Collagenase synthesis of rheumatoid arthritis synoviocytes: dose-dependent stimulation by substance P and capsaicin.

The synthesis and release of collagenase in the presence of the neuropeptide substance P (SP) and capsaicin, were investigated in vitro using identical synoviocyte cultures from patients with rheumatoid arthritis (RA). On average 10(-12) M SP augmented statistically significantly the collagenase production by approximately a factor of five. An increase in the concentrations up to 10(-6) M SP resulted in a decreased collagenase synthesis, which, however, was still above the level of that of the untreated synoviocytes. Capsaicin, a homovanillic acid derivative that acts as a releaser of SP from primary afferent neurons, caused a strong stimulation of collagenase production and release at 10(-8) and 10(-6) M (about 7 times the amount of the control). With increasing concentrations up to 10(-3) M capsaicin this effect diminished continuously. The experiments clearly show that in RA synoviocytes in vitro SP and capsaicin in low concentrations act as potent inducers of the synthesis and release of collagenase.