Identification and characterization of multiple tachykinin immunoreactivities in bovine retina: evidence for the presence of a putative oxidative inactivation system for substance P

J Neurochem. 1989 Nov;53(5):1547-54. doi: 10.1111/j.1471-4159.1989.tb08551.x.


Tachykinin immunoreactivity has been quantified and characterized in extracts of bovine retinae by combining radioimmunoassay, gel permeation chromatography, and reverse-phase HPLC. Using an antiserum specific for the C-terminal hexapeptide amide of substance P, levels of 3.43 +/- 0.33 ng g-1 and 12.45 +/- 0.76 ng g-1 (mean +/- SD, n = 5) were measured in extracts prepared by acidified ethanol and boiling 0.5 M acetic acid, respectively. Levels of neurokinin A immunoreactivity, assayed using an antiserum cross-reacting with neurokinin A (100%), neurokinin B (50%), neuropeptide K (85%), and substance P (less than 0.1%) were 12.46 +/- 0.47 ng g-1 and 7.20 +/- 0.37 ng g-1 in the same extracts. Gel permeation chromatography identified a single substance P immunoreactant eluting with substance P standard, whereas two neurokinin A immunoreactants were resolved eluting with neuropeptide K and neurokinin A standards. Reverse-phase HPLC analysis resolved immunoreactivity eluting with substance P, neurokinin A, neuropeptide K, and neurokinin B and their respective methionine sulphoxides. The amount of immunoreactive material co-eluting with the respective sulphoxides was higher in acidified ethanol extracts, and substance P was most susceptible to oxidative modification. Subsequent incubation of synthetic substance P with dispersed bovine retinal cells resulted in rapid conversion to three metabolites identified and isolated by reverse-phase HPLC. Each had an amino acid composition identical to that of substance P, and the major product had the same retention time as substance P sulphoxide.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amides / metabolism
  • Amino Acids / metabolism
  • Animals
  • Cattle
  • Chromatography, Gel
  • Chromatography, High Pressure Liquid / methods
  • Oxidation-Reduction
  • Radioimmunoassay
  • Retina / metabolism*
  • Substance P / metabolism*
  • Tachykinins / analysis*


  • Amides
  • Amino Acids
  • Tachykinins
  • Substance P