Effect of dynamic compression and pharmacological agents that influence the natriuretic peptide receptor 2 (Npr2) or Npr3 pathways. Absolute values for nitric oxide (NO) release (A), prostaglandin E2 (PGE2) production (B), glycosaminoglycan (GAG) synthesis (C) and total 3,5-cyclic guanosine monophosphate (cGMP) content (D). Chondrocyte/agarose constructs were cultured in the presence and absence of 0 or 10 ng/ml IL-1β and/or 100 nM C-type natriuretic peptide CNP or 0.5 μM P19 or 1 μM cANF4-23 for 48 hours. Error bars represent the mean and standard error of the mean (SEM) values of between eight and thirteen replicates from four separate experiments. In addition, the corresponding normalised strained values, presented as a percentage change of the unstrained controls, with SEM values are shown in brackets. Asterisks indicate significant comparisons in unstrained (black bars) and strained (white bars) constructs for the multiple treatment conditions. All other comparisons (not indicated) were not significant.