetrapib release in retina; … Table II. Melatonin receptor antagonists. Specific and currently used molecules are presented in bold. Antagonists are considered as specific when the MT1/MT2 or MT1/MT2 ratio obtained in recombinant melatonin receptors is >100. #In HEK293 expressing recombinant … Role of melatonin Melatonin and seasonal functions Environmental lighting acting through the eyes in mammals has a profound effect on the rhythm of MEL synthesis. The duration of the peak of MEL secretion is positively correlated with the length of the night. It is through these changes in duration of MEL synthesis that the brain is able to integrate photoperiodic information. This explains the present use of this hormone in farming to control seasonal functions (eg, fur growth, reproduction, and milk production).