What are the ways to calculate rate and concentration of noradrenaline?
Two samples were collected for each frequency, resulting in a 12 total. Scintillation counting of the samples was conducted at the end of the experiment. The tissue slices were homogenized. 1 mL of sample collected in Kreb’s solution was added to 10 mL of scintillation fluid, and this was then placed on the scintillation counter. Basal efflux was calculated by dividing the count for an unstimulated tissue by the mass of the tissue (mg), giving a value of concentration. To calculate the rate, the concentration was then divided by the time in minutes. These values were plotted graphically (CPM/mg/min vs. time), and rate values were determined at the following time intervals: 6, 12, 18, 24, 30, and 36 minutes. Concentrations were then calculated for samples during and after stimulation; the count for each tube (CPM) was divided by the mass of the tissue (mg). The rate of noradrenaline release was then calculated. For samples collected during the stimulation, the concentration was divided by the duration of stimulation time (minutes). For samples collected after stimulation, the concentration was divided by the duration of rest time. Next, the 3H-Noradrenaline released by electrical stimulation alone was calculated by subtracting the value for rate after stimulation from the value for rate during stimulation. Finally, the percent release of 3H-Noradrenaline was calculated by dividing the previous value by the basal efflux rate value (determined earlier graphically). This ratio was then multiplied by 100 to yield a percentage.