Mice were assessed for:
Construction of drinking tubes and other experimental procedures are given in detail at www.monell.org/MMTPP. Each drinking tube consisted of a 25-ml plastic serological pipette with 0.2 ml gradations (Fisher cat no. 13-678-14B). This was connected to a 63.5-mm long stainless steel straight sipper tube (Unifab, Cat. No. US-171-25) with a 15-mm piece of silicon tubing (Cole Palmer, Cat. No. 06411-76). The top of the pipette was closed with a size 00 rubber stopper. Tubes were always given in pairs, with one containing deionized water and the other taste solution. The drinking tubes were placed to the (experimenter's) left of the food hopper. The spouts extended ~25 mm into the mouse cage and their tips were ~20 mm apart. Each spout had a tip with a 3.175-mm diameter hole from which the mice could lick fluids.
After 6-10 days habituation to laboratory conditions, the mice were tested with the following compounds in the order listed.
Compounds were purchased from Sigma-Aldrich, and were prepared in deionized water. The "water" drinking tube also contained deionized water. Each test was 48 h in duration and the positions of the two drinking tubes were switched after 24 h to control for side preferences. Intakes were measured to the nearest 0.1 ml at the end of each test. Extensive experience has shown that fluid spillage and evaporation is ~0.25 ml over 48 h with these procedures, and so these were ignored.
All measurements were made in the middle of the light period (late morning or early afternoon). Body weight was measured (to the nearest 0.1 g) at the beginning and end of the 24-day test series.
Data available include preference scores for three concentrations of each solution.
Notes: A few (94 out of 37,920) measurements were lost due to
spilled or blocked drinking tubes, or other technical problems.
When intake was compromised, the mouse was retested at the end of
the series. The results of these retests are included in the
submitted data set. Retested mice (per
measurement) are disclosed at
Bone and Body CompositionAt least 6 days after the tail blood sample was collected, each mouse was anesthetized with 70 mg/kg ketamine + 10 mg/kg xylazine (5 ml/kg) and as much blood as possible (400 - 1400 uL) removed by cardiac puncture. The dead mouse was then wrapped in aluminum foil and frozen at -80°C for several months.
Frozen carcasses were allowed to thaw at room temperature for ~1 h, weighed using a top-loading balance, and then analyzed using a PIXImus II mouse densitometer (#51601; GE Medical Systems Lunar, Madison, WI). Each carcass was laid out on a plastic tray in the prone position with the limbs held splayed apart with tape. The tail was displaced to the mouse's left so that it was within the X-ray field but did not overlap a limb. Because the cone-beam X- ray field is only 80 x 65 mm and thus too small to fit a whole adult mouse, the head of each mouse was excluded from analysis; it was either placed outside the X-ray field or masked using software.
The PIXImus uses low energy X-rays to produce high-resolution (0.18 x 0.18 mm pixel) images of the mouse. PIXImus 2 2.0 software included with the machine calculates bone mineral density and content, and body fat and lean tissue content. The PIXImus was calibrated daily using a plastic "mouse phantom" provided by the manufacturer.
Data are available for:
BMC = BMD x bone area
% Fat = (Fat weight / Total weight) x 100
% Lean = (Lean weight / Total weight) x 100