Regulation of trophoblast invasion by endometrial factors

Abstract

This chapter discusses endothelins and sarafotoxin in neural tissues. Endothelins and sarafotoxins belong to the same family of closely related, 21-amino acid residue peptides. They have powerful vasoconstricting and cardiotonic properties. Sarafotoxins are purified from the venom of the snake Atractaspis engaddensis. Among the four different isolated toxins, sarafotoxin S6b is the most potent. Endothelin-1 (Et-1) is produced by vascular endothelial cells and can act as a paracrine factor that regulates the vascular tone. Radiolabeled endothelin peptides with specific radioactivities of about 2000 Ci/mmol and unlabeled peptides are all commercially available from a diversity of sources. Binding experiments are performed using tissue or cell homogenates or intact cells using conventional methods. The chapter additionally explains the identification of receptor subtypes using binding experiments. Receptor heterogeneity is a complicating factor when labeled Et-1 is used to titrate binding sites in membrane or cell preparations. The chapter presents two types of experiments to characterize receptor subtypes.