Högskolan i Skövde

The aim of this exploratory study was to investigate interactive behaviors performed between residents at nursing homes and a therapy dog and her handler and explore if they influenced residents’ physiological variables such as fingertip temperature, heart rate, and systolic and diastolic blood pressure. The therapy dog–handler team visited 12 older people at three nursing homes for 60 min twice a week during a four-week period. The visits were videotaped, and the duration of interactive behaviors was recorded. The physiological variables were measured before (0 min) and after (60 min) the interaction between the residents and the dog–handler team, and the delta value was calculated. The interactive behaviors during the first two and the last two weeks were as follows: the resident looking at the dog (799 and 697 s/h), the resident in physical contact with the dog (183 and 109 s/h, p < 0.001, Wilcoxon signed-rank test), the resident playing with the dog (123 and 126 s/h), the resident talking with others (559 and 511 s/h), and the dog handler having physical contact with the resident (822 and 764 s/h). The mean values for fingertip temperature, heart rate, and systolic and diastolic blood pressure did not differ significantly between the first and two last weeks (paired t-test). However, the delta values varied largely between the different residents. The more physical contact the residents had with the dog handler, the more the fingertip temperature increased (p < 0.05, mixed linear model). The duration of physical contact between the residents and the dog tended to be associated with an increased fingertip temperature (p < 0.1). Furthermore, the more the residents were in verbal contact with the dog handler, the more their heart rate decreased (p < 0.05). These results demonstrate some associations between specific interactive behaviors and physiological changes in residents in connection with visits by a dog–handler team.

The stimulant ± 3,4-methylenedioxymethamphetamine (MDMA) has been shown to enhance the perceived pleasantness of touch. However, the underlying neural processes contributing to touch-related effects of MDMA are not well understood. Using a double-blind, randomized, within-subject design, this study used fMRI to examine hemodynamic changes following MDMA (1.5 mg/kg) vs. lactose placebo administration during gentle touch stimulation in a healthy sample (N = 18). Participants were stroked on the forearm at a slower, more pleasant (3 cm/s), and a faster (30 cm/s), less pleasant speed. For the MDMA session, participants’ affective ratings of touch stimulation were higher than their placebo ratings. Increase in plasma oxytocin (OT) levels was also greater during the MDMA session. On the neural level, primary sensorimotor areas showed greater hemodynamic changes during the MDMA than during the placebo session for both touch speeds, indicating a relatively early influence within somatosensory pathways. Changes in OT levels showed an interaction with drug in an occipitotemporal region, area MT+, associated with motion perception. However, posterior insula did not show preferential activation for the slower stroking speed. These initial findings provide a basis for extending our knowledge of the neural processes underlying the effect of MDMA on affective touch.

Both oxytocin (OT) and touch are key mediators of social attachment. In rodents, tactile stimulation elicits endogenous release of OT, potentially facilitating attachment and other forms of prosocial behavior, yet the relationship between endogenous OT and neural modulation remains unexplored in humans. Using serial sampling of plasma hormone levels during functional neuroimaging across two successive social interactions, we show that contextual circumstances of social touch facilitate or inhibit not only current hormonal and brain responses, but also calibrate later responses. Namely, touch from a male to his female romantic partner enhanced subsequent OT release for touch from an unfamiliar stranger, yet OT responses to partner touch were dampened following stranger touch. Hypothalamus and dorsal raphe activation reflected plasma OT changes during the initial interaction. In thesubsequent social interaction, time- and context-dependent OT changes modulated precuneus and parietal-temporal cortex pathways, including a region of medial prefrontal cortex that also covaried with plasma cortisol. These findings demonstrate that hormonal neuromodulation during successive human social interactions is adaptive to social context, and point to mechanisms that flexibly calibrate receptivity in social encounters.

The aim of this call was to collect papers describing how oxytocin may be released by different kinds of sensory stimulation to induce wellbeing and restorative processes and to inhibit pain, stress and inflammation. A large number of interesting articles of very high quality were received and 19 papers were accepted for publication. All the included articles have contributed to expand the knowledge about oxytocin in a very substantial way both regarding its effect spectrum and regarding its association with sensory, somatosensory stimulation, in particular. In fact, the obtained data contribute to prove the hypothesis that the oxytocinergic system is a widespread integrative system, which is linked to social interaction, wellbeing, reduction of stress and pain as well as to reproductive, growth promoting and restorative effects. The activity of this archaic oxytocin system is under control of hormones and sensory nerves, which convey information regarding the state of the internal and the external environment. The oxytocin linked effects may be induced in the short-term as well as in the long-term perspective. All of the articles which were accepted and included in this issue, in their own unique way, contribute to describe oxytocin beyond its classical role in birth and milk ejection in accordance with the concept described above. We describe and discuss the data after having categorized the results presented in the articles according to certain subjects. 

Background

Two important aspects for the development of anxiety disorders are genetic predisposition and alterations in the hypothalamic-pituitary-adrenal (HPA) axis. In order to identify genetic risk-factors for anxiety, the aim of this exploratory study was to investigate possible relationships between genetic polymorphisms in genes important for the regulation and activity of the HPA axis and self-assessed anxiety in healthy individuals.

Methods

DNA from 72 healthy participants, 37 women and 35 men, were included in the analyses. Their DNA was extracted and analysed for the following Single Nucleotide Polymorphisms (SNP)s: rs41423247 in the NR3C1 gene, rs1360780 in the FKBP5 gene, rs53576 in the OXTR gene, 5-HTTLPR in SLC6A4 gene and rs6295 in the HTR1A gene. Self-assessed anxiety was measured by the State and Trait Anxiety Inventory (STAI) questionnaire.

Results

Self-assessed measure of both STAI-S and STAI-T were significantly higher in female than in male participants (p = 0.030 and p = 0.036, respectively). For SNP rs41423247 in the NR3C1 gene, there was a significant difference in females in the score for STAI-S, where carriers of the G allele had higher scores compared to the females that were homozygous for the C allele (p < 0.01). For the SNP rs53576 in the OXTR gene, there was a significant difference in males, where carriers of the A allele had higher scores in STAI-T compared to the males that were homozygous for the G allele (p < 0.01).

Conclusion

This study shows that SNP rs41423247 in the NR3C1 gene and SNP rs53576 in the OXTR gene are associated with self-assessed anxiety in healthy individuals in a gender-specific manner. This suggests that these SNP candidates are possible genetic risk-factors for anxiety.

The aim of this study was to investigate whether interacting with a visiting dog influences fingertip temperature and cortisol levels in residents living in nursing homes for the elderly. The study included two groups, the dog group (n = 13) and the control group (n = 11–15) and lasted for 8 weeks for the dog group and 6 weeks for the control group. All participants were residents living at nursing homes for the elderly. The researchers visited small groups of the participants twice weekly during the entire study in both the dog and the control group. The visiting dog and the dog handler accompanied the researchers during weeks 3–6. Fingertip temperature was measured and saliva samples for cortisol determination were collected at 0, 20 and 60 min for the dog group and at 0 and 20 min for the control group. For analysis the study was divided into periods; Period 1 (week 1–2), Period 2 (week 3–4), Period 3 (week 5–6) and Period 4 (week 7–8, only the dog group). Mean values based on all data obtained at 0 and 20 min during period 1–3 were compared between groups. A second, separate analysis for the dog group also included data from 60 min and for period 4. For the dog group fingertip temperature increased significantly between period 1 and 2, 1 and 3 and 1 and 4 (p < 0.05). In addition, fingertip temperature rose significantly between 0 and 20 min and between 0 and 60 min within all periods. For the control group a significant decrease in fingertip temperature was observed between period 1 and 3 (p < 0.05). Fingertip temperature did not differ between the two groups during period 1, but was significantly higher for the dog group than for the control group during periods 2 and 3 (p < 0.05 and p < 0.001, respectively). Cortisol results are only presented descriptively due to that many samples had too low volume of saliva to be analyzed. In the present study interaction between elderly residents and a visiting dog resulted in increased fingertip temperature, probably reflecting a decrease in the activity of the sympathetic nervous system and therefore a decrease in stress levels.

The positive clinical effects caused by skin-to-skin contact immediately after birth or after repeated skin-to-skin contact of premature infants (kangaroo care) or fullterm infants are well documented in the literature. However, information regarding the physiological mechanisms mediating these effects are surprisingly scarce and incomplete. In this article the oxytocinergic system and the cutaneous sensory pathways by which the oxytocinergic system is activated in response to skin-to-skin contact are presented in more detail. In addition, we discuss how the effects of skin-to-skin treatment can be attributed to different aspects of the effect spectrum of the oxytocinergic or calm and connection system.

The structure of the oxytocinergic system, comprising the peripheral (circulating, hormonal) and the central (neurotransmitter) components, as well as, the pathways and mechanisms by which these functions are coordinated are described. Also the various effects induced by the oxytocinergic system (the calm and connection system) are reviewed.

The sensory pathways, which include visual, auditory, olfactory and tactile stimuli, given and received by both mother and newborn and which activate the oxytocinergic system in response to skin-to-skin contact, are reviewed. A special emphasis is placed on the role of cutaneous sensory nerves and their activation by touch, light pressure and in particular warmth. The important role of the rise and the pulsatility of maternal temperature in mediating the positive effects of skin-to-skin contact in the newborn is highlighted. The concept of maternal giving of warmth and its possible link to the experience of trust and safety in the newborn is discussed from an evolutionary perspective.

The effects induced by skin-to-skin contact can be attributed to the different functions of the oxytocinergic system. Ameliorated social interaction (e.g., more tactile and auditory interaction, more sensitive and synchronous interaction between mother and baby, the baby’s crawling behavior) are expressions of oxytocin’s ability to stimulate social interaction. The decreased levels of fear and stress are expressions of oxytocin’s ability to reduce the activity of the amygdala and of the stress system, e.g. the activity in the HPA-axis and the sympathetic nervous system. Increased HRV, increased activity in endocrine system of the gastrointestinal tract as well as stimulation of growth and maturation are examples of oxytocin’s ability to stimulate the activity of the parasympathetic nervous system and other peripheral and central mechanisms related to restoration and growth.

The propensity of different types of treatment with skin-to-skin contact to induce long-term effects is also highlighted. We propose that the sustained effects caused by skin-to-skin contact are induced by an enduring shift in the balance between the oxytocinergic system (the calm and connection system) and the stress system (fight flight reaction) in favor of the oxytocinergic system. This shift leads to a sustained decrease in the HPA-axis and the sympathetic nervous system probably involving alpha 2-adrenoceptors.

It is of clinical importance to be aware of the mechanisms by which skin-to-skin contact induces short and longterm positive effects in parents and newborns. If ward routines are adapted to ascertain a maximal stimulation of these mechanisms, the function of the oxytocinergic system will be optimized, which will be linked to a better clinical outcome for parents and newborns.

Work-related stress is relatively common in modern society and is a major cause of sick-leave. Thus, effective stress reducing interventions are needed. This study examined the effects of mental training and mechanical massage, on employee's heart rate variability (HRV) and plasma cortisol at their workplaces. Moreover, it was investigated whether baseline systolic blood pressure (SBP) can explain differences in effectiveness of the intervention. Ninety-three participants from four workplaces were randomly assigned to one of the five programs: (I) Mechanical massage and mental training combined, II) Mechanical massage, III) Mental training, IV) Pause, or V) Control. HRV and plasma cortisol were measured at baseline and after 4 and 8 weeks. SBP was measured at baseline. On the reduction of cortisol levels, a small effect of the mechanical massage program was found, whereas no effect was found for the other programs. None of the programs showed any effect on HRV. Nonetheless, when the level of systolic blood pressure was taken into account, some small beneficial effects on HRV and cortisol of mental training and the mechanical massage were found. This exploratory pilot-study provides useful information for future studies that aim to reduce stress among employees. 

Oxytocin is a nonapeptide consisting of a cyclic six amino-acid structure and a tail of three amino acids. It was originally known for its ability to induce milk ejection and to stimulate uterine contractions. More recently, oxytocin has been shown to stimulate social behaviors, and exert pain-relieving, anti-stress/anti-inflammatory and restorative effects. We hypothesize that oxytocin is a principal hormone that, in part, exerts its effects after degradation to active fragments with more specific effect profiles. Experimental findings on rats show that administered oxytocin exerts biphasic effects. For example, after an initial increase in pain threshold, a second more long-lasting increase follows. Blood pressure and cortisol levels initially increase and then reverse into a long-lasting decrease in blood pressure and cortisol. Whereas the initial effects are, the second-phase effects are not blocked by an oxytocin antagonist, but by an opioid mu-antagonist and by an alpha 2-adrenoreceptor antagonist, respectively, suggesting that other receptors are involved. Repeated administration of oxytocin induces multiple anti-stress effects, which are mediated by alpha 2-adrenoreceptors. Repeated administration of linear oxytocin and linear oxytocin fragments with a retained C-terminal reduce spontaneous motor activity, a sedative or anti-stress effect, suggesting that alpha 2-adrenoreceptors have been activated. In contrast, linear mid-fragments stimulate motor activity. Low-intensity stimulation of cutaneous nerves in rats, as well as breastfeeding and skin-to-skin contact between mothers and babies, trigger immediate anti-stress effects. Some of these effects are likely caused by open ring/linear C-terminal fragments activating alpha 2-adrenoreceptors. Oxytocin fragments may be pre-formed and released in the brain or created by metabolic conversion of the principal hormone oxytocin in the central nervous system. Oxytocin and its fragments may also be released from peripheral sites, such as peripheral nerves, the gastrointestinal tract, and blood vessels in response to decreased sympathetic or increased parasympathetic nervous tone. Smaller fragments of oxytocin produced in the periphery may easily pass the blood-brain barrier to induce effects in the brain. In conclusion, oxytocin is linked to many different, sometimes opposite effects. The intact cyclic molecule may act to initiate social interaction and associated psychophysiological effects, whereas linear oxytocin and C-terminal fragments may induce relaxation and anti-stress effects following social interaction. In this way, the principal hormone oxytocin and its fragments may take part in a behavioral sequence, ranging from approach and interaction to calm and relaxation. Linear fragments, with an exposed cysteine-residue, may exert anti-inflammatory and antioxidant effects and thereby contribute to the health-promoting effects of oxytocin.