The protective effects of social bonding on behavioral and pituitary-adrenal axis reactivity to chronic mild stress in prairie voles.

Positive social interactions may protect against stress. This study investigated the beneficial effects of pairing with a social partner on behaviors and neuroendocrine function in response to chronic mild stress (CMS) in 13 prairie vole pairs. Following 5 days of social bonding, male and female prairie voles were exposed to 10 days of CMS (mild, unpredictable stressors of varying durations, for instance, strobe light, white noise, and damp bedding), housed with either the social partner (paired group) or individually (isolated group). Active and passive behavioral responses to the forced swim test (FST) and tail-suspension test (TST), and plasma concentrations of adrenocorticotropic hormone (ACTH) and corticosterone, were measured in all prairie voles following the CMS period. Both female and male prairie voles housed with a social partner displayed lower durations of passive behavioral responses (immobility, a maladaptive behavioral response) in the FST (mean ± SEM; females: 17.3 ± 5.4 s; males: 9.3 ± 4.6 s) and TST (females: 56.8 ± 16.4 s; males: 40.2 ± 11.3 s), versus both sexes housed individually (females, FST: 98.6 ± 12.9 s; females, TST: 155.1 ± 19.3 s; males, FST: 92.4 ± 14.1 s; males, TST: 158.9 ± 22.0 s). Female (but not male) prairie voles displayed attenuated plasma stress hormones when housed with a male partner (ACTH: 945 ± 24.7 pg/ml; corticosterone: 624 ± 139.5 ng/ml), versus females housed individually (ACTH: 1100 ± 23.2 pg/ml; corticosterone: 1064 ± 121.7 ng/ml). These results may inform understanding of the benefits of social interactions on stress resilience. Lay Summary: Social stress can lead to depression. The study of social bonding and stress using an animal model will inform understanding of the protective effects of social bonds. This study showed that social bonding in a rodent model can protect against behavioral responses to stress, and may also be protective against the elevation of stress hormones. This study provides evidence that bonding and social support are valuable for protecting against stress in humans

Politics ahead of patients: The battle between medical and chiropractic professional associations over the inclusion of chiropractic in the American Medicare System

Health care professions struggling for legitimacy, recognition, and market share can become disoriented to their priorities. Health care practitioners are expected to put the interests of patients first. Professional associations represent the interests of their members. So when a professional association is composed of health care practitioners, its interests may differ from those of patients, creating a conflict for members. In addition, sometimes practitioners’ perspectives may be altered by indoctrination in a belief system, or misinformation, so that a practitioner could be confused about the reality of patient needs. Politicians, in attempting to find an expedient compromise, can value a “win” in the legislative arena over the effects of that legislation. These forces all figure into the events that led to the acceptance of chiropractic into the American Medicare system. Two health care systems in a political fight lost sight of their main purpose: to provide care to patients without doing harm. Dans leur recherche de légitimité, de reconnaissance et d’une juste part sur le marché de la santé, les professionnels de la santé peuvent perdre de vue leurs priorités. Ces praticiens doivent donner préséance aux intérêts des patients tandis que les associations professionnelles représentent ceux de leurs membres. Lorsqu’une association professionnelle regroupe des praticiens de la santé cependant, ses intérêts s’opposent parfois à ceux des patients, créant ainsi un conflit pour les membres. De plus, les praticiens peuvent être endoctrinés par un système de valeurs ou mal informés, au point de se tromper dans l’évaluation des besoins réels des patients. De leur côté, les politiciens peuvent préférer une « victoire » dans l’arène législative à une juste appréciation des impacts d’une loi. Ces forces ont toutes participé aux évènements qui ont mené à l’acceptation de la chiropraxie par le système américain Medicare. Dans cette bataille politique, deux systèmes de santé ont négligé leur principal objectif : soigner des patients sans leur nuire

Enhancement of vicarious stress through prior established bond : determining the role of the arginine vasopressin 1a receptor

Advisors: Angela J. Grippo.Committee members: Mitrick Johns; Leslie Matuszewich; Alan Rosenbaum; Brad Sagarin; Lin Shi; Douglas Wallace.Includes bibliographical references.Includes illustrations.The experience of stress can have profoundly negative effects on overall psychological and physiological health. It is also true that in social species, interactions with others can have the power to either ameliorate or potentiate these effects. As both stress levels and social interconnectedness rise within our world, it becomes imperative for science to better understand the interactions between stress and the social environment. In support of this goal, the purpose of the current study was to investigate whether a prior established bond between two social animals enhances the physiological and behavioral response to stress in a bonded partner that does not directly experience a stressor, but rather observes another animal directly experience the stressor in an extremely social species, the prairie vole (Microtus ochrogaster ). The current study also examined a possible neural mechanism that could mediate the vicarious stress response and allow for such a vicarious stress enhancement to occur. The focus of this investigation is the nonapeptide arginine vasopressin (AVP), which is one of several chemicals that are released when an organism experiences stress. This chemical helps an organism cope with a stressor assisting in the ultimate increase in heart rate, blood pressure, and the amount of energy available in the blood. These functions occur through stimulation of numerous subtypes of AVP receptors that are located throughout the body, performing various functions depending on the type and location of the receptor. Interestingly, this chemical has also been shown to play a vital role in other social and cognitive functions, such as enhancing bonding ability, and increasing social recognition and memory. It was hypothesized that AVP is released in organisms when they experience a stressor, even when the organism in question experiences the stressor indirectly, or vicariously, through observing another organism directly experience a stressor, and that if a prior bond exists between the two animals in question, the stress response in an observer animal will be elevated when compared to animals that are unknown to each other. Furthermore, we hypothesized that this enhancement of vicarious stress occurs because AVP that is released during the vicarious experience of stress inadvertently stimulates the AVP receptors in the brain that are responsible for "reminding" the observer animal about the prior established bond between the observer and the target. Therefore, when a prior bond exists between the two animals, the stress response of the observer is elevated due to the increased salience of the event, creating a positive feedback loop, ultimately resulting in a net increase in physiological arousal in the observer. Results of the current study failed to support either of these hypotheses however, with no statistically significant differences in any of the key dependent measures of stress response activation observed. However, secondary analyses provided evidence for no habituation and even a slight sensitization to the testing apparatus during the acclimation period of the experiment in this species, which is in stark contrast to other species of rodent. Because no habituation to the testing apparatus occurred, actual differences in stress response activation may have been obscured in the "noise" of novel stimulus stress. This information provides a framework for the future development of testing paradigms to address this issue, resulting in the ability to draw stronger conclusions. A better understanding of vicarious stress and possible mediating mechanisms might help to explain and prevent the spread of stress in dyadic relationships, as well as within other social groups. Extension of the current research will also provide a possible explanation (through individual variation of the specific AVP receptor studied) that may help to elucidate why some people are more susceptible to the negative effects of vicarious stress than others, and provide a possible pharmacological target that could be utilized to protect the stress experienced by one member of a dyadic relationship (i.e. depression, work stress) from harming those closest to them.Ph.D. (Doctor of Philosophy

Social isolation and oxytocin antagonism increase emotion-related behaviors and heart rate in female prairie voles

Social isolation influences depression- and anxiety-related disorders and cardiac function. Oxytocin may mediate these conditions through interactions with social behavior, emotion, and cardiovascular function, via central and/or peripheral mechanisms. The present study investigated the influence of oxytocin antagonism using L-368,899, a selective oxytocin receptor antagonist that crosses the blood-brain barrier, on depression- and anxiety-related behaviors and heart rate in prairie voles. This rodent species has translational value for investigating interactions of social stress, behavior, cardiac responses, and oxytocin function. Adult female prairie voles were socially isolated or co-housed with a sibling for 4 weeks. A subset of animals in each housing condition was subjected to 4 sessions of acute L-368,899 (20 mg/kg, ip) or saline administration followed by a depression- or anxiety-related behavioral assessment. A subset of co-housed animals was evaluated for cardiac function following acute administration of L-368,899 (20 mg/kg, ip) and during behavioral assessments. Social isolation (vs. co-housing) increased depression- and anxiety-related behaviors. In isolated animals, L-368,899 (vs. vehicle) did not influence anxiety-related behaviors but exacerbated depression-related behaviors. In co-housed animals, L-368,899 exacerbated depression-related behaviors and increased heart rate at baseline and during behavioral tests. Social isolation produces emotion-related behaviors in prairie voles; central and/or peripheral oxytocin antagonism exacerbates these behavioral signs. Oxytocin antagonism induces depression-relevant behaviors and increases basal and stressor-reactive heart rate in co-housed prairie voles, similar to the consequences of social isolation demonstrated in this model. These results provide translational value for humans who experience behavioral and cardiac consequences of loneliness or social stress