Actions of caffeine in the brain with special reference to factors that contribute to its widespread use.
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Animals↗
Biomedical subjects
K Bättig
Publications and source records attributed to K Bättig.
Effects of a 2-day abstinence from smoking on dietary, cognitive, subjective, and physiologic parameters among younger and older female smokers.
In a field study, dietary intakes, subjective ratings of well-being, cognitive performance, blood pressure, and heart rate were assessed during 6 days of ad libitum smoking and 2 days without smoking by using an electronic diary. The subjects were 59 younger and older female smokers, aged 25-35 and 55-65 years, respectively. Smoking abstinence significantly lowered heart rate, blood pressure, and saliva cotinine levels, indicating a good compliance by the subjects. Smoking abstinence was also followed by subjectively reported decreased levels of relaxation and activity and by higher levels of sleepiness, negative strain, and craving for smoking. Mental performance as assessed with the Stroop task was not affected by smoking abstinence. Whereas the percentage distribution of the macronutrients did not change with smoking abstinence, the intake of total energy increased significantly by 182 kcal/day. Main effects of age were found on some of the dietary parameters and Stroop performance variables only. A post hoc analysis revealed a significant influence of the employment status factor on the excess caloric intake and the increased frequency of sweet consumption when under abstinence. These increases were significantly greater in nonemployed (housewives, jobless) than in working women. Further correlational analysis revealed strong relations between caloric intake and simultaneous craving for smoking and food during abstinence but not during nonabstinence days, whereas no relation between caloric intakes and saliva cotinine or respiratory carbon monoxide were obtained. These findings suggest that the availability of food products and subjective withdrawal symptoms are probably more important moderators of increased dietary intake following smoking cessation than any pharmacologic systemic effects of nicotine.
Adult↗
Labyrinth exploration, emotional reactivity, and conditioned fear in young Roman/Verh inbred rats.
An inbreeding program has been carried out with the Swiss sublines of Roman high- and low-avoidance rats since 1993. The present study reports the first experiments conducted with young animals of those inbred strains (RHA-I/Verh and RLA-I/Verh, respectively) from the sixth and seventh inbreeding generations. The results confirmed expected behavioral profiles. Compared to the RHA-I/Verh strain, RLA-I/Verh rats showed decreased entries into the illuminated central arena of an hexagonal tunnel maze, as well as decreased spontaneous locomotor activity and increased defecations, in two independent experiments. Young RLA-I/Verh females explored less than did their RHA-I/Verh counterparts during session 1 of a conditioned-fear experiment preceding shock administration, and in session 2 (conducted 24 h after the application of three footshocks), they showed greater conditioned behavioral inhibition (i.e., reduced amount of rearing), as well as higher defecation scores, than did RHA-I/Verh females.
Analysis of Variance↗
Comparison of an electronic food diary with a nonquantitative food frequency questionnaire in male and female smokers and nonsmokers.
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Computers↗
Comparison of the effects of nicotine on a fixed rate and a subject-paced version of the rapid information processing task.
In a modified "subject-paced" rather than fixed rate version of a rapid information processing (RIP) task, the presentation rate of the stimuli is continuously adapted to the individual performance level. Thus, this modified task version probably assesses a continuous "speed function" rather than mere "vigilance". In order to compare the two task versions more directly, we carried out a study which assessed the effects of a regular nicotine cigarette and the nearly nicotine-free cigarette NEXT on both task versions under the same experimental conditions. The dominant alpha frequency pointed to a greater arousal evoked by the subject-paced RIP version compared with the fixed rate version. With the fixed rate version, smoking nicotine cigarettes reduced reaction times, whereas with the subject-paced version, processing rate was improved. Additionally, smoking NEXT decreased craving less than smoking the regular cigarettes. It was concluded that the two task versions are sensitive to different cognitive functions. Whereas the subject-paced version was more sensitive to effects on the speed of processing, the fixed rate version was more sensitive to effects on reaction time.
Adult↗
Switching to ultralow nicotine cigarettes: effects of different tar yields and blocking of olfactory cues.
Twelve female smokers smoked two of each of three types of cigarettes in three sessions. One cigarette was smoked with and the other one without nose blocking. Total puff volumes increased for ultralow tar/nicotine (tn) cigarettes as compared with habitual regular tar/nicotine (TN) cigarettes and regular tar/ultralow nicotine (Tn) cigarettes, as the result of an increase in the number of puffs. TN and tn, but not Tn cigarettes changed heart rate and beta-power in the electroencephalogram; all three reduced craving, although they differed considerably in subjective acceptance. Blocking of olfactory cues influenced respiration and reduced the average puff volumes, taste, and enjoyment, but it did not differentially affect any parameters among the TN, tn, and Tn cigarettes, which suggests that olfaction plays a minor role in regulating puffing behavior. It was concluded that as compared with regular TN cigarettes, only the tn, but not the Tn cigarettes were oversmoked by about 35%, and that Tn cigarettes might be useful for assessing nonnicotinic factors in cigarette smoking.
Adult↗
Evaluating activity and emotional reactivity in a hexagonal tunnel maze: correlational and factorial analysis from a study with the Roman/Verh rat lines.
Two hundred forty 30-day-old Roman high- and low-avoidance (RHA/Verh and RLA/Verh) rats (divided equally by line and gender) which had received several peri- and/or postnatal treatments, forming two factorial [line x sex x treatment(s)] experimental designs, were tested in a hexagonal tunnel maze including a brightly illuminated central arena. The present study reports the results of correlational and factorial (principal-components) analyses performed on the data from those two experimental constituencies. The purpose of the study was to evaluate the validity of the hexagonal tunnel maze for testing emotionality, and therefore, the following measures were included in the analysis: entries into the central illuminated arena, total activity during testing, defecation during testing, and defecation during handling and weighing after testing. An overall pattern of negative correlations (or opposite loadings in the principal-components analyses) between defecation (especially during maze testing) and entries into the illuminated center and activity was found, thus giving support to the validity of entries into the illuminated center as being indicative of emotional reactivity.
Animals↗
Acute dose-effect relationships of caffeine and mental performance, EEG, cardiovascular and subjective parameters.
The present study investigated the dose-effect relationship of caffeine on mental performance using a caffeine-sensitive rapid information processing task (RIP) in a pre/post cross-over design. Twenty female nonsmoking regular coffee drinkers received 0, 1.5, 3 and 6 mg/kg caffeine in a balanced order and the measurements were extended to cardiovascular, EEG and mood parameters. Surprisingly, the dose-effect curves for the different parameters were rather heterogeneous. Whereas increasing effects with increasing caffeine doses were observed for alpha- and beta-EEG frequencies, anxiety, wakefulness, and some coffee ratings, negative dose-effect relationships were obtained for RIP processing rate and blood pressure. No apparent dose-effect relationships were seen for reaction time and motor activity. Thus, it was concluded that the dose-response relationships are rather shallow and heterogeneous and that the different parameters have different ranges in which they are sensitive to caffeine. The caffeine doses which might have beneficial behavioral effects are at the lower end of the tested dose range and comparable to those found in caffeine-containing beverages.
Adult↗
Ultralight cigarettes: activity, cardiovascular, dietary, and subjective parameters.
In a field study, 24-h heart rate, physical activity, and cigarette consumption were continuously recorded, whereas resting heart rate, blood pressure, dietary intake, and subjective parameters were assessed six times per day. Smoking habitual and ultralight cigarettes for two days each was compared in a sample of 48 smokers, consisting of 24 office and 24 nonoffice workers of both sexes. Nonoffice workers smoked more and revealed higher respiratory CO and Fagerstrom index values, whereas other group differences were unrelated to smoking or its effects. Switching to ultralight cigarettes with four- to eightfold lower nicotine yields than the habitual cigarettes significantly decreased respiratory CO by 5 ppm, saliva cotinine by 30%, resting heart rate by 2.5 bpm, systolic blood pressure by 3.5 mmHg, and diastolic blood pressure by 3.0 mmHg, but increased fat intake by about 400 kJ, whereas activity and subjective well-being were not affected. Thus, the reduction in saliva cotinine was considerably smaller than the reduction in nicotine yield, and the effects on physiological parameters therefore were rather modest.
Adult↗
Cardiovascular, behavioral, and subjective effects of caffeine under field conditions.
The effects of continuous and intermittent caffeine abstinence and their time course were investigated under field conditions. After 3 days with habitual coffee, subjects were switched for 9 days to regular instant coffee (n = 40), decaffeinated coffee (n = 40), or an intermittent regime (2 days decaff, 1 day caff, repeated, n = 40). Subjects were blind to the caffeine treatment. Motor activity was assessed continuously; subjective variables, blood pressure (BP), and heart rate (HR) were assessed by the subjects six times per day (electronic diary). Compliance was confirmed by the different caffeine concentrations in daily saliva samples. Continued caffeine consumption showed no effects. Caffeine abstinence resulted in increased HR, decreased motor activity, subjective wakefulness, and well-being, and in increased headaches and use of analgetics. The subjective effects and headaches were transient, i.e., they disappeared after a few days of abstinence and weakened over successive, separated abstinence periods. BP was not affected by the caffeine treatment. The intermittent onset of caffeine consumption resulted in increased wakefulness, whereas the other variables normalized to baseline level.
Adult↗
Circadian and ultradian rhythms in heart rate and motor activity of smokers, abstinent smokers, and nonsmokers.
In a field study, heart rate and motor activity were assessed continuously in 12 male smokers during 2 smoking and 2 abstinence days and in 12 male nonsmokers during 4 days. A circadian analysis revealed earlier activity acrophases in smokers than nonsmokers and earlier heart rate acrophases in abstinent than smoking smokers. Furthermore, heart rate acrophases of smoking smokers significantly anticipated activity acrophases, whereas in abstinent smokers and nonsmokers the two parameters oscillated in phase. With the use, in smoking smokers, of the individual average smoking interval as a hypothetical ultradian period length, significant periodicities were found for heart rates in 16 and for activity in 15 of 24 observation days. These rhythms were nicotine independent and based on heart rate and activity increases prior to lighting up the cigarettes. Individual frequency spectra for the 16 h after getting up and the 7 h after going to bed did not reveal single dominant frequencies but rather complex frequency distributions. Power spectra of the daytime data revealed no group differences for activity and no heart rate differences between smoking smokers and nonsmokers. In abstinent smokers, however, a significant reduction of heart rate frequencies slower than 1 cycle/135 min and a significant increase of heart rate frequencies faster than 1 cycle/20 min were observed as compared with all other groups. This effect persisted over the 2 abstinence days, suggesting an activity-independent change in the frequency distribution of heart rates after quitting smoking.
Activity Cycles↗
Psychophysiological interactions between smoking and stress coping?
Earlier studies with different types of stressors suggested that cigarette smoking might selectively dampen physiological stress reactions in passive rather than in active coping situations. This hypothesis was tested in the present study using the same task for both types of coping, but with two different instructions. Twenty-four female regular smokers were assigned either to a group requiring active coping or to a group requiring passive coping with ongoing electric shocks, and tested in two sessions where they performed a pre- and a postsmoking/non-smoking trial of the rapid information processing task (RIP). Smoking increased RIP task performance, cardiovascular and electrocortical arousal, and reduced anxiety throughout the session. Active coping, as compared to passive coping, produced greater increases in heart rate and blood pressure, a greater pre- to post-treatment decrease in reaction time and higher pain ratings of the electrical shocks. However, interactions between the effects of smoking and the type of coping were few and did not suggest a plausible concept. Thus, it was concluded that, although the typical effects of smoking as well as the differentiation between active and passive coping seen earlier with the same paradigm were confirmed, cigarette smoking did not affect the effects of the two coping conditions in a differential way.
Adaptation, Psychological↗
Nicotine or tar titration in cigarette smoking behavior?
A significant problem in assessing the relative relevance of nicotine and tar yield for compensatory smoking after switching from high to low yield cigarettes is that nicotine and tar yield are highly intercorrelated across conventional cigarettes and that the tar/nicotine ratios vary only within a modest range. A better differentiation between the impacts of nicotine and tar yield was expected by comparing in a laboratory experiment a new low nicotine/medium tar cigarette ("Next") with conventional low nicotine/low tar (ultra-light) cigarettes and with medium nicotine/medium tar cigarettes with respect to nicotine absorption and physiological effects. Twelve females, habitually smoking medium type cigarettes (> or = 0.7 mg nicotine) participated in the study. Neither the number of cigarettes smoked under field conditions nor the puffing behavior during the laboratory experiment differed between the three types of cigarettes. In the laboratory, Next produced only very small increases in plasma nicotine and changes in cardiovascular or EEG measures, whereas the effects of the medium cigarettes were in the expected range and those of the ultra-light cigarettes about halfway in between. The nicotine absorption/nicotine yield and the CO absorption/CO yield ratios were similar for Next and the habitual cigarettes, but about twofold higher for the ultra-light cigarettes. This suggests that gustatory and olfactory sensations, which are supposed to be more dependent on tar than on nicotine yield, may play a greater role for the regulation of smoking behavior than hitherto believed.
Adult↗
Cigarette smoking related variation of heart rate and physical activity with ad libitum smoking under field conditions.
A recently developed device was used in a field study to continuously assess physical activity, heart rate, and cigarette lighting during 2 workdays and 2 days off in 12 female smokers and 12 female non-smokers. Heart rates did not differ between smokers and non-smokers or between workdays and days off; however, the nonsmokers showed significantly higher physical activity during the workdays. An averaging procedure used to obtain plots for smoking related changes of activity (SRA), pulse (SRP), and the pulse-activity ratio (SRpai) revealed four observations. a) "Lighting" responses consisting of parallel increases of SRA and SRP start a few minutes before lighting, reach a maximum with lighting, and drop immediately after lighting. b) The subsequent "smoking" responses last about 6 min and are characterized by a sustained postlighting SRA depression but immediate recovery of SRP, resulting in an increased SRpai level. c) Ten minutes prelighting and 10 min postlighting SRA and SRP are highly similar. d) The pattern of this response was similar for workdays and days off.
Adult↗
Ischemic ECG changes are found more often in asymptomatic men with a coronary prone behaviour pattern.
Type A behaviour has been related to coronary heart disease (CHD) as an independent risk factor. Therefore, ischemic electrocardiographic (ECG) changes may be more prominent in Type A than in Type B individuals. ECG abnormalities were assessed by the Cardiac Infarction Injury Score (CIIS), which has predictive power for sudden death. In 100 healthy men aged 30-45 yr, the CIIS was related to cardiovascular risk factors such as age, blood pressure, smoking, family history of CHD and behaviour pattern groups defined by the Structured Interview (46 Type A, 20 Type X and 34 Type B subjects). The distribution of the CIIS was different among the behaviour pattern groups (p < 0.05) and was shifted towards higher ischemic scores in Type A subjects. These findings suggest that clinically asymptomatic persons with Type A behaviour have a greater probability of suffering ischemic heart disease and possible sudden death.
Adult↗
Postnatal handling, perinatal flumazenil, and adult behavior of the Roman rat lines.
The effect of infantile handling stimulation and/or perinatal flumazenil (Ro 15-1788; a benzodiazepine receptor antagonist; 3.7 mg/kg/day) administration on exploratory and emotional-related behavior was investigated using adult females from the Roman high- and low-avoidance (RHA/Verh and RLA/Verh) lines. When rats (6 months old) were exposed to a hexagonal tunnel maze including an illuminated central arena, it was found that RHA/Verh rats were more active, explored more maze area, showed more outward preference, and more frequently entered the illuminated center than RLA/Verh rats. In addition, postnatal stimulation decreased emotional-related behavior in both lines of rats, as expressed by increased entry into, and time spent in, the central arena. Perinatal flumazenil treatment decreased entry into the maze central arena in both rat lines but this effect was counteracted by postnatal (handling) stimulation. Thus, the present study extends to adult RHA/Verh and RLA/Verh rats the positive long-lasting effects of postnatal handling and shows postnatal handling x flumazenil interactions in some behavioral parameters related to the pattern of exploration and exploratory efficiency.
Animals↗
Coffee consumption, blood pressure tonus and reactivity to physical challenge in 338 women.
The relationships of coffee consumption habits and cardiovascular tonus at rest and in response to an orthostatic and an ergometric challenge were determined in 338 nonsmoking women. Habitual coffee consumption was unrelated to blood pressure. Coffee consumption on the test day was associated with slightly higher systolic blood pressure at rest and with smaller increases due to ergometer cycling. The latter was confirmed by a similar relation with saliva caffeine concentrations measured in a subsample (n = 200). These findings are discussed in terms of a transient stabilising effect of caffeine on blood pressure.
Adult↗
Antagonistic effects of caffeine and alcohol on mental performance parameters.
Scientific experiments done so far allow no clear conclusions about the popular belief that freshly brewed coffee can offset the debilitating effects of alcoholic intoxication. This question was addressed using a computer-controlled and subject-paced rapid information processing task (RIP) which was shown earlier to be sensitive to psychoactive substances. Nine male students were tested in a Latin square design before and after the intake of 3.3 mg/kg caffeine (or placebo) followed by 0.7 g/kg alcohol (or placebo). Whereas the mean RIP-task processing rate and the mean reaction time were impaired by alcohol and improved by caffeine, no changes were observed after the combination of alcohol and caffeine. Thus, it was concluded that under the tested conditions, caffeine was able to offset the debilitating effects of alcohol.
Adult↗