Figure 4. Bone formation decreases in the absence of 5-HT_2BR.

Static and dynamic bone parameters and biochemical markers were measured in 4- and 18-month-old 5-HT_2BR^−/− (open bars) and WT female mice (black bars). Representative tetracycline/calcein double-labeling in 4-month-old 5-HT_2BR^−/− and WT bone sections are shown (A). Dynamic formation parameters (mineralizing surface/bone surface = MS/BS) (B), mineralizing apposition rate = MAR) (C) and bone formation rate = BFR) (D), as well, as biochemical markers of bone resorption (urinary deoxypyridinoline cross-links = Dpd) (E), biochemical markers of bone formation, plasma alkaline phosphatase activity = ALP activity) (F) and plasma osteocalcin level (G) were determined. Data are shown as means ± SEM (n=10–12 sections per sample). Asterisks indicate significant difference between genotypes (* = P < 0.05, ** = P < 0.01, *** = P < 0.001).