Myoview 2 software

Morphological properties of MAs from NT rats and SHRs as well as NT MAs treated with NTC miR or miR153 were studied using Pressure Servo System PS/200 (Living Systems Instrumentations, Burlington, VT, USA). The structural properties of the segments and responses to the Kv7 activator, S1 (NeuroSearch A/S, Ballerup, Denmark) were recorded and acquired with DMK 41AU02 Monochrome Industrial Camera (Imaging Source, Bremen, Germany) hosted by a PC running MyoVIEW II software (Danish Myo Technology, Aarhus, Denmark). Data were analysed using MyoVIEW II and MicroCal Origin 6.0 (MicroCal Software, Northampton, MA, USA). Isometric tension was recorded on NT MAs or MCAs transfected with either mir153 or NTC miR in a wire myograph (Danish Myo Technology). Mesenteric vessels were pre-constricted with 1 µM U46619 (Sigma Aldrich) and a concentration effect curve to the Kv7.2–7.5 activators ML213 (HelloBio, Bristol, UK), ICA-069673 (HelloBio), the β-adrenoceptor agonist isoprenaline (Sigma Aldrich), or the Kv7.1-specific activator RL-3 (Tocris, Bristol, UK) as well as a relaxation response to 1 µM nicardipine (Sigma Aldrich) were obtained. Relaxant responses to S1 or ML213 were also assessed in MCAs transfected with miR153 or NTC and pre-constricted with 100 nM U46619. Data were recorded and analysed using LabChart® 7 (ADInstruments, Dunedin, New Zealand).

Descending aortas were mounted on steel cannulas (outer diameter‐size range between 400 and 1,200 µm) in a pressure myography system (110P‐DMT‐USA Inc., Danish Myo Technology). An inverted microscope (Leica DMI 6000) equipped with a charge couple device camera was used to visualize the vessels. MyoView II software (Danish MyoTechnology) was used to monitor inside and outside diameters and to record the data. All surrounding fat tissue was removed from the aortas and the aortas were placed on the pressure myograph chamber. After the first cannula was mounted, aortas were cleaned and perfused with HEPES‐buffered Krebs solution containing 2.5 mM CaCl₂. The vessels were allowed to equilibrate at 45 mmHg and 37°C for 1/2 hr before testing. To examine distensibility, the intraluminal pressure was raised from 5 to 170 mmHg in 10 mmHg increments with a constant temperature at 37°C. The bath solution was changed between samples. The pressure was maintained for 5 min at each step and vessel characterization data were recorded at the end of this time. Distensibility was estimated under relaxed conditions by determining changes in outer diameter size as a function of pressure normalized to the diameter at 5 mmHg.