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Ranakinin: A Novel NK1 Tachykinin Receptor Agonist Isolated with Neurokinin B from the Brain of the Frog Rana ridibunda
Author(s) -
O'Harte Finbarr,
Burcher Elizabeth,
Lovas Sandor,
Smith D. David,
Vaudry Hubert,
Conlon J. Michael
Publication year - 1991
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1991.tb06426.x
Subject(s) - substance p , neurokinin b , tachykinin receptor , neurokinin a , agonist , receptor , medicine , endocrinology , chemistry , peptide , eledoisin , biology , neuropeptide , biochemistry
An extract of the whole brain of the frog Rana ridibunda contained high concentrations of substance P‐like immunoreactivity, measured with an antiserum directed against the COOH‐terminal region of mammalian substance p and neurokinin b ‐like immurtoreactivity, measured with an antiserum directed against the NH 2 ‐terminus of neurokinin B. The primary structure of the substance p ‐related peptide (ranakinin) was established as: Lys‐Pro‐Asn‐Pro‐Glu‐Arg‐Phe‐Tyr‐Gly‐Leu‐Met‐NH 2 . Mammalian substance P was not present in the extract. The primary structure of the neurokinin b ‐related peptide was established as: Asp‐Met‐His‐Asp‐Phe‐Phe‐Val‐Gly‐Leu‐Met‐NH 2 . This amino acid sequence is the same as that of mammalian neurokinin B. Ranakinin was equipotent with substance p and [Sar 9 ,‐Met(O 2 ) 11 ]substance p in inhibiting the binding of 125 I‐Bolton‐Hunter‐[Sar 9 , Met(O 2 ) 11 ]substance p , a selective radio‐ligand for the NK1 receptor, to binding sites in rat subman‐dibular gland membranes (IC 50 1.6 ± 0.3 n M ; n = 5). It is concluded that ranakinin is a preferred agonist for the mammalian NK1 tachykinin receptor subtype.