Fig. 1: Sweetened oil emulsions and training improve voluntary drug consumption.
a, Adult male and female mice were trained for 3 days to consume 80 μl of formulations from a disposable plastic micropipette tip and on the fourth day were offered the same formulation containing TAM. b, Feeding time was recorded and considered voluntary if the mouse, held only slightly by the proximal tail section, drank the offered volume in less than 60 s. c, Any formulation not consumed after 60 s was offered again after gently restraining the mice by the scruff, and the extra time required to drink the remaining solution was recorded. d, The fraction of mice that voluntarily consumed (<60 s) oil (n = 21), sweetened MOE (n = 52) or SOE (n = 33) during 3 days of training (green bars) or TAM-containing formulations on the fourth day. Yellow bar, OIL-TAM (n = 12); blue bar, MOE-TAM (n = 17); orange bar, SOE-TAM (n = 17). The oil used for the formulations in d was sterilized by heat treatment. e, Total consumption time for three training days, recorded from the moment the MOE or SOE formulation was offered (n = 13 per group). Indicated is the time before restraining (white zone) as described in b and after restraining (red zone) as described in c. The oil used for the emulsions in e was sterilized by filtration. Minimum and maximum values, interquartile range and median are depicted as Tukey box plots with individual data points shown as gray circles.
