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Biomedical subjects

Y Ago

Publications and source records attributed to Y Ago.

At least 19 recordsLinked to original sources
PubMed2002

Selective reduction by isolation rearing of 5-HT1A receptor-mediated dopamine release in vivo in the frontal cortex of mice.

Serotonin (5-HT)1A receptors modulate in vivo release of brain monoaminergic neurotransmitters which may be involved in isolation-induced aggressive behavior. The present study examined the effect of isolation rearing on the 5-HT1A receptor-mediated modulation of dopamine (DA), 5-HT and noradrenaline (NA) release in the frontal cortex of mice. The selective 5-HT1A receptor agonist (S)-5-[-[(1,4-benzodioxan-2-ylmethyl)amino]propoxy]-1,3-benzodioxole HCl (MKC-242) increased the release of DA and NA and decreased the release of 5-HT in the frontal cortex of mice. The effect of MKC-242 on DA release was significantly less in isolation-reared mice than in group-reared mice, while effects of the drug on NA and 5-HT release did not differ between both groups. The effect of the other 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin on cortical DA release was also less in isolation-reared mice than in group-reared mice, and that of the drug on cortical 5-HT release did not differ between both groups. In contrast to MKC-242-induced DA release, amphetamine-induced increase in cortical DA release in vivo was greater in isolation-reared mice. The present findings suggest that isolation rearing enhances the activity of cortical dopaminergic neurons and reduces selectively the 5-HT1A receptor-mediated release of DA in the cortex.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2001

Involvement of benzodiazepine binding sites in an antiaggressive effect by 5-HT(1A) receptor activation in isolated mice.

The effect of the benzodiazepine receptor antagonist flumazenil was examined on an antiaggressive effect of (S)-5-[3-[(1,4-benzodioxan-2-ylmethyl)amino]propoxy]-1,3- benzodioxole HCl (MKC-242), a 5-HT(1A) receptor agonist. MKC-242 (0.1-1.0 mg/kg, p.o.) selectively reduced isolation-induced aggressive behavior in a dose-dependent manner. Flumazenil (10 mg/kg, i.p.) antagonized the antiaggressive effects of MKC-242 and diazepam, although it alone did not affect the behaviors of isolated mice. These findings suggest that a gamma-aminobutyric acid(A) (GABA(A)) receptor system is involved in the antiaggressive effect by 5-HT(1A) receptor activation.

Aggression↗
PubMed2001

Functional alteration of brain dopaminergic system in isolated aggressive mice.

The present study examined the effects of social isolation on cortical dopamine (DA) release in vivo and on brain DA receptor functions to study the possible involvement of cortical DA neurons in an antiaggressive effect of the serotonin (5-HT)1A receptor agonist (S)-5-[3-[(1,4-benzodioxan-2-ylmethyl)amino] propoxy]-1,3-benzodioxole HCl (MKC-242). MKC-242 and the DA receptor agonist apomorphine reduced aggressive behavior in isolated mice. MKC-242 increased cortical DA release in vivo in mice, and the effect was antagonized by the 5-HT1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide. The basal level of extracellular DA in the frontal cortex was higher in isolated mice than in grouped mice. MKC-242-induced and high K(+)-induced increases in the cortical DA release were less pronounced in isolated mice than in grouped mice. The effect of apomorphine on locomotor activity was more pronounced in isolated mice than in grouped mice. These findings suggest that the isolation stress enhances cortical DA release and the brain DA receptor function and reduces the responses of the dopaminergic terminals to 5-HT1A receptor stimulation and high K(+)-induced depolarization.

Aggression↗
PubMed2000

Pituitary-adrenocortical responses to the first dyadic encounters in male rhesus monkeys: effect of dominance relationship.

Male rhesus monkeys unfamiliar with each other were paired in a cage, and blood samples were collected before and a few hours after pair formation. Adrenocorticotrophic hormone (ACTH) and cortisol levels in each blood sample were measured. Dominant-subordinate status was ascertained through two rank tests, the food competition test and the agonistic behavior test, which were performed immediately after pair formation. As a result, the dominance relationship was determined in seven pairs formed from five animals, and the differences in ACTH and cortisol values between the dominant and subordinate animal in these pairs were compared statistically. The day after the first encounter, a second encounter was conducted in randomly selected pairs of monkeys. In the first encounters, higher levels of both ACTH and cortisol were detected in dominant animals in comparison to subordinate animals. Changing the animal's partner altered the stress responses whenever the animal's dominant-subordinate status changed. The elevated levels of ACTH and cortisol in dominant animals disappeared on the day after the first encounter. In dominant animals, the pituitary-adrenocortical stress response reacts sharply to situational demands, whereas subordinate animals have a weaker response. This acute stress response is different from a chronic stress response. When the subordinate animal cannot escape, its hypothalamic-pituitary-adrenocortical axis appears to be suppressed.

Adrenocorticotropic Hormone↗
PubMed1997

Decreased cytotoxic lymphocyte counts in alexithymia.

BACKGROUND: Alexithymia is a psychological trait characterized by a difficulty in verbalizing feelings, which has been associated with a number of illnesses, including bronchial asthma and cancer. METHODS: In order to understand how psychological variables such as alexithymia affect physical health, we compared the lymphocyte subsets of men (n = 97, mean 30.6) rated as high and low alexithymic when measured by the Toronto Alexithymia Scale (TAS). We analyzed our data by considering alexithymia a categorical variable, using TAS scores of 62 and below, and 74 and above, and by considering alexithymia a continuous variable, using the mean TAS score (64.01) separating high from low alexithymia. RESULTS: When alexithymia was considered a categorical variable, highly alexithymic men had significantly lower numbers of the most cytotoxic natural killer (NK) subset, (CD57-CD16+ cells). When alexithymia was considered a continuous variable, in addition to the NK subset, killer effector T cell (CD8+CD11a+ cells) count was also significantly lower. These results were obtained after controlling for possible effects of smoking and alcohol intake. CONCLUSIONS: These results suggest that the negative modulation of cellular immunity, especially the cytotoxic lymphocytes, may be one mechanism which, combined with other factors that have a negative effect on the immune system such as stress, results in the association between alexithymia and ill health. It is suggested that future studies should, in addition to cell counts, attempt to identify the effects of psychological variables on the cytolytic activity of cytotoxic lymphocytes. Furthermore, follow-up studies should monitor the subjects over the years to demonstrate that alexithymia-mediated negative modulation of the immune system results in clinical pathologies.

Adult↗
PubMed1997

Sleep characteristics of Japanese working men who score alexithymic on the Toronto Alexithymia Scale.

This study examined the relationship of sleep characteristics including insomnia with scores on alexithymia in a sample of 171 Japanese working men. Levels of nonrestorative sleep and daytime sleepiness reported on a sleep questionnaire were significantly associated with scores on Depression and Confusion on the Profile of Mood States for Japanese men who had a high mean score on the Toronto Alexithymia Scale.

Adaptation, Psychological↗
PubMed1997

Mothers' low care in the development of alexithymia: a preliminary study in Japanese college students.

We examined the influences of perceived parental bonding on scores on alexithymia in a sample of 232 college students. Ratings on mothers' care, a scale of the Parental Bonding Inventory were significantly and negatively correlated with scores on the Toronto Alexithymia Scale, and also with ratings on Difficulty Describing Feelings but not Difficulty Identifying Feelings and Externally Oriented Thinking. These results were replicated in another sample of 156 college students. Although our findings were based on simple correlations, they suggest that perceived mothers' low care is related to adults' scores on alexithymia, in particular, the construct, Difficulty Describing Feelings.

Adolescent↗
PubMed1996

Acute electrical stimulation of lateral hypothalamus increases natural killer cell activity in rats.

Natural killer cell (NK) activity in WKA and SD rats was found to be significantly higher following electrical stimulation of the lateral hypothalamus (LH) compared to sham operated. There was no such difference between sham operated rats and those receiving electrical stimulation in the frontal cortex as a control. Operations were performed under sodium pentobarbital anesthetic, and NK activity against YAC-1 target cells was measured 20 h later using 51Cr release assay. The LH area stimulated is a potent reward center and that stimulation of this point increased NK activity opens the possibility that pleasure might play a role in cellular immunity.

Animals↗
PubMed1992

[Classical conditioning of anaphylaxis in sensitized guinea pigs].

An attempt of classical conditioning of anaphylaxis by odor was carried out, using actively sensitized guinea pigs with an inhalation of ovalbumin (OA). One month after sensitization, animals were divided into the conditioned group; group C, and the unconditioned group; group U, consisted of 6 animals, respectively. Dimethylsulfied (DMS: sulfur odor), was inhaled in group C as a conditioned stimulus with OA which is an unconditioned stimulus, while only OA was inhaled in group U. Four days after these procedures, saline was inhaled in group C and DMS was solely inhaled in group U in order to equalize the total inhaled dose of OA and DMS in both groups. These sessions were repeated once a week for seven weeks. After final sessions, all animals were inhaled DMS, saline and OA separately, and blood samples were drawn after each inhalation to measure plasma histamine levels. After an inhalation of DMS only, plasma histamine levels of group C and U were 47.5 +/- 9.7 and 25.7 +/- 1.2 ng/ml, respectively. In group C, plasma histamine levels were 32.9 +/- 4.7 at the inhalation of saline and 59.0 +/- 9.2 ng/ml at OA inhalation. Plasma histamine level after an inhalation of DMS only was significantly higher in group C than that in group U (p < 0.05). These results suggest that the conditional stimulus (DMS inhalation) may induce histamine release in the absence of any antigenic stimulus and support the evidence for mast cell-neuron interaction.

Anaphylaxis↗
PubMed1992

Effects of the biopsychosocial approach (BPSA) on exercise-induced asthma (EIA).

The Biopsychosocial Approach (BPSA) is a treatment program for allergic patients which includes therapy for psychological, behavioral and social factors as well as for physical problems, following basic principles of psychoneuroimmunology. BPSA was applied to patients with bronchial asthma and favorable results were obtained. The mechanism of the therapeutic effects of BPSA included normalization of the patient's autonomic nervous function, levels of blood histamine, and circadian rhythm of lymphocyte activity. BPSA was also used in patients with exercise induced asthma (EIA) and the same parameters were evaluated. Results showed that patients with EIA recovered physiological homeostasis after BPSA therapy normalized blood levels of histamine and substance P (SP), skin reactions to histamine and SP, and autonomic nervous function. We conclude that BPSA is effective for treating patients with EIA.

Adult↗
PubMed1991

Long-term follow-up investigation of the effects of the biopsychosocial approach (BPSA) to bronchial asthma.

The recent rapid increase in the number of allergic patients is becoming a social problem. Studies of the causes of this phenomenon involve various fields, with much attention focused on finding new antigens in food, air, articles encountered in daily living, etc. Recent studies of psychoneuroimmunology (PNI) also suggest a strong influence of emotions on allergic reactions. The number of allergic patients is increasing in all civilized countries without exception, and the stress prevalent in modern civilized society is related to this increase. Modern allergology does not yet have sufficient countermeasures for such stress states. We applied a biopsychosocial approach (BPSA) to treatment programs for allergic disease, incorporating treatment of physical and psychosocial problems en bloc. We studied the long-term effects of BPSA therapy on 82 patients who were treated for more than 3 months in the hospital and were examined 2 to 3 years after discharge. Results showed that more than 80% of patients maintained improvement and 45% of those with intractable asthma were able to withdraw from steroid hormones. BPSA achieved better results than those with standard medication administered only to the body. Improvements after treatment included physical changes, normalization of MV (microvibration) type, decreased levels of plasma histamine, and normal circadian rhythms of lymphocyte subsets. These changes reflect part of the physical mechanisms by which BPSA improves asthma symptoms. From a psychological view point, the patients' feelings, personal relations, behavior, etc. were changed after BPSA, allowing a new life style and improved QOL. It is important for asthma patients to maintain good overall condition over long periods. After BPSA, 80% of our patients were able to do so. It is difficult for the therapist to approach asthma from different aspects at once, including biological, psychological, and social, so we developed a five-stage program of BPSA therapy and found that this obtained favorable results.

Adult↗
PubMed1990

The central inhibitory effect of interleukin-1 on gastric acid secretion.

The effect of interleukin-1 (IL-1) on gastric secretory functions was examined in pylorus-ligated conscious rats. Intracisternal (i.c.) injection of IL-1 beta (1-100 ng) induced dose-related, long-lasting inhibition of gastric acid output, which was due to the reductions of both the amount and the acid concentration of the gastric juice. A much higher dose of IL-1 alpha was required to achieve identical effects on gastric acid secretion when it was given by intravenous routes. The i.c. injection of IL-1 alpha also had an inhibition of gastric secretion. This inhibitory effect of i.c. applied IL-1 beta on gastric acid secretion was completely abolished in indomethacin-pretreated animals but not in reserpine-pretreated ones. These results suggest that IL-1 may have an inhibitory action on the regulation of gastric secretory functions by its central action which is dependent on the eicosanoid metabolism.

Animals↗