The effect of phenobarbital dose upon a variety of drinking related response measures.

Amount of water ingested, total laps, duration of drinking, amount per lap, laps per minute, and running velocity were investigated as a function of phenobarbital dosage (0 to 60 mg/kg). Twenty-three and a half (23 1/2) hour water deprived females rats served in the experiment. Amount of water ingested, total laps, and duration of drinking all responded similarly to phenobarbital all rose and subsequently fell as a function of phenobarbital dose on the day of drug treatment, rose as a linear function of dose a day later, and had no significant relation with dose 2 days after drug administration. These measures significantly intercorrelate with each other on the day of drug treatment and the day thereafter though not 2 days thereafter. Running velocity largely declines as a function of drug dosage on the day of treatment but is unaffected by the drug thereafter. The other measures show no definite trend. However these measures, running velocity and amount/lap and laps/minute, intercorrelate significantly with each other on the day of treatment and not thereafter. The first group of response measures and the latter group do not consistently correlate with each other. It was concluded that there are two identifiable classes of variables: one motor, which is largely a decremental function of dose, the other uncharacterized, initially rising, then falling as a function of phenobarbital dose on the day of drug treatment.