Anti-ET-B

Anti-ET-B

Western blotting of rat brain membranes: 1.  Anti-ET-B antibody (1:200). 2.  Anti-ET-B antibody, preincubated with the control peptide antigen.

Immunohistochemical staining of rat dorsal peri-ventricular thalamus using Anti-ET-B antibody (#AER-002).  Counterstained with cresyl violet.  The specific staining is black.

Endothelins (ET-1, 2, and 3) are considered to be very powerful vasoconstrictive substances. In humans, endothelins mediate their actions via two specific G-Protein coupled receptors, ET_AR and ET_BR. Both ET_AR and ET_BR are present in the heart and in human myocardium at similar levels.^1,2

The endothelin receptors differ in their ligand specificity. While ET_AR has varying affinities for the endothelin isoforms (ET-1 >ET-2>ET-3), ET_BR shows no selective affinity.^2,3  Subsequent studies have demonstrated the presence of endothelins in vascular as well as in non-vascular cells and tissues, having multiple biological activities.

Currently there is increasing evidence that ET-1 may modulate mitogenesis, apoptosis, angiogenesis tumor invasion and the development of metastases.³

Until recently, it was thought that all cellular activities of the endothelins were mediated through their interactions with their cell surface receptors. However, a recent study demonstrated that cardiac nuclei also possess both ET_AR and ET_BR subtypes, which are functional and coupled to signaling mechanisms within the nuclear membrane.²

Hypermethylation of the ET_BR correlated with transcriptional down-regulation and reduced expression of ET_B receptor was observed in several prostate, bladder and colon cancer cell lines.³