F.B. Jolicoeur

Effects of acute and chronic administration of caffeine on schedule dependent and schedule induced behavior

The effects of caffeine (3.125, 6.25, 12.5, 25, 50, and 100 mg/kg) on lever pressing, schedule induced licking and water consumption induced by a fixed interval 1 min schedule were studied. Changes in these dependent variables were assessed when animals were reduced to 80% of their initial body weight by partial food deprivation and when body weights recovered after the animals were returned to conditions of ad lib feeding. Results indicate differential effects of the drug between animals at 80% body weight and when they are permitted to recover. Tolerance was examined for a single large dose only for the same dependent variables in animals at 80% body weight.

Effects of caffeine administration on food and water consumption under various experimental conditions

The effects of caffeine on food and water intake was assessed in rats maintained under several experimental conditions. In Experiment 1, caffeine, 3.125, 6.25, 12.5, 25.0, 50.0 or 100.0 mg/kg was injected into 23 hr food deprived, 23 hr water deprived or ad lib animals. In Experiment 2, animals were adapted to a 21 hr food deprivation schedule and administered the same doses of caffeine as were used in Experiment 1. Results indicate that caffeine both enhances and decreases food and water intake and that the effects observed depend on the experimental circumstances.

The effects of various barbiturates on LiCl induced taste aversion

The effects of various barbiturates on LiCl induced taste aversion were examined. Rats were adapted to a 23 hr and 50 min water deprivation schedule. On the Treatment Day, animals were offered a novel 0.125% saccharin solution and then administered 3.0 mEq/kg LiCl. The saccharin solution was presented again on three subsequent Test Days. Fifteen minutes prior to drinking on the first Test Day animals were injected subcutaneously with either 10, 30, and 50 mg/kg Amobarbital, 3, 9, and 15 mg/kg Pentobarbital, 40, 80, and 120 mg/kg Barbital, or 1, 3, and 9 mg/kg Hexobarbital. Results indicate that only 30 mg/kg of Amobarbital and 15 mg/kg of Pentobarbital significantly attenuated the magnitude of taste aversion.

Effects of phenobarbital on saccharin and citric acid intake in fluid deprived rats

Rats were adapted to a 23 hr fluid deprivation schedule. Every third day animals were offered either 0.125 percent Na saccharin or 0.2 percent citric acid solutions in place of water during the 1 hr drinking session. Sodium phenobarbital was administered subcutaneously, 40 mg/kg, 15 min prior to drinking. Results indicate that the drug increases saccharin and citric acid consumption following the injections. No decreases in intakes of saccharin and citric acid occurred on subsequent postdrug days and the amounts of fluid consumed on these days were comparable to the baseline predrug days intakes.

Effects of two body weight reduction regimens on schedule dependent and schedule induced behavior

Abstract Fifteen male hooded rats were divided into three equal groups on the basis of body weights. One group was allowed to eat ad lib and constituted the Control Group. The second group of animals was reduced over 7 days and adjusted to 80 percent of the body weight of the animals in the Control Group for a 23 day period and constituted the Adjusted Group. Animals in the third group were reduced to 80 percent of their own predeprivation body weight over 7 days and were maintained at this constant level for a 23 day period and constituted the Constant Group. The two experimental groups were then allowed to feed ad lib for the remainder of the experiment. Both the Adjusted and the Constant Groups were tested throughout restricted and ad lib eating periods on a FI 1 min food reinforcement generator schedule. Schedule dependent lever pressing, schedule induced licking and drinking, food intake and body weights were recorded for the duration of the experiment. Results demonstrate that schedule induced licking and drinking and schedule dependent lever pressing increased in the Constant Group at reduced body weight. Animals in the Adjusted Group did not change significantly on these measures during the same periods. When animals were returned to ad lib feeding conditions, the Constant Group initially increased body weight at a faster rate, ate significantly more, and exhibited significantly increased schedule induced licking and drinking. These initial differences disappeared later during the same period. The two experimental groups did not attain the expected body weight of the normal Control Group during 78 days of ad lib eating. Apparently, when animals are initially deprived rapidly and maintained at relatively constant body weight reduction, a prolonged body weight deficit occurs even though these same animals eat normal amounts of food.

Effects of methylphenidate on schedule dependent and schedule induced behavior

The effects of methylphenidate, 1.5, 3.0, 6.0 and 12.0 mg/kg, on lever pressing, schedule induced licking, and drinking were studied. The generator schedule was a fixed interval 1 min food reinforcement schedule. The effects were assessed when animals were reduced to 80% body weight by partial food deprivation and when allowed to recover body weight under conditions of ad lib eating. Results indicate that under body weight conditions methylphenidate significantly decreases schedule induced licking and drinking but does not affect lever pressing.

The effects of phenobarbital on lithium chloride induced taste aversion.

The dose related effects of phenobarbital on LiCl induced taste aversion were examined. Rats were adapted to a 23 hr 50 min water deprivation schedule. On the Treatment Day animals were offered a novel 0.125% saccharin solution during the 10 min drinking session and were then administered 3.0 mEq/kg LiCl. The saccharin solution was presented again on six subsequent Test Days. Sodium phenobarbital 20, 40, 60 and 80 mg/kg was administered 15 min prior to drinking on the first Test Day. Results indicated that all doses significantly attenuated taste aversion with the maximal effect occurring with the 60 mg/kg dose.

Effects of phenobarbital on taste aversion induced by x-radiation

The effects of phenobarbital on taste aversion induced by X-radiation were examined. Rats were adapted to a 23 hr 50 min water deprivation schedule. On the Treatment Day animals were given a novel 0.125% Na saccharin solution during the 10 min drinking session and were then exposed to 100 rads of X-radiation. The saccharin solution was presented again on six subsequent Test Days. Phenobarbital in doses of 20, 40, 60 and 80 mg/kg was administered 15 min prior to drinking on the first Test Day. Results demonstrate that phenobarbital in all doses tested has a significant attenuating effect on radiation induced taste aversion.

Effects of glucose and saccharin solutions on subsequent food consumption

Abstract Twenty three hr water deprived animals were given access to various glucose and glucose + saccharin solutions during a 1 hr drinking session. Subsequent 1 hr and 22 hr food intakes were measured. Results indicate that more food was consumed during the first post drinking hour by the animals when receiving 3.5% GLU + 0.25% SACC while comparatively less food was consumed by them following the ingestion of 21% GLU and 21% GLU + 0.25% SACC. During the remaining 22 hr when the animals received 21% GLU and 21% GLU + 0.25% SACC they increased their food intake such that total 23 hr food intake was unaffected. Food intake was not related to the amounts of the different fluids consumed but appeared to be determined by other oral and post ingestion factors associated with the different solutions.

Effects of ethyl alcohol on forced consumption of an acclimated saline solution

Forced consumption of a 1.7% sodium chloride solution was determined in 3 groups of male hooded rats, 4 in each group, over a period of 115 days. A control group received 1.7% NaCl for the duration of the experiment. An ethyl alcohol experimental group received gradually increasing concentrations of ethyl alcohol, 0.5 to 6.0%, in the 1.7% NaCl drinking fluid for 30 days. For the next 25 days 6% ethanol was mixed with the 1.7% sodium chloride solution. A second experimental group was treated similarly except that varying concentrations of citric acid were added to the saline drinking fluid in place of the ethyl alcohol. At the end of the 55 day period, the ethyl alcohol and citric acid were removed from the drinking fluid of both groups. Dramatic and copious amounts of drinking occurred only in the group which had previously drunk the ethyl alcohol. Since excessive drinking of the 1.7% sodium chloride solution did not occur in the other experimental group when the citric acid was removed, the copious drinking can be attributed specifically to the prolonged ingestion and withdrawal of the ethyl alcohol. Possible significance to an animal model for alcoholism is discussed.