Ranakinin: a novel NK1 tachykinin receptor agonist isolated with neurokinin B from the brain of the frog Rana ridibunda.
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 immunoreactivity, measured with an antiserum directed against the NH2-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-NH2. 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-NH2. This amino acid sequence is the same as that of mammalian neurokinin B. Ranakinin was equipotent with substance P and [Sar9,Met(O2)11]substance P in inhibiting the binding of 125I-Bolton-Hunter-[Sar9,Met(O2)11]substance P, a selective radioligand for the NK1 receptor, to binding sites in rat submandibular gland membranes (IC50 1.6 +/- 0.3 nM; n = 5). It is concluded that ranakinin is a preferred agonist for the mammalian NK1 tachykinin receptor subtype.
O'Harte
F
F
Department of Biomedical Sciences, Creighton University Medical School, Omaha, Nebraska 68178.
Burcher
E
E
Lovas
S
S
Smith
D D
DD
Vaudry
H
H
Conlon
J M
JM
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D008969:Molecular Sequence Data; D015287:Neurokinin B / Q000302:isolation & purification*; D009842:Oligopeptides / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D011863:Radioimmunoassay; D011895:Rana ridibunda / Q000378:metabolism*; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D018039:Receptors, Tachykinin
D000596:Amino Acids; D009842:Oligopeptides; D017981:Receptors, Neurotransmitter; D018039:Receptors, Tachykinin; C071642:ranakinin; D015287:Neurokinin B