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1.
Genetic variation at a single nucleotide polymorphism (SNP) in the mu-opioid receptor gene (OPRM1) of both humans and rhesus macaques Macaca mulatta has been associated with differential affinity to the endogenous ligand beta-endorphin as well as alterations in pain sensitivity, drug and alcohol dependence, and social behaviors. The new study by Higham et al. (2011) presented in the current issue of this journal shows for the first time that some of the natural variation in maternal behavior observed in rhesus macaque populations can also be explained by genetic differences at this SNP. This work, in conjunction with other recent studies showing that genetic variability at this same locus are related to changes in infant attachment, provides unique insights into how opioids have been reutilized during evolution to coordinate the mother-infant relationship.  相似文献   

2.
Hypertension and risk for hypertension have been associated with reduced pain sensitivity. It has been hypothesised that endogenous opioids contribute to this hypertensive hypoalgesia. The nociceptive flexion reflex can be used as a tool to investigate modulation of nociceptive transmission at spinal level. The current study employed a double-blind placebo-controlled design to compare the effects of naltrexone, an opioid antagonist, and placebo on nociceptive flexion reflex thresholds and nociceptive responding in unmedicated patients with essential hypertension and normotensive individuals. Neither nociceptive flexion reflex thresholds nor nociceptive responding differed between hypertensives and normotensives during placebo or naltrexone. These data provide no support for the hypothesis that essential hypertension is characterised by higher levels of endogenous opioids in the central nervous system and reveal no association between blood pressure status and nociceptive flexion reflex responses.  相似文献   

3.
L Sher 《Medical hypotheses》2001,57(5):609-611
Skin cells produce endogenous opioids in response to light. This results in increased skin and plasma levels of endogenous opioids. Increased plasma levels of endogenous opioids may improve mood and affect behavior. The author suggests that improvement in mood after exposure to light may be related to the light-induced increase in levels of endogenous opioids. The author speculates that genetic factors may affect the response of skin cells to light: different people may have different genetically determined responses to natural or artificial light. The author also suggests that light may affect endogenous opioids via several different mechanisms.  相似文献   

4.
Essential hypertension is characterised by reduced pain sensitivity. Hypertensive hypoalgesia has been attributed to elevated endogenous opioids and/or increased activation of descending pain modulation systems. A double-blind placebo-controlled design compared the effects of naltrexone and placebo on cold and ischemic pain in unmedicated newly-diagnosed patients with essential hypertension. Patients performed a cold pressor task while resting and while performing a distracting secondary task. They also performed a forearm ischemia task while resting. Although the cold pressor and ischemia tasks elicited significant increases in pain and blood pressure, pain ratings and pressor responses did not differ between naltrexone and placebo. Cold pain was reduced by distraction compared to rest. The finding that opioid blockade with naltrexone did not moderate the pain and pressor responses to cold and ischemia suggests that pain and associated blood pressure responses are not modulated by opioids in hypertension. The finding that the distracting secondary task successfully reduced pain ratings suggests normal supraspinal pain modulation in essential hypertension.  相似文献   

5.
Anger management style is related to both acute and chronic pain. Recent research suggests that individuals who predominantly express anger (anger-out) may report heightened chronic pain severity due in part to endogenous opioid antinociceptive dysfunction. If exogenous opioids serve to remediate opioid deficits, we predicted that regular use of opioid analgesics by chronic pain patients would alter these relationships such that anger-out would be related to chronic pain severity only among opioid-free patients. For 136 chronic pain patients, anger management style, depression, anxiety, pain severity, and use of opioid and antidepressant medication was assessed. Results of hierarchical multiple regressions to predict chronic pain severity showed: (a) a significant Anger-out × Opioid use interaction such that high Anger-out was associated with high pain severity only among patients not taking opioids; (b) controlling for depressed affect and anxiety did not affect this association; (c) the Anger-out × Antidepressant use interaction was nonsignificant; (d) Anger-in did not interact with use of any medication to affect pain severity. Results are consistent with an opioid-deficit hypothesis and suggest that regular use of opioid medications by patients high in anger expression may compensate for an endogenous opioid deficit, and mitigate the effects of elevated anger expression on chronic pain intensity.  相似文献   

6.
This study examined the relationship among endogenous opioids, Monitoring and Blunting coping styles, and acute pain responses. Fifty-eight male subjects underwent a 1-min pressure pain stimulus during two laboratory sessions. Subjects experienced this pain stimulus once under endogenous opioid blockade with naltrexone and once in a placebo condition. Blunting was found to be negatively correlated with pain ratings, but this relationship was significantly more prominent under opioid blockade. Results for coping behaviors subjects used to manage the experimental pain were generally consistent with the Blunting results, indicating that cognitive coping was related more strongly to decreased pain ratings and cardiovascular stress responsiveness under opioid blockade. Overall, the beneficial effects of Blunting and cognitive coping on pain responses did not depend upon endogenous opioids and, in fact, became stronger when opioid receptors were blocked. The relationship between endogenous opioids and coping appears to be dependent upon situational and stimulus characteristics.  相似文献   

7.
In adolescent rats, 50-kHz vocalizations are most evident during tickling and rough-and-tumble play. The following experiments evaluated whether 50-kHz vocalizations reflect positive social affect by determining (1) if tickling is a rewarding event, (2) if social or isolate housing conditions differentially influence the response (since housing condition has been found to effect the reward magnitude of social encounters), and (3) if drugs that work on mu-opiate receptors, which has been hypothesized to control positive social affect, modulate tickling. Tickling was positively reinforcing as demonstrated by elevated operant behavior, conditioned place preference, and approach measures. A significant negative correlation between vocalization rate and approach latency measures was found. Social housing reduced tickle-induced vocalizations and approach speeds compared to isolate housing. Naloxone (1 mg/kg) increased vocalization in the socially housed rats and decreased it in isolated Subjects (Ss). These findings suggest that tickling can be used to induce positive social affect in rodents, and that it is modulated by endogenous opioids.  相似文献   

8.
The degree to which related individuals exhibit cooperative, aid-giving behavior varies interspecifically among the ground-dwelling sciuridae, and the use of particular mechanisms to mediate kin recognition has been predicted to vary accordingly. Recent studies of kin recognition mechanisms in Spermophilus indicate that both mother-offspring and sibling recognition is facilitated by familiarity established during early association and that odor is the most probable cue on which discriminations are based. In three of four species, empirical evidence suggests that phenotype matching and/or recognition alleles can supplement the familiarity effects for siblings. This interspecific variation is discussed in terms of (1) differential occurrence of the contexts proposed to promote phenotype matching, (2) differential opportunities for implementing discriminations of various classes of relatives, and (3) differential selection for channeling preferential treatment toward genetic relatives. Although the observed variation appears to be consistent with 3 and perhaps 2, the assumption that the mechanisms used in recognizing particular classes of relatives are ontogenetically stable and species typical is questioned.  相似文献   

9.
Quantitative trait locus mapping of chemical/inflammatory pain in the mouse identified the Avpr1a gene, which encodes the vasopressin-1A receptor (V1AR), as being responsible for strain-dependent pain sensitivity to formalin and capsaicin. A genetic association study in humans revealed the influence of a single nucleotide polymorphism (rs10877969) in AVPR1A on capsaicin pain levels, but only in male subjects reporting stress at the time of testing. The analgesic efficacy of the vasopressin analog desmopressin revealed a similar interaction between the drug and acute stress, as desmopressin inhibition of capsaicin pain was only observed in nonstressed subjects. Additional experiments in mice confirmed the male-specific interaction of V1AR and stress, leading to the conclusion that vasopressin activates endogenous analgesia mechanisms unless they have already been activated by stress. These findings represent, to the best of our knowledge, the first explicit demonstration of analgesic efficacy depending on the emotional state of the recipient, and illustrate the heuristic power of a bench-to-bedside-to-bench translational strategy.  相似文献   

10.
Prenatal morphine treatment and emotional stress both have been shown to increase sensitivity to reward-related behaviors. It has been postulated that this increased sensitivity to rewarding stimuli may be the result of an enhanced release of endogenous opioids. In the present study, in vivo autoradiography was employed to investigate the endogenous opioid release in specific brain areas in rats. Pregnant animals were exposed to morphine or saline from day 8 of gestation till birth. Development of pups was monitored and play behavior was tested on postnatal day 21. Adult rats were exposed to repeated emotional stress or control treatment for five consecutive days and tested in a small open field 5 days later. [3H]-Diprenorphine was injected following this test to investigate endogenous opioid release.  相似文献   

11.
Greater dispositional optimism has been related to less severe pain; however, whether optimism is associated with endogenous pain modulation has not yet been examined. The beneficial effects of dispositional optimism often vary according to cultural dynamics. Thus, assessing optimism–pain relationships across different ethnic groups is warranted. This study sought to examine the association between optimism and conditioned pain modulation (CPM), and test whether this association differs according to ethnicity. Optimism and CPM were assessed in a sample of healthy, ethnically diverse young adults. CPM was determined by comparing pressure pain thresholds obtained before and during exposure to a cold pressor task. All participants completed a validated measure of dispositional optimism. Greater reported optimism was significantly associated with enhanced CPM, and the strength of this association did not vary according to individuals’ ethnic background. These findings suggest that an optimistic disposition may potentiate endogenous pain inhibition.  相似文献   

12.
The current study tested the hypothesis that conditioned pain modulation is mediated by the release of endogenous opioids with a placebo-controlled (sugar pill) study of naltrexone (50 mg) in 33 healthy volunteers over two counter-balanced sessions. Pain modulation consisted of rating of heat pain (palm) during concurrent cold water immersion (foot). Compared to baseline heat pain ratings, concurrent foot immersion lowered pain intensity ratings, which suggests an inhibitory effect, was reduced with naltrexone, suggesting at least partial dependence of inhibition on endogenous opioids. An exploratory analysis revealed that individual differences in catastrophizing moderated the effects of naltrexone; endogenous opioid blockade abolished modulation in subjects lower in catastrophizing while modulation was unaffected by naltrexone among high catastrophizers. The results suggest a role of endogenous opioids in endogenous analgesia, but hint that multiple systems might contribute to conditioned pain modulation, and that these systems might be differentially activated as a function of individual differences in responses to pain.  相似文献   

13.
《Explore (New York, N.Y.)》2023,19(3):362-370
ObjectivesYoga is an increasingly popular mode of exercise that boasts health promoting effects including pain relief. A single bout of exercise induces a reduced sensitivity to noxious heat, but the mechanism for this effect and whether it occurs after a single session of yoga is unexplored. The primary aim of this study was to test, using a post-test only between-subjects design, main and interactive effects of yoga and slow breathing on both sensitivity to heat pain and endogenous pain modulation processing in healthy young womenDesignFifty-four women were block randomized into one of four conditions: yoga with slow breathing instructions (Vinyasa), yoga with no breathing instructions, seated rest with slow breathing instructions and seated rest with no breathing instructions. The conditions were completed alone is a small room in which participant followed video-based instructions and models. The yoga was perceived as low-to-moderate intensity.ResultsTwo factor ANOVA demonstrated no significant association between yoga postures and slow breathing, and there was no significant interaction observed for sensitivity to heat pain or endogenous pain modulation. These findings were unchanged in ANCOVAs that controlled for four potential confounding variables: post-condition reduction in systolic blood pressure or state anxiety, pain induced by the conditions and expectations. Compared to the non-yoga conditions, participant in yoga conditions resulted in a significant reduction in state anxiety scores.ConclusionsIt is concluded that a single session of low-to-moderate intensity yoga with, or without slow breathing, reduces state anxiety but has no effect on heat pain sensitivity or endogenous pain modulation.  相似文献   

14.
Ten-day-old rats, for whom an orange scent predicted morphine injections at 5 days of age, exhibited a marked preference for orange that was fully naltrexone reversible. Moreover, such rats, when smelling orange during a heat-escape task, exhibited a higher pain threshold than control rats. Together, these findings suggest that the orange odor in conditioned rats caused a release of endogenous opioids that both sustained choice behavior and modulated pain systems.  相似文献   

15.
The involvement of endogenous morphines (enkephalins and endorphins) in the regulation of pain is demonstrated by the following experimental evidence: (a) their analgesic activities; (b) their distribution in the central nervous systems; (c) the effects of their modifiers, especially of their antagonists, on nociceptive reactions and (or) on various types of analgesia; (d) rare modifications of their brain levels in paid and (or) analgesic states. Besides the well-known facts, the following items are particularly stressed: the functional roles of hypothalamic structures and of the pituitary, the effects of antagonists, the variety of analgesia following noxious and (or) stressful stimuli, genetic and environmental factors, endogenous antinociceptive substances other than opioids, relations with biogenic amines. As a whole, endogenous morphines apparently filter the particular important sensory input represented by nociception and control the reactions to pain, allowing for adjusted behaviour, if the stimuli are avoidable, or for prevention or at least delay of exhaustion if the stimuli are unavoidable.  相似文献   

16.
Evidence that gene×environment interactions can reflect differential sensitivity to the environmental context, rather than risk or resilience, is increasing. To test this model, we examined the genetic contribution to indiscriminate social behavior, in the setting of a randomized controlled trial of foster care compared to institutional rearing. Children enrolled in the Bucharest Early Intervention Project (BEIP) were assessed comprehensively before the age of 30 months and subsequently randomized to either care as usual (CAUG) or high quality foster care (FCG). Indiscriminate social behavior was assessed at four time points, baseline, 30 months, 42 months and 54 months of age, using caregiver report with the Disturbances of Attachment Interview (DAI). General linear mixed-effects models were used to examine the effect of the interaction between group status and functional polymorphisms in Brain Derived Neurotrophic Factor (BDNF) and the Serotonin Transporter (5htt) on levels of indiscriminate behavior over time. Differential susceptibility, relative to levels of indiscriminate behavior, was demonstrated in children with either the s/s 5httlpr genotype or met 66 BDNF allele carriers. Specifically children with either the s/s 5httlpr genotype or met66 carriers in BDNF demonstrated the lowest levels of indiscriminate behavior in the FCG and the highest levels in the CAUG. Children with either the long allele of the 5httlpr or val/val genotype of BDNF demonstrated little difference in levels of indiscriminate behaviors over time and no group×genotype interaction. Children with both plasticity genotypes had the most signs of indiscriminate behavior at 54 months if they were randomized to the CAUG in the institution, while those with both plasticity genotypes randomized to the FCG intervention had the fewest signs at 54 months. Strikingly children with no plasticity alleles demonstrated no intervention effect on levels of indiscriminate behavior at 54 months. These findings represent the first genetic associations reported with indiscriminate social behavior, replicate previous gene×gene×environment findings with these polymorphisms, and add to the growing body of literature supporting a differential susceptibility model of gene×environment interactions in developmental psychopathology.  相似文献   

17.
Pain severity ratings and the analgesic dosing requirements of patients with apparently similar pain conditions may differ considerably between individuals. Contributing factors include those of genetic and environmental origin with epigenetic mechanisms that enable dynamic gene-environment interaction, more recently implicated in pain modulation. Insight into genetic factors underpinning inter-patient variability in pain sensitivity has come from rodent heritability studies as well as familial aggregation and twin studies in humans. Indeed, more than 350 candidate pain genes have been identified as potentially contributing to heritable differences in pain sensitivity. A large number of genetic association studies conducted in patients with a variety of clinical pain types or in humans exposed to experimentally induced pain stimuli in the laboratory setting, have examined the impact of single-nucleotide polymorphisms in various target genes on pain sensitivity and/or analgesic dosing requirements. However, the findings of such studies have generally failed to replicate or have been only partially replicated by independent investigators. Deficiencies in study conduct including use of small sample size, inappropriate statistical methods and inadequate attention to the possibility that between-study differences in environmental factors may alter pain phenotypes through epigenetic mechanisms, have been identified as being significant.  相似文献   

18.
Cues used in the discrimination of relatives from nonrelatives by the honey bee reflect both genetic and environmental differences between groups. Discrimination is behaviorally expressed by acceptance into or agonistic rejection from the social group. We examine the development of these cues in field colonies and in controlled laboratory settings. Newly emerged worker honey bees are accepted by honey bee social groups at a high frequency. When bees are kept in a controlled laboratory environment for 5 days, acceptability into laboratory groups is determined largely by relatedness. Cues indicating relatedness develop in the laboratory within 12 h after the adult bee emerges. Bees older than 12 h are not accepted by field colonies regardless of relatedness. Bees maintained in a hive until 5 days after emergence are not accepted by related or unrelated laboratory groups (this is termed the hive effect). Bees maintained in hives for times as short as 5 h acquired the hive effect. In a cross-fostering experiment, the hive effect completely masked genetic differences.This work was supported by NSF Grants BNS 82-16787 and BNS 86-05604.  相似文献   

19.
Social genetics     
Most behavior is expressed within social systems, and the genetic analysis of its variance therefore presents theoretical and technical problems that have been sidestepped in most previous research. The dog presents obvious advantages for studying behavioral interactions between genotypes. Two sets of data are summarized that indicate that the magnitude of genetic differences is related to the differentiation of social roles in a competitive situation, whereas similarity of genotypes is an advantage in a situation demanding coordinated activity. Issues concerning the use of correlational techniques to study social behavior are raised.Presidential address to the Behavior Genetics Association on the occasion of the Sixth Annual Meeting, Boulder, Colorado, June 17–19, 1976.  相似文献   

20.
Previously we and others have shown evidence for genetic influences on political attitudes and sociodemographic indicators (Martin 1987; Posner et al. 1996; Truett et al. 1992; Eaves et al. 1999). However, the nature of the relationship between political attitudes, social indictors and voting behavior has not been investigated. While heritability estimates for social and political attitudes have been reported in previous research, the heritability for vote choice has not. Furthermore, if vote choice is heritable, it is unclear whether the heritable component can be accounted for through the genetic influence on related social and political traits, or if there exists a unique genetic component specific to voting behavior. In mailed surveys of adult Australian twins, we asked respondents to indicate their usual voting preference as well as attitudes on contemporary individual political items. When vote choice was dichotomized as Labor versus Conservative, twin correlations were r (mz) = 0.81 (1,661 pairs), and r (dz) = 0.69 (1,727 pairs) consistent with modest genetic influence (a (2) = 0.24). However, multivariate genetic analysis showed no unique genetic contribution to voting preference; rather, the genetic influence in vote choice could be explained by shared genetic influences in perceived social class, church attendance and certain key political attitude items.  相似文献   

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