Aliquots of the platelet suspension are withdrawn before and at various times after addition of spermine NONOate or Cinaciguat and transferred immediately into inactivation buffer (50 mM Tris, 4 mM EDTA, pH 7.4) at 100°C for at least 10 min. When used, 10 μM ODQ is added to the platelets 15 min before addition of spermine NONOate. Purified GC activity is measured at a final concentration of 50 ng/mL in assay buffer (50 mM Tris, 100 μM EDTA, 1 mM NaGTP, 1.3 mM MgCl₂, 50 μg/mL BSA, pH 7.4), stimulated with DEA/NO (10 μM) or Cinaciguat (1 μM), enzyme inactivation being performed as with platelets. The levels of cGMP are measured by radioimmunoassay and expressed relative to the amount of protein. Three independent runs are carried out in each experiment and the resulting data presented as means±s.e.mean^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Mice^[2]
Male and female mice (12 weeks old) are anaesthetized with isoflurane, 0.5 cm of the tail tip is removed with a sharp razor blade, and the tail tip is immediately put into fresh pre-warmed PBS of 37°C. The latency until the tail stopped bleeding is visually scored and recorded with a chronometer by an observer blinded to the genotype. Systolic BP (SBP) and heart rate (HR) are measured non-invasively in awake mice by tail-cuff using a Hatteras MC4000 Blood Pressure Analysis System. Mice are habituated to the BP measurement device for 7 days. To determine basal BP, mice are measured for 15 consecutive cycles per day during 5 days. L-NAME (100 mg/kg), SNP (1.5 mg/kg), DETA-NO (60 mg/kg), BAY 41-2772 (4 mg/kg), Cinaciguat (30 μg/kg) and the vehicle controls (PBS or for the BAY-compounds 20% Cremophor+20% diethylene-glycol-monoethyl-ether in PBS) are all administered IP. After SNP administration, SBP measurements are recorded from 5 to 15 min post injection, for L-NAME and DETA-NO recordings are made from 1 to 25 min post injection and for BAY-compounds recordings are made from 10 to 25 min post injection.

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. Roy B, et al. Probing the presence of the ligand-binding haem in cellular nitric oxide receptors. Br J Pharmacol. 2008 Apr;153(7):1495-504.  [Content Brief]

  [2]. Thoonen R, et al. Cardiovascular and pharmacological implications of haem-deficient NO-unresponsive soluble guanylate cyclase knock-in mice. Nat Commun. 2015 Oct 7;6:8482.  [Content Brief]