High-approach and low-approach positive affect influence physiological responses to threat and anger.

Positive affect has been related to faster cardiovascular recovery from stress. Although the family of positive affective states is diverse, no study examined whether high-approach positive affect (e.g., desire) has a different impact on peripheral physiological processes than more frequently studied low-approach positive affect (e.g., amusement). Building upon prior work on emotions and motivation, we expected that after controlling for arousal and valence, positive affect with higher motivational intensity would facilitate weaker recovery when compared to positive affect with lower motivational intensity. Across two experiments (N = 179 for Study 1, N = 220 for Study 2), we measured cardiovascular, respiratory, and electrodermal responses to positive stimuli that differed in approach intensity. We measured responses during recovery from stress and during reactivity to threat and anger. These studies partially replicated previous findings regarding the soothing function of positive affect (e.g., in respect to diastolic blood pressure recovery and reactivity). However, we found that high-approach and low-approach positive affect produced comparable effects. In summary, these findings suggest that positive valence rather than motivational intensity produces the main soothing effect on peripheral physiology.

Effects of emotions on heart rate asymmetry.

Heart rate asymmetry (HRA) is an index that accounts for an uneven contribution of decelerations and accelerations to the heart rate variability (HRV). Clinical studies indicated that HRA measures have additive clinical value over the more frequently used HRV indexes. Despite the abundance of studies on psychological influences on HRV, little is known whether psychological factors influence HRA. Based on previous research regarding HRA and stress, we expected that negative emotions compared to positive emotions would decrease the contribution of decelerations to HRV. Thirty female participants watched three clips that produced negative emotions, positive emotions, and neutral affect. Besides electrocardiogram, we measured several physiological and behavioral responses to ascertain the affective impact of the clips. Using the RR interval time series, we calculated HRV and HRA indexes. We found that HRA differentiated between positive emotions and negative emotions reactivity. Positive emotions produced a higher number of decelerations in short-term variability to the total short-term variability (C1d ) compared to negative emotions. Moreover, C1d correlated with subjective ratings of affect. In sum, the results of this study indicated that HRA is sensitive to psychological influences. HRA indexes are likely to contribute to a more nuanced physiological differentiation between emotions.

[Nicotine and caffeine: influence on dopaminergic transmission].

Dopamine plays an important role in the neuronal regulation of motivation / reward, voluntary movements, cognitive processes and the process of addiction. Disorders of the production and release of dopamine can be the base of the pathomechanism of many diseases. Both nicotine and caffeine are psychomotor stimulants. Caffeine, through inhibition of adenosine, increases the activity of the dopaminergic system, and it shows the reinforcing and the psychomotor effect. Nicotine gets its reinforcing and psychostimulant effects from blocking dopamine uptake and increasing synaptic dopamine release. Nicotine and caffeine affect the release of the dopamine. It is believed that the interaction of these substances may be a synergistic effect on pain perception, voluntary movement functions or behavioral traits.

Influence of the interactions between tea (Camellia sinensis) extracts and ascorbic acid on their antioxidant activity: analysis with interaction indexes and isobolograms.

Products containing natural additives, including antioxidants, are usually perceived by consumers as safer than those with synthetic ones. Natural antioxidants, besides having a preservative activity, may exert beneficial health effects. Interactions between antioxidants may significantly change their antioxidant activity, thus in designing functional foods or food/cosmetic ingredients knowledge about the type of interactions could be useful. In the present study, the interactions between ascorbic acid (AA; vitamin C) and different black and green tea extracts and the influence on their antioxidant activities were investigated. The antioxidant activities of tea extracts and their mixtures with AA prepared in several different weight ratios were measured using the trolox equivalent antioxidant capacity (TEAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric-reducing antioxidant power (FRAP) methods. The type of interaction was determined by interaction indexes and isobolograms. It was found that the weight ratio of extracts to AA significantly influenced the antioxidant activity of a mixture and the type of interaction between these components. The weight ratio of tea extract to AA can cause the change of interaction, e.g. from antagonism to additivism or from additivism to synergism. The observed differences in the type of interactions were probably also a result of different extracts' polyphenol composition and content. The type of interaction may also be affected by the medium in which extracts and AA interact, especially its pH and the solvent used. To obtain the best antioxidant effect, all these factors should be taken into account during the design of a tea extract-AA mixture.

[Cigarette and coffee--pharmacokinetics interaction between nicotine and caffeine]. / Papieros i kawa--interakcje farmakokinetyczne nikotyny i kofeiny.

Coffee drinking and tobacco smoking stand nicotine and caffeine the number one licit psychoactive substances. Many people inseparably combine a cup of coffee with cigarette. The two most important compounds in these products, nicotine and caffeine can influence on there concentration and pharmacodynamics activity in the body. The changes of the level of these compounds can be caused by changes of the pharmacokinetics on the way of enzyme induction by other chemical individuals content in the coffee and tobacco smoke.