Cell experiment:

Confluent chondrocytes are incubated for 24 h with SP or Substance P (7-11). TIMP activity is inactivated following reduction and alkylation with 2 mM dithiothreitol and 5 mM iodoacetamide for 30 min at 37℃. Samples are subsequently dialysed. Latent collagenase is activated with 1 mM APt followed by inactivation with soy bean trypsin inhibitor. Collagenase is measured[1].

Substance P (7-11) is a C-terminal fragment of Substance P which can cause an increase in the intracellular calcium concentration.

Substance P (7-11) increases PGE2 and collagenase production at concentrations greater than 1 μM. Substance P (7-11), but not intact SP, SP-(1-4), SP-(1-6), SP- (8-11) or SP-(9-1 1), nor the tachykinins NKA and NKB, causes an increase in the intracellular calcium concentration as measured by the fluorescent dye Fura-2. The maximal change in intracellular calcium induced by 10 μM Substance P (7-11) was 140±30 nM[1].

[1]. Halliday DA, et al. The substance P fragment SP-(7-11) increases prostaglandin E2, intracellular Ca2+ and collagenase production in bovine articular chondrocytes. Biochem J. 1993 May 15;292 ( Pt 1):57-62.