The expression of NK₁-receptor in the osteoblasts and the effects of tachykinins on the bone formation

Abstract

The aim of this study is to investigate the expression of NK₁-receptors in osteoblasts and the effects of tachykinins (substance P, neurokinin A, and neurokinin B) on bone formation by rat calvarial osteoblasts. NK₁-receptor mRNA expression and fluo-SP binding were found in 16-day cultured osteoblats. A significant increase in bone formation by cultured osteoblasts was observed with the addition of 10^-7-10^-6M SP or 10^-11∼10^-9M NKB, but not NKA. These increases in bone formation with the addition of SP or NKB were inhibited by the addition of SP or NK₁-R antagonists. The results indicate that SP and NKB stimulate bone formation by osteoblasts at the late stage of bone formation via NK₁-Rs.