THE EFFECT OF A SINGLE INTRAPERITONEAL DOSE OF HRIL-1-ALPHA ON SUBSTANCE-P, NEUROKININ-A, CALCITONIN-GENE-RELATED PEPTIDE AND NEUROPEPTIDE-Y-LIKE IMMUNOREACTIVITY IN CEREBROSPINAL-FLUID, PLASMA AND KNEE-JOINT SYNOVIAL-FLUID IN THE RAT

Substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivity (-LI) was studied in rats' cerebrospinal fluid (CSF), plasma and synovial fluid (SF) from both knee joints at 2 and 24 h following an intraperitoneal administration of 0.05 mi human recombinant interleukin-lu (i.p. hrIL-1 alpha) or saline. Increased or decreased levels of SP-, NKA and CGRP-LI were detected in CSF and plasma, whereas NPY-LI was unaffected. In SF only CGRP-LI increased bilaterally. There was a correlation in CGRP-LI content between plasma and CSF following i.p. hrIL-1 alpha but not between plasma and SF or CSF and SF. It can be concluded that (I)i.p. hrIL-1 alpha activates somatosensory afferents thereby increasing SP- and CGRP-LI content in CSF and plasma and NKA-LI in CSF; 2) i.p. hrIL-1 alpha induces a bilateral increase of CGRP-LI in SF which is not mediated through systemic circulation and is possibly a part of the general host defensive reaction.