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Biomedical subjects

R W Foltin

Publications and source records attributed to R W Foltin.

At least 127 records · Page 7Linked to original sources
PubMed1988

Effects of smoked marijuana on human social behavior in small groups.

Six adult male research volunteers, in two groups of three subjects each, lived continuously in a residential laboratory for seven consecutive days. Subjects' behaviors, including social interaction and coaction, were continuously recorded. During the first part of the day (0945-1700), subjects remained in their private rooms doing work activities. During the remainder of the day (1700-2345), they had the option to socialize with the other subjects. Four cigarettes containing active marijuana (2.7% delta 9-THC w/w) or placebo were smoked daily: two during the work period, and two during the social access period. Active marijuana had no effect on the total amount of time that subjects spent in the social area. However, active marijuana changed the distribution of activity within the social area by decreasing the amount of time subjects spent engaging in verbal exchanges, i.e., interaction, while simultaneously increasing the amount of time that subjects engaged in the same activity, but in the absence of verbal exchanges, i.e., coaction.

Adult↗
PubMed1988

Repeated intranasal cocaine administration: lack of tolerance to pressor effects.

Three healthy adult male volunteers were allowed to self-administer 96 mg or 4 mg (a dose without measurable effects) of inhaled cocaine approximately once every 35 min during experimental sessions lasting up to 6 h. Heart rate (HR), blood pressure and self-report of drug effects were measured. After inhaling, on average, four doses of 4 mg, subjects voluntarily ended the session. Five out of the six sessions of 96 mg cocaine availability, however, were terminated due to consistent elevated diastolic blood pressure (DP), rather than by subject request. During 96 mg sessions, HR and self-report data either rapidly reached an asymptote or showed a slow rate of increase. Blood pressure, on the other hand, increased throughout the session, generally to the point where the session had to be terminated. These findings suggest the possibility that the rate of development of tolerance to the effects of cocaine may vary as a function of the dependent variable. In addition, the consistent increase in pressor effects may well be a mechanism for the increased cardiovascular toxicity reported for cocaine abusers.

Administration, Intranasal↗
PubMed1988

Effects of marijuana on the task-elicited physiological response.

Ten healthy male marijuana users smoked either a placebo or active (1.8% delta 9-THC) marijuana cigarette during five daily testing sessions. Ten minutes after drug administration, six subjects (Group I) performed a 10-min serial acquisition task and four subjects (Group II) rested quietly. Blood pressure was sampled at 2-min intervals and heart rate (HR) was recorded continuously. Marijuana alone increased HR by 18 beats/min and mean arterial pressure (MAP) by 3 mmHg, while task performance alone increased HR by 4 beats/min and MAP by 5 mmHg. The combination of drug and task performance had greater cardiovascular effects than either task performance or marijuana alone, with HR increased by 29 beats/min and MAP increased by 15 mmHg. These results suggest that marijuana smoking may increase cardiovascular responsivity.

Adult↗
PubMed1988

Effects of smoked marijuana on food intake and body weight of humans living in a residential laboratory.

Six adult male research volunteers, in two groups of three subjects each, lived in a residential laboratory for 13 days. All contact with the experimenter was through a networked computer system and subjects' behaviors, including food intake, were continuously recorded. During the first part of the day, subjects remained in continuously recorded. During the first part of the day, subjects remained in their private rooms doing planned work activities, and during the remainder of the day, they were allowed to socialize. Two cigarettes containing active marijuana (2.3% delta 9 THC) or placebo were smoked during both the private work period and the period of access to social activities. Smoked active marijuana significantly increased total daily caloric intake by 40%. Increased food intake was evident during both private and social periods. The increase in caloric intake was due to an increased consumption of snack foods as a consequence of an increase in the number of snacking occasions. There was no significant change in caloric consumption during meals. The principal increase within the category of snack foods was in the intake of sweet solid items, e.g., candy bars, compared to sweet fluid, e.g., soda, or savory solid items, e.g., potato chips. Increases in body weight during periods of active marijuana smoking were greater than predicted by caloric intake alone.

Adult↗
PubMed1988

Compensation for caloric dilution in humans given unrestricted access to food in a residential laboratory.

Six adult male research volunteers, in two groups of three subjects each, lived continuously in a residential laboratory for 14 days. All contact with the experimenters was through a networked computer system and subjects' behaviors, including food intake, were continuously recorded. During the first part of the day, subjects remained in their private rooms doing work activities. During the remainder of the day, they had the option to socialize with each other. A wide variety of food items were continuously available. Subjects were in complete control of their pattern of food intake and could consume any item, or number of items, at any time during the day. On days 6 through 11, reduced calorie versions of approximately one third of the food items were covertly substituted for the regular caloric content items. This manipulation decreased intake from the reduced-calorie group of foods by 500 kcal. The subjects immediately and completely compensated for the loss of calories by increasing the number of non-calorie-manipulated food items consumed. When regular calorie foods were again available during the last 3 days of the experiment, subjects failed to compensate for this increase in caloric intake. Thus, under conditions of unlimited access to food, human volunteers completely compensated for caloric dilution, but were less accurate in responding to increases in caloric intake.

Adult↗
PubMed1988

Human drug taking under controlled laboratory conditions.

The data presented point to the importance of studying drug effects under the conditions in which those drugs are taken outside of the laboratory. Interactions between the reinforcing and other direct effects of these drugs, as well as their interactions with ongoing environmental events, can only be evaluated under such conditions. Tolerance to cocaine's effects which can lead to a potential for increased toxicity, the regularity of both cocaine and marijuana self-administration under both stable and varying environmental conditions, and the regulation of caloric content of food all are important factors in understanding (and therefore being able to manipulate) substance use and abuse. These data also support the utility of a residential research facility for the investigation of substance use under conditions that approximate those in which people live outside of the laboratory. This unique laboratory, designed for continuous observation of human behavior over extended periods of time, provides a carefully controlled research environment with flexibility for establishing a range of subject behaviors and recording both individual and social behavior patterns. We can study regulation both within a day and over days, assessing the effects of experimental manipulations on the patterning of self-administration behavior. The design of such studies is a logical extension of those reported in the animal laboratory as well as those carried out in a more traditional human behavioral pharmacology laboratory.

Adult↗
PubMed1987

Marijuana and cocaine interactions in humans: cardiovascular consequences.

Seven adult male volunteers residing on a research ward received intravenous cocaine and smoked marijuana, alone and in combination, during daily experimental sessions. Following the determination of baseline cardiovascular indexes, a one gram marijuana cigarette (0-2.7% delta 9-THC w/w) was smoked. Cocaine hydrochloride (0-32 mg) was administered intravenously 13 minutes after the start of marijuana smoking. Cocaine alone produced dose-dependent increases in heart rate, while both low and high THC blood levels produced a similar increase in heart rate. Both doses of cocaine increased mean arterial pressure (MAP) similarly, while THC alone produced blood level dependent increases in MAP. Combinations of cocaine and marijuana increased heart rate above levels seen with either drug alone, with increases plateauing at nearly 50 bpm for all dose-blood level combinations. Increases in mean arterial pressure following combinations of cocaine and marijuana were equivalent to those produced by cocaine alone.

Adult↗
PubMed1987

Effects of smoked marijuana on social interaction in small groups.

Twelve adult male research volunteers, in four groups of three subjects each, resided continuously in a residential laboratory for up to 18 days. Subject's behaviors, including social interaction, were continuously recorded. During the first part of the day (1000-1600), subjects remained in their private rooms doing work activities, and during the remainder of the day (1600-2345), they had the option to socialize with the other subjects. Four cigarettes containing active marijuana (1.84%, delta 9-tetrahydrocannabinol (delta 9 (THC)), w/w) or placebo were smoked daily: one each prior to the work and social access period, and two during the social access period. When the results were averaged across all groups and individuals, active marijuana significantly increased total daily social interaction time. However, drug effects were a function of the baseline amount of social interaction. The results of these experiments also showed that the pattern of increases in social interaction following smoked active marijuana varied within different groups of individuals.

Adult↗
PubMed1986

Behavioral analysis of marijuana effects on food intake in humans.

Nine male research volunteers, in three groups of three subjects each, resided in a residential laboratory for up to 25 days. All contact with the experimenter was through a networked computer system and subjects' behaviors including food intake were continuously recorded. Subjects brought their own activities such as model-making, and these in combination with those provided by the laboratory resulted in rich behavior repertoires. During the first part of the day, subjects remained in their private rooms doing planned work activities, and during the remainder of the day, they were allowed to socialize. Cigarettes containing active marijuana (1.84% THC) or placebo were smoked prior to the private work period and during the social access period. A single active marijuana cigarette prior to the private work period had no effect on food intake. The administration of two or three active marijuana cigarettes during the social access period increased average daily caloric intake. The increased intake was due to an augmentation of calories consumed as between-meal snack items rather than an increase in meal size per se.

Adult↗
PubMed1986

Nicotine and caffeine effects on the task-elicited blood pressure response.

Nine subjects participated in four daily sessions during which a psychomotor task was performed prior to and following drug administration. Blood pressure was reliably increased by task performance, cigarette smoking, and caffeine administration. The effect of the combination of task performance, cigarette smoking and caffeine administration was additive, resulting in a markedly increased blood pressure during task performance for subjects smoking cigarettes and receiving caffeine.

Arousal↗
PubMed1985

Specific antagonism by RO 15-1788 of benzodiazepine-induced increases in food intake in rhesus monkeys.

Food intake of rhesus monkeys was limited to a single daily 2 hr session of banana flavored pellet availability, seven days a week. Following stabilization of intake, the effects of intragastric bromazepam, diazepam and pentobarbital, when given alone, were determined by delivering a dose twice weekly, 60 min before the session. Dose-dependent increases in food intake were observed with the following descending order of potencies: bromazepam, diazepam and pentobarbital. RO 15-1788 (0.5-1.0 mg/kg, IM), when given alone, five min before the session had no effect on food intake. When given in combination with bromazepam and diazepam, RO 15-1788 completely blocked the increases in food intake observed when the benzodiazepines were given alone. The specificity of this antagonism was shown by the failure of RO 15-1788 to alter the food intake increases induced by pentobarbital. These results confirm and extend previous reports of the specific antagonism of benzodiazepine behavioral effects by RO 15-1788 to an additional species and another behavioral effect of benzodiazepines.

Animals↗
PubMed1984

Response of monkeys to intragastric preloads: limitations on caloric compensation.

Food intake of rhesus monkeys was limited to a single daily 2 hr session of banana flavored pellet availability, seven days a week. Following stabilization of intake, the effects of liquid preload meals (0-80% of normal meal size) delivered through nasogastric tubes or chronic indwelling intragastric (IG) catheters were determined during test sessions by delivering preloads 15 min prior to the session. Monkeys compensated for preloads by decreasing intake by an amount nearly equal to the energy content of the preload. As the time between the delivery of an IG preload equivalent to 40% of a normal day's intake and the beginning of the session was increased, accuracy of compensation decreased. Monkeys also did not compensate for a chow meal given 2 hr before the session and compensation did not improve when this meal was given for ten consecutive days 2 hr before a session. In addition, an IG preload equivalent to 40% of a normal day's intake was given 20 hr before the session under two conditions: two hours after or immediately after the session on the day preceding testing. Only the preload given immediately after the session decreased food intake 20 hr later. However, a control volume of tap water delivered immediately after the session also decreased food intake 20 hr later. Finally, monkeys did not compensate for deprivation experienced one day by increasing their food intake the following day. In sum, these results indicate that under these conditions, the rhesus monkey does not regulate its food intake as accurately as previously reported.

Animals↗
PubMed1983

The effect of d-amphetamine and haloperidol alone and in combination on milk drinking in rats.

The effects of d-amphetamine (0.5-4.0 mg/kg IP) and haloperidol (0.015-1.0 mg/kg IP) alone and in combination on intake of a sweetened milk solution were determined in rats. Experimental sessions consisted of a 15-min access to the milk solution once a day, 7 days a week. d-Amphetamine was administered 15 min prior to the session and haloperidol was administered 60 min prior to the session. The interaction of these compounds was determined by repeated determination of the dose-response function for d-amphetamine in combination with different doses of haloperidol. When given alone, each drug produced a dose-dependent decrease in milk intake. In combination with haloperidol, the decrement caused by d-amphetamine was shifted to lower doses in a dose-dependent manner. Isobolographic analysis of the interaction indicates that the intermediate doses (0.03-0.06 mg/kg) of haloperidol were additive and the highest doses (0.12-0.25 mg/kg) of haloperidol were infraadditive with d-amphetamine. Dose-dependent neuropharmacological actions of these compounds may account for dose-dependent interactions.

Animals↗
PubMed1983

Effects of psychomotor stimulants, alone and in pairs, on milk drinking in the rat after intraperitoneal and intragastric administration.

The effects of cocaine, d-amphetamine and l-cathinone, alone and in pairs, on intake of a sweetened milk solution were determined in rats. Experimental sessions consisted of 15 min access to the milk solution daily, 7 days a week. After the determination of base-line intake, rats were assigned to one of two groups. All rats in one group received i.p. injections 15 min before the session and all rats in the other group received intragastric (i.g.) infusions 30 min before the session. A series of dose-response functions were then determined by giving a dose of a drug or a pair of drug doses once every 4 days. A wide range of doses of both drugs were tested in combination to fully characterize any interactions. When given alone, all three drugs produced dose-dependent decreases in milk intake. For each drug, higher doses were required to decrease milk intake when given i.g. than when given i.p. The decreasing order of potencies was d-amphetamine, l-cathinone and cocaine after i.p. administration and l-cathinone, d-amphetamine and cocaine after i.g. administration. In nearly every case, for both routes of administration, a drug produced dose-dependent shifts to the left of the dose-response function of the drug with which it was combined. Isobolographic analysis of the interactions indicates that d-amphetamine and l-cathinone were infra-additive (i.p.) or additive (i.g.), cocaine and d-amphetamine tended toward supra-additivity by both routes and l-cathinone and cocaine were additive or infra-additive by the i.p. route. The results of the i.g. cocaine and l-cathinone interactions could not be analyzed with isobolograms. The type of interaction was dependent on the particular drug pair, the particular dose combination tested and the route of administration.

Alkaloids↗
PubMed1982

The effects of cocaine in a gustatory avoidance paradigm: a procedural analysis.

When the presentation of a novel food to a rat is followed by the injection of certain compounds, the animal consumes less of that food on subsequent presentations. Conflicting results have been obtained when cocaine is used in this gustatory avoidance paradigm. In the present study, fluid intake of rats was limited to a single presentation, seven days a week. Following the determination of baseline water intake, sweetened fluid was given during the session following the determination of baseline water intake, sweetened fluid was given during the session followed by an injection of cocaine. In Experiment 1, 24.0 mg/kg cocaine-fluid pairings occurred on alternate days with two-bottle preference tests occurring between pairings. Animals treated with cocaine had lower preference ratios than saline controls although both groups consumed more novel fluid than tap water. In Experiment 2, preexposure to the fluid prior to pairing it with cocaine eliminated differences between cocaine and saline treated rats. In Experiment 3 no effect of cocaine on novel fluid consumption was seen in male or female rats when 24.0 mg/kg cocaine-fluid pairings were given for five consecutive days. In addition, 36 mg/kg cocaine when paired with novel fluid every other day failed to induce an avoidance response in Experiment 4. These results indicate that cocaine is a weak avoidance-producing agent in the gustatory avoidance paradigm, and suggests the need for a standardized procedure for studying drugs in this paradigm.

Animals↗