Serotonin in an antigen-induced arthritis of the rabbit temporomandibular joint.

The aim was to investigate the joint perfusate concentration of serotonin (5-HT) in antigen-induced monoarthritis of the rabbit temporomandibular joint (TMJ) and knee joint. Thirty adult male New Zealand White rabbits, of whom eight were first used as healthy controls, were divided into TMJ and knee arthritis groups. Unilateral arthritis was induced with ovalbumin intra-articularly and the contralateral joint was sham-induced. The joints were perfused with saline (flow rate, 0.05 ml/min; 10-min intervals during 50 min) 3 weeks later and the 5-HT concentration analysed. After the perfusion, the joints were evaluated histologically. The 5-HT concentration in the initial perfusate from the arthritic TMJ was higher than in both sham-induced and healthy control joints, and from the knee joint arthritis higher than in sham-induced joints. No histological difference in the arthritis was observed between the two groups. This study shows that the 5-HT concentration found immediately after puncture is increased in antigen-induced arthritis of the rabbit TMJ and knee joint.