Endothelin 3 human, rat has been used for culturing neural tube explant culture, and the pharmacological study of endothelin receptors.
Endothelin 3 (ET3) belongs to endothelin peptide family, which includes three members, ET-1, -2 and -3. These are 21-amino acid peptides, which are synthesized as precursors. They are converted to biologically active peptides, after being cleaved by proteases. There are two endothelin receptors called ETRA and ETRB, and ET3 binds to ETRB. It is localized to human intestine and colon.
Endothelin 3 (ET3) is a vasoconstrictor that acts in a paracrine and autocrine manner, and in intestinal lamina propria causes the degranulation of mast cells. It results in the release of ions from intestinal epithelial cells. In acute and chronic intestinal inflammation, it is overexpressed. It is also up-regulated in colon carcinoma, where it supports cell proliferation and survival. It might be involved in colon homeostasis, and is essential for the survival and proliferation of goblet cells. In mice, it is essential for the development of pigment cells derived from neural crest (NC). Its expression is de-regulated in metastatic melanoma.
Endothelin-3 at low concentrations may attenuate inflammatory responses via ETB2 activation and NO production. Endothelin-3, which acts mainly on ETB, at low concentrations specifically inhibited platelet-activating factor (PAF)-induced paw oedema, whereas neither ET-1 nor Endothelin-2, both of which act on ETA and ETB, showed inhibitory activity. The inhibition by ET-1 and Endothelin-3 (each 0.5 pmol/paw) in the presence of BQ-123 (66.4 ± 6.7 % and 65.4 ± 22.6 %, respectively), is comparable to that by Endothelin-3 (0.5 pmol/paw) alone (65.4 ± 10.9 %), whereas neither ET-1 nor Endothelin-3 in the presence of BQ-788 showed inhibitory activity[3].
