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Biomedical subjects

M E Jarvik

Publications and source records attributed to M E Jarvik.

At least 91 records · Page 5Linked to original sources
PubMed1976

Reactions to cigarettes as a function of nicotine and "tar".

Experiments carried out to examine the effects of nicotine and "tar" on the extent of and subjective reactions to cigarette smoking. It was confirmed that smokers rate commercial, low-nicotine cigarettes as less "strong" and less "satisfying" than their usual brands. Since such cigarettes deliver reduced amounts of tar as well as of nicotine, an experiment to distinguish between the two was carried out with special cigarettes. Ratings of "strength" were directly related to nicotine but were not affected by tar. The numbers of cigarettes smoked fell slightly as their estimated delivery of nicotine increased, but tar had no effect on this index. The urinary excretion of nicotine was correlated with the rated yields of nicotine for the different cigarettes, but there was also evidence that subjects tended to adjust their manner of smoking so as to titrate their doses of nicotine. The results are interpreted as indicating a role for nicotine, but not for tar, in the maintenance of cigarette smoking behavior, and as support for the view that less harmful cigarettes should have a high yield of nicotine relative to tar.

Adult↗
PubMed1976

Naltrexone: physiological and psychological effects of single doses.

An ascending series of single doses of the narcotic antagonist naltrexone, ranging from 20 to 160 mg, was administered to 8 abstinent former addicts in order to assess agonistic activity and any toxic side effects. There was little alteration of normal body function. Significant, but small, changes in sublingual temperature (0.4 degrees F decrease), and diastolic blood pressure (1.7 mm Hg increase) were induced. Among the battery of tests assessing behavioral or mood-feeling variables, only 2 showed significant between-condition effects: facilitated performance on the Cross-out Test (attention and perception), and a dose-related decrease in Morphine-Benzedrine Group (MBG) scores of the Addiction Research Center Inventory (ARCI) (mild euphoria). On the whole, subjects had few subjective reactions or unpleasant side effects. Naltrexone appears to be a safe, nontoxic medication in the dosage range examined.

Blood Pressure↗
PubMed1976

Titration of nicotine intake with full-length and half-length cigarettes.

Titration, the self-regulation of nicotine intake, was studied in 12 smokers by gas chromatograph assays of urinary nicotine levels. Results demonstrated that excretion of urinary nicotine in the proximal condition (half cigarette close to the filter) did not differ significantly from the whole cigarette condition; however, less nicotine was excreted in the distal condition (half cigarette farther from the filter) because of a rod filtration effect. Subjects extracted proportionately more nicotine from the half than from the whole cigarettes; titration was approximately the same in both half-cigarette conditions. On scales of strength and satisfaction, full-length cigarettes were given the highest rating, followed by proximal and then distal cigarettes.

Adult↗
PubMed1976

Cocaine self-administration in monkeys by chewing and smoking.

Two rhesus monkeys self-administered cocaine hydrochloride in a gum base vehicle on a fixed ratio 10 schedule with performance characterized by frequent pauses and increased intertrial interval responding. Three other monkeys self-administered cocaine base in lettuce cigarette vehicles in smoking performance marked by shortened puff durations. Urinary benzoyl ecgnoine levels correlated with amount of cocaine chewed or smoked. Monkeys did not prefer cocaine gum in choice tests with plain or procaine gum, but did significantly prefer cocaine cigarettes to plain cigarettes. These preliminary results emphasize the importance of route of administration in determining reinforcement efficacy of human coca use and suggest animal models for their further experimental analysis.

Animals↗
PubMed1976

Effects of ACTH peptide fragments on memory formation.

The effects of peptides derived from ACTH on the formation of long-term memory have been investigated in male mice. Post-training administration of ACTH 4-10-L-Phe-7 (ACTH-L) improved retention for both passive and active avoidance tasks. Administration of ACTH 4-10-D-Phe-7 (ACTH-D) impaired retention for both tasks. The optimum dose for ACTH-L was about 0.3 mg/kg; the optimum dose for ACTH-D was in the range of 1.0-3.0 mg/kg. Using the passive avoidance task, it was shown that either drug had to be administered within 60 min of training to be highly effective. Amnesia produced by anisomycin (Ani), an inhibitor of protein synthesis, was lessened by ACTH-L and increased by ACTH-D, ACTH-D opposed the memory facilitating effects of ACTH-L. Using intact mice, ACTH-L or ACTH-D did not significantly change the incorporation of valine into protein, nor did these peptides influence the inhibition of protein synthesis caused by anisomycin. The results show that ACTH may play a major role in memory processing, perhaps by facilitating essential protein synthesis at sites specific for the memory being established.

Adrenocorticotropic Hormone↗
PubMed1976

Amnesic actions of diazepam and scopolamine in man.

In man, diazepam alone and in combination with scopolamine interferes with the memory of visual and painful stimuli. With a 15-minute interval between injection of the drug and the showing of emotionally neutral pictures, scopolamine (0.5 mg/70 kg) produces 14 per cent forgetting when evaluated 24 hours later. Under these conditions diazepam (10 mg/70 kg) produces 41 per cent forgetting, while the combination causes 64 per cent. Under conditions designed to insure selection of subjects in whom registration was clearly quite intact at the time of the initial exposure to the pictures, memory was still found to be impaired when tested 24 hours later. Graded doses of diazepam to as much as mg/70 kg in combination with 0.5 mg/70 kg scopolamine produced a virtually linear dose-response curve for amnesia. These results are compatible with the interpretation that the diazepam-scopolamine mixture interferes with memory by blocking consolidation of the memory trace.

Adolescent↗
PubMed1976

Observational determination of dose-response curves in hallucinogen-treated monkeys.

An objective behavioral profile that was previously shown to distinguish the effects of hallucinogens from those of other classes of drugs was used here to further study hallucinogenic behaviors. Saline, d-amphetamine sulfate and five doses of dimethyltryptamine (DMT) were administered to solitary adolescent rhesus monkeys in a totally dark environment and their behavior was observed via infrared monitors, videotaped, and scored in a number of categories. Scores in the following categories systematically increased with ascending doses of DMT; exploration, locomotion, stereotypy, spasm, tracking and duration of inappropriate behavior. In addition, some behaviors sensitive to hallucinogens occurred with greater frequency in the dark than in a previous study conducted in the light. Behaviors such as tracking and fear grimaces, usually associated with specific stimuli, emerged in the absence of such stimuli in the dark. These results suggested hallucinogen-induced changes in perceptual-motor systems, if not hallucinations per se.

Animals↗
PubMed1976

The effects of hallucinogens on blind monkeys.

Two blind monkeys were studied with an observational profile that was previously shown to distinguish the effects of hallucinogens from those of other classes of drugs. Lysergic acid diethylamide and dimethyltryptamine could be distinguished from saline, chlorpromazine, d-amphetamine sulfate, and bromo-lysergic acid diethylamide by the increased frequency of spasms, stereotypy, bump, and tracking. The hallucinogens also produced dramatic increases in exploration and related behaviors normally seen only in response to real visual or auditory stimuli. These behaviors are discussed in terms of their similarity to behaviors observed with sighted monkeys in light and dark environments.

Animals↗
PubMed1975

Weight loss and shock-elicited aggression as indices of morphine abstinence in rats.

Weight loss and shock-elicited aggression have been compared as quantitative indices of morphine abstinence in rats. A range of doses of morphine was administered to rats by i.p. injection twice daily for 12-15 days. After injections were stopped, morphine-abstinent rats lost weight precipitously, and showed an increased frequency of fighting in response to aversive stimulation (foot-shock). Recovery of weight appeared complete after 15-20 days but a significant increase in aggression was found at 18 days post-withdrawal; this virtually disappeared after 52 days. Both the amount of weight lost and the frequency of fighting increased as a function of the previous maintenance dose of morphine; the effective dose range appeared similar for these two indices. Weight loss was much less variable than fighting, had the advantage of rapid, objective measurement, and appeared to be the more reliable index of abstinence.

Aggression↗
PubMed1975

Physiological and psychological effects of methadone in man.

Methadone hydrochloride-maintenance outpatients were compared to abstinent exaddicts on physiological and psychological measures, and to normal subjects on physiological measures. The battery of psychological tests measure cognitive abilities and mental state. Methadone depressed respiration rate below other groups; abstinent subjects had higher heart rates than methadone or control subjects. No other physiological differences appeared. Electroencephalographic spectral analysis disclosed that the location of the alpha peak was at the lowest frequency in the methadone group, next lowest being the abstinent group. Discriminant functions based on a weighted combination of variables (frequencies) successfully distinguished the EEGs of the three groups. Both discriminant analysis and multiple regression analysis indicated that EEG changes were dose-dependent. Methadone subjects performed significantly poorer on several tests of learning and immediate recall compared to absitinent subjects.

Administration, Oral↗
PubMed1975

Nicotine regulation and cigarette smoking.

A study was conducted to determine whether there is nicotine regulation in cigarette smoking. Tar levels, which often covary with nicotine manipulations, were controlled for by the use of nicotine in chewing gums. Nicotine in cigarettes was also used for preloading. High nicotine cigarette preloads were followed by longer latencies to the next cigarette than were the low nicotine cigarette preloads. High nicotine gum preloads were followed by less puffing on the subsequent cigarettes than were the low nicotine gum preloads.

Chewing Gum↗
PubMed1975

Age differences in learning, immediate and one week delayed recall.

In an initial study, differences in learning and immediate recall were observed for groups of young and aged subjects on several measures. Retest date showed some differential loss for aged subjects after 1 week. Conclusions regarding long-term retention per se were not possible due to the nature of the design. In a second study, additional aged and young groups of subjects were run under delayed recall conditions. The data from these two groups were combined with data from the first study, with care taken to match subjects on a number of variables (health, education, intelligence). The results showed age-related differences for measures of learning and immediate recall but not for delayed 1 week retention.

Adult↗
PubMed1975

Naloxone-induced jumping in morphine dependent mice: stimulus control and motivation.

When naloxone-precipitated abstinence occurs in morphine-dependent mice, they exhibit stereotyped jumping. The number of jumps has been used as an abstinence measure and the motivation for them described as 'escape'. Studies were designed to assess stimulus control and motivation here. Groups of ten dependent and ten saline mice were singly tested in both light and dark conditions in each of five covered cylinders (2-23 in high). Jumps were recorded automatically for 10 min after 10 mg/kg naloxone. At 2 in, which permitted tactile contact with the cover, no jumps occurred in the light or the dark; at 5-11 in, a high incidence of jumping occurred in both the light and the dark; at 23 in, too high for the animal to reach, relatively few jumps occurred in the light but many occurred in the dark. In another study, similar groups were singly tested in the light after naloxone on each of five circular platforms (18 in high, 3-48 in diameter). As the diameter increased, the number of mice jumping to the floor showed a linear decrease concomitant with an increase in latency. This suggests that jumping is controlled by visual and tactile cues; mice do not jump when escape is prevented by a cover which can be touched or a height which cannot be reached; but do jump when such cues are eliminated by intermediate heights or darkness. Latency varies with size of immediate explorable environment.

Animals↗