Original source: Article Cardiac morphology and blood pressure in the adult zebrafish

Hemodynamic Measurement Zebrafish were anesthetized with tricaine methanesulfonate (MS222) at a dose of 0.40 g/kg in 0.075 g/L instant ocean solution (Hu et al., 2000) and transferred to a shallow concave trough of a custom-built glass chamber (Radnoti, Monrovia, CA). The trough was filled with instant ocean solution, and the temperature of the solution was monitored by a thermistor and maintained by 15 L/min flow of 30°C water through the hollow wall of the glass chamber. We measured the pressures in the atrium, ventricle, dorsal, and ventral aorta of the adult zebrafish with a model 900A servonull pressure system (World Precision Instruments, Sarasota, FL). The probe was a 5-mm diameter tip glass micropipette filled with 1 M NaCl. The cannula was zeroed at the level of the heart before and after pressure measurements. The servonull measured pressure is linear (y 5 0.995x 2 0.23) and highly correlated (r 5 0.99, S.E.E. 5 0.11 mmHg) when compared with a standing water column over the range of 0 to 30 mmHg (Clark and Hu, 1982, 1990; Hu and Clark, 1989). Analog pressure waveforms were digitally sampled at 2-msec intervals by an analog to digital conversion board (LabView, National Instruments, Austin, TX) and stored for processing on Jaz cartridges (Iomega, Roy, UT). Ventricular dP/dt was mathematically derived with the analysis software. At least five consecutive cycles were analyzed for each measurement. Quantitative data (n $ 5) are presented as mean 6 standard error of the mean, and analyzed by Student’s t test, with statistically significant differences defined as a P-value of less than 5%.

yes, you can measure the osmosis pressure

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