Introduction
Eledoisin is an undecapeptite of mollusk origin, which was first separated from posterior salivary glands of two mollusk species Eledone muschata and Eledone belonging to the octopod order of Cephalopoda by De Marco and Gatti in 1975. It belongs to the tachykinin family of neuropeptides, with the molecular weights 1188.4 Da having an amino acid sequence pGlu-Pro-Ser-Lys-Asp-Ala-Phe-Ile-Gly-Leu-Met-NH2 and a molecular formula of C54H85N13O15S, and is widely used as a vasodilator and a contraction agent of extravascular smooth muscle.
Pharmacologic action
Eledoisin, a tachykinins from amphibians and molluscs, also can react with the same three sites that reported to bind selectively to three mammalian tachykinin or neurokinins (substance P, neurokinin A and neurokinin B) called the NK-1, NK-2 and NK-3 sites. The eledoisin-preferring SPE receptor may represent mixtures of binding sites that are no longer considered to be a distinct neurokinin site owing to its special properties as the result of the low selectivity of eledoisin for mammalian receptors.
Function
Similar to other tachykinins from nonmammalian sources, such as kassinin and physalaemin, this undecapeptite also performs a comprehensive and complicated spectrum of pharmacological and physiological activities including powerful vasodilation, hypertensive action, and stimulation of extravascular smooth muscle. According to a previous report, it may have a potential apply in the field of onset and progressions of Alzheimer due to its similar activity and high level of sequence homology (73%) with b-amyloid protein fragments (Ab 25–35) and their analogs, which play a major role in the onset and progression of Alzheimer. recently, Eledoisin has been utilized to treatment the dry eyes successfully.
Pharmacokinetics and metabolism
The pharmacological and metabolism of eledoisin may not have been reported comprehensive and systematic. The reported pharmacological patterns of eledoisin that's not complicated may arise from a combined stimulation of receptors present on different cells in a tissue: NK-3 sites are only on postganglionic cholinergic neurons, NK-2 sites only on smooth muscle cells and NK-1 sites are located on these neurons and smooth muscle cells. It is worth to noticed that the eledoisin doesn't interact with lipid membranes in the presence of water. However, it assumed a β-structure when forced into contact with phosphatidylcholine membranes, perhaps the result of peptide aggregation.
References:
1. Grace, R. C. R., Chandrashekar, I. R., & Cowsik, S. M. (2003). Solution structure of the tachykinin peptide eledoisin. Biophysical journal, 84(1), 655-664.
2. Sanz-Nebot, V., Toro, I., & Barbosa, J. (1999). Fractionation and characterization of a crude peptide mixture from the synthesis of eledoisin by liquid chromatography-electrospray ionization mass spectrometry. Journal of Chromatography A, 846(1-2), 25-38.
3. Lippe, C., Bellantuono, V., Ardizzone, C., & Cassano, G. (2004). Eledoisin and Kassinin, but not Enterokassinin, stimulate ion transport in frog skin. Peptides, 25(11), 1971-1975.
4. Nebbioso, M., Evangelista, M., Librando, A., Plateroti, A. M., & Pescosolido, N. (2013). Iatrogenic dry eye disease: an eledoisin/carnitine and osmolyte drops study. Biomedicine & Pharmacotherapy, 67(7), 659-663.
5. Wilson, J. C., Nielsen, K. J., McLeish, M. J., & Craik, D. J. (1994). A determination of the solution conformation of the nonmammalian tachykinin eledoisin by NMR and CD spectroscopy. Biochemistry, 33(22), 6802-6811.
6. Schwyzer, R. (1987). Membrane-assisted molecular mechanism of neurokinin receptor subtype selection. The EMBO journal, 6(8), 2255-2259.
