Substance P-, neurokinin A-, calcitonin gene-related peptide- and neuropeptide Y-like immunoreactivity (-LI) in rat knee joint synovial fluid during acute monoarthritis is not correlated with concentrations of neuropeptide-LI in cerebrospinal fluid and plasma.
In a recent study we have shown a bilateral release of substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivity (-LI) in rat synovial fluid during acute monoarthritis. In order to elucidate the mechanisms underlying these phenomena, we examined the correlation between neuropeptide-LI in rat cerebrospinal fluid (CSF) and synovial fluid and between plasma and synovial fluid following the intra-articular injection of equal volumes (0.05 ml) of either Freund's adjuvans, carrageenan 2%, substance P 10(-5) M or human recombinant interleukin-1 alpha. Control rats were given saline intra-articularly. CSF, plasma and synovial fluid from the knee joints were obtained at 2, 6 and 24 h after injection and were analysed by specific radioimmunoassays. The intra-articular injection of pro-inflammatory substances induced changes in neuropeptide-LI in synovial fluid, CSF and plasma. However, there was no correlation between neuropeptide-LI in synovial fluid and plasma or between synovial fluid and CSF. The results of the present study does not support the hypothesis that the bilateral changes in neuropeptide-LI in synovial fluid were due to a release of neuropeptides from the inflamed joint into the systemic circulation. However, in carrageenan induced inflammation there was a tendency towards a correlation in SP-LI between CSF and synovial fluid suggesting that central neurogenic mechanisms should be studied in order to explain the bilateral changes seen.
Bileviciute
I
I
Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
Lundeberg
T
T
Ekblom
A
A
Theodorsson
E
E
D000208:Acute Disease; D000818:Animals; D001168:Arthritis / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D007719:Knee Joint / Q000378:metabolism*; D008297:Male; D015288:Neurokinin A / Q000378:metabolism; D009478:Neuropeptide Y / Q000378:metabolism; D009479:Neuropeptides / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*; D009994:Osmolar Concentration; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D013373:Substance P / Q000378:metabolism; D013582:Synovial Fluid / Q000378:metabolism*
D009478:Neuropeptide Y; D009479:Neuropeptides; D013373:Substance P; D015288:Neurokinin A; D015740:Calcitonin Gene-Related Peptide