EFFECTS OF ADJUVANT ON NEUROPEPTIDE-LIKE IMMUNOREACTIVITY IN EXPERIMENTALLY-INDUCED TEMPOROMANDIBULAR ARTHRITIS IN RATS

Substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptid e (CGRP)- and neuropeptide Y (NPY)-like immunoreactivities (-L1) were examined in cerebrospinal fluid (CSF), plasma and temporomandibular jo int (TMJ) perfusates in rats 1 and 12 h after inoculation at the base of the tail (0.05 mi) or injection into the right TMJ (0.01 mi) of hea t-killed Mycobacterium butyricum in paraffin oil. In the rats inoculat ed at the base of the tail (polyarthritic rats), there was a significa nt increase of CGRP-LI and NKA-LI. The changes in neuropeptide-LI were not as marked in the CSF of rats injected with adjuvant in one TMJ (m onoarthritic rats) as in the polyarthritic group. Instead, the most si gnificant changes in the monoarthritic rats were seen in the perfusate s of both TMJs. The increases in SP-, NKA-, CGRP- and NPY-LI were sign ificant for both TMJs and more pronounced than in the polyarthritic ra ts. The results show that inoculation of adjuvant at the base of the t ail induces significant changes of neuropeptide-LI predominantly in CS F, whilst an intra-articular injection induces bilateral changes in ne uropeptide-LI. in joint perfusate. Therefore, two different neural mec hanisms may be involved early in adjuvant-induced poly- and monoarthri tis. Copyright (C) 1996 Elsevier Science Ltd.