Abstract
N-terminally extended substance P (SP) and neuropeptide K (NPK), an N-terminally extended form of neurokinin A (NKA), were determined in cerebrospinal fluid (CSF) from healthy human subjects by combined high performance liquid chromatography and radioimmunoassay. The concentrations of the peptides were similar in fresh CSF and in CSF which had been kept frozen for up to 5 months. SP and NKA were not present in measurable amounts in neither fresh CSF nor in CSF that had been frozen. On the other hand, when synthetic SP and NKA were added to approx. 2 pM concentration to fresh CSF samples, both peptides were recovered to 85 and 98%, respectively. There were no significant concentration gradients of the peptides in the first 18 ml (three consecutive 6 ml fractions) of CSF (n = 10). In contrast, we confirmed previous findings, that there are gradients of the amine metabolites 5-HIAA (P < 0.01) and HVA (P < 0.001) (n = 5). The concentrations of extended SP (expressed in SP equivalents) and NPK in the first 6 ml of CSF were 1.5 +/- 0.7 pM and 14.2 +/- 6.4 pM (mean +/- S.D., n = 10), respectively. The present results thus show that the levels of N-terminally extended SP and NKA are stable in frozen CSF samples for up to 5 months. The virtual lack of SP and NKA in CSF does not seem to be due to losses during sample preparation or storage.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.