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Query: UNIPROT:P08908 (
5-HT1A
)
5,574
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
In mixed-sex rat groups consistent asymmetries in offensive and defensive behaviors of male dyads are associated with the development of dominance hierarchies. Subordinate males can be differentiated from dominants on the basis of both agonistic and non-agonistic behaviors, wound patterns, weight changes. Their behavior changes suggest chronic defensiveness and are also broadly isomorphic to many of the symptoms of depression; their voluntary alcohol consumption increases, and their life-spans are shortened. Both subordinate and dominant males tend to show organ change compared to non-grouped controls, with adrenal and spleen enlargement and
thymus
reduction. However, these changes appear to be more marked in subordinates, and only subordinates show reduced testes weights. Basal corticosterone (CORT) levels were sharply higher, and plasma testosterone (T) sharply lower, in subordinates compared to both dominants and controls, and reduced corticosterone binding globulin further enhanced free CORT for subordinates particularly. Many subordinates failed to show a normal CORT response to restraint stress. Subordinates also appear to show widespread changes in serotonin systems, with increased 5-HIAA/5-HT ratios in a number of brain areas, and alterations of
5-HT1A
receptor binding at some sites. These changes suggest that subordination, a common and consistent feature of life for many animals living in social groups, may be a particularly relevant model for investigating the behavioral, neural and endocrine correlates of chronic stress.
...
PMID:Subordination stress: behavioral, brain, and neuroendocrine correlates. 813 39
The effects of chronic corticosterone treatment (100 mg pellet implanted for 1 week) were assessed in animal tests of anxiety, exploration and motor activity, and changes in binding to
5-HT1A
and 5-HT2A receptors, and the 5-HT transporter, were measured. At the end of the week's treatment, the corticosterone concentration was significantly elevated and there were significant decreases in adrenal,
thymus
and body weights. However, there were no changes in the measures of anxiety in the social interaction test or on trials 1 and 2 of the elevated plus-maze. Also supporting a dissociation between anxiety and elevated corticosterone concentrations are previous findings that benzodiazepine withdrawal causes increased anxiety but no change in corticosteroid concentrations. Therefore these two situations provide a double dissociation between anxiety and elevated corticosteroids. Decreased
5-HT1A
receptor binding in the dentate gyrus and increased 5-HT2A receptor binding in the parietal cortex was found following chronic corticosterone treatment. This reciprocal relationship between
5-HT1A
and 5-HT2A receptors has been proposed to be important in mediating depression. The significant decreases in motor activity observed in all the test situations would be compatible with this proposal. Thus the constellation of behavioural and biochemical changes detected after chronic corticosterone treatment is more pertinent to depression than anxiety. One week after removal of the pellets, the behavioural and neurochemical changes had disappeared and the only differences to remain were decreased adrenal,
thymus
and body weights in the animals that had been treated chronically with corticosterone.
...
PMID:Decreased 5-HT1A and increased 5-HT2A receptor binding after chronic corticosterone associated with a behavioural indication of depression but not anxiety. 937 82
Social stress by repeated defeat has been shown to be endowed with neuroendocrine and behavioural effects that render this stress model useful to identify adaptive mechanisms. Among these mechanisms, those related to central serotonergic systems (e.g., hippocampal
5-HT1A
receptors, cortical 5-HT2A receptors) have been particularly underlined. Nonetheless, how (i) the neuroendocrine and behavioural effects of social stress are affected by the genetic status of the animal, and (ii) this status affects the relationships between central serotonergic systems and adaptive processes has not been studied so far. The present study has thus analysed the effects of repeated defeat (once a day for seven days) by Long-Evans resident rats upon the psychoneuroendocrine profile of Lewis rats and spontaneously hypertensive rats previously characterized for their contrasting social and anxiety-related behaviours. Repeated defeat decreased in a time-dependent manner, body weight growth and food intake in both strains, these decreases being, however, more severe and longer lasting in Lewis rats. This strain-dependent difference could not be accounted for by differences in physical contacts with the resident rats as the number of attacks and their latency throughout the stress period were similar between spontaneously hypertensive and Lewis rats. When exposed to an elevated plus-maze test of anxiety, the unstressed Lewis rats entered less the open arms than their spontaneously hypertensive counterparts, thus confirming that Lewis rats are more anxious than spontaneously hypertensive rats. This difference was amplified by stress as the latter increased anxiety-related behaviours in Lewis rats only. These strain- and stress-related differences were associated with differences in locomotor activity, this being increased in unstressed Lewis compared with spontaneously hypertensive rats; moreover, stress triggered hypolocomotion in the former but not the latter strain. Lastly, in the forced swimming test. Lewis rats spent more time immobile than spontaneously hypertensive rats with stress increasing immobility in a strain-independent manner. Beside the aforementioned metabolic changes, the activity of the hypothalamo-pituitary-adrenal axis was slightly stimulated in a strain-independent manner by the stressor, as assessed by increased corticosterone levels and adrenal weights, and decreased
thymus
weights. In Lewis, but not in spontaneously hypertensive rats, midbrain serotonin metabolism was increased by stress, a difference associated with an increased Bmax value of cortical [3H]ketanserin binding at 5-HT2A receptors. On the other hand, the Bmax value of hippocampal [3H]8-hydroxy-2-(di-n-propylamino)tetralin binding at
5-HT1A
receptors was decreased by stress, this reduction being amplified in spontaneously hypertensive compared with Lewis rats. This study shows that the psychoneuroendocrine responses to social stress may have a genetic origin, and that the use of socially stressed Lewis and spontaneously hypertensive rats may provide an important paradigm to study adaptive processes. However, whether the aforementioned strain-dependent differences in central serotonergic systems (partly or totally) underlie the distinct profiles of emotivity measured in spontaneously hypertensive and Lewis rats, is discussed in the context of the relationships between serotonergic systems and behavioural responses to novel environments.
...
PMID:Differential effects of social stress on central serotonergic activity and emotional reactivity in Lewis and spontaneously hypertensive rats. 948 11
Serotonin (5-hydroxytryptamine, 5-HT) has been shown to play a role in immunoregulation; however, little is known about specific subtypes of 5-HT receptors involved in peripheral immunomodulation. In the present study we used RT-PCR methods to examine the mRNA expression of 5-HT receptors in the cells of lymphoid tissues of the rat. All 13 rat 5-HT receptor genes cloned so far were examined in ex vivo isolated spleen,
thymus
, and peripheral blood lymphocytes, as well as in mitogen-stimulated spleen cells. Positive signals were obtained for 5-HT1B, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT6, and 5-HT7 receptor mRNAs in all three compartments. Mitogen (ConA and PWM) stimulated cells additionally expressed mRNA corresponding to the 5HT-3 receptor subtype. In contrast,
5-HT1A
, 5-HT1D, 5-HT2C, 5-HT4, 5-HT5A, and 5-HT5B mRNAs were not detected in any of the examined cell populations. These results may be useful as a starting point for future functional studies on immunomodulatory effects of 5-HT and may help to understand conflicting serotonergic effects on immune functions as found in the literature.
...
PMID:mRNA expression of serotonin receptors in cells of the immune tissues of the rat. 1097 Jun 81