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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of i.v. infusions of althesin, ketamine and thiopentone were studied in instrumental rabbits, in doses that produced similar levels of light anesthesia. The main hemodynamic differences were in the rises in mean arterial pressure (MAP) and in total peripheral resistance (TPR) which were in the order of ketamine greater than thiopentone greater than althesin. These rises in MAP and TPR did not occur in sino-aortic denervated rabbits suggesting that in normal rabbits these depended on the integrity of the arterial baroreceptors and /or chemoreceptors. The heart rate increased with all anesthetics mainly owing to reduction in vagal efferent activity, except with althesin where cardiac sympathetic activity increased also. Baroreceptor--heart rate reflex properties were studied by deriving sigmoid curves relating MAP to heart period (HP, i.e. pulse interval). All drugs depressed the following curve parameters: (i) HP range, i.e. the difference in HP plateaux from maximal tachycardia to maximal bradycardia; and (ii) the reflex gain (sensitivity). The order of depression was ketamine greater than thiopentone greater than althesin, i.e. the same as the order in which they evoked pressor effects. The results suggest that the 3 anesthetics produce differing depression of afferent mechanisms related to baroreceptor reflexes and that this accounts for both the differences in pressor effects (through disinhibition of constrictor tone) and in depression of the vagal and sympathetic components of the baroreceptor--heart rate reflex.
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PMID:Role of baroreceptor reflexes in the hemodynamic and heart rate responses to althesin, ketamine and thiopentone anesthesia. 726 95

The effects of active and inactive enkephalin derivatives and naloxone on putative interneurons were studied in the in vitro hippocampal slice. Inhibitory interneurons were recorded from extracellularly, and identified electrophysiologically on the basis of their characteristic action potential shape and pattern of evoked firing in response to single and multiple electrical stimuli. Active enkephalin derivatives elicited a dose-dependent depression in excitability whereas inactive derivatives had no effect. Naloxone reliably and reproducibly antagonized the depressant action of active enkephalins. These data confirm the hypothesis outlined in the preceding communication, that the direct effect of enkephalins in the hippocampus is a depression of firing of inhibitory neurons, and support the hypothesis that enkephalin-induced excitations of pyramidal cells are brought about by disinhibition.
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PMID:Electrophysiological interactions of enkephalins with neuronal circuitry in the rat hippocampus. II. Effects on interneuron excitability. 735 59

The effects of ketamine 5 mg/kg on blood pressure, heart-rate and the efferent action-potentials of the sympathetic and phrenic nerves were investigated in 17 relaxed and artificially ventilated cats. In part of the experiments (8 cats) ketamine was given as the sole narcotic agent, in the rest ketamine was applied a light basic as anaesthesia with N2O/O2 in relation of 2:1. The findings were, that ketamine given as monoanaesthetic agent increase blood pressure and heart-rate, as well as efferent sympathetic activity. The registration of the phrenic nerve activity showed a prolongation of the inspiratory periods, but no change of the general activity. In contrast, ketamine combined with nitrous-oxide resulted in a reduction of blood pressure and in a clear depression of the activity of both the sympathetic and phrenic nerves. These results may lead to the conclusion, that the blood pressure increasing effect of ketamine is, at least to a large extent, due to a suppression of inhibitory neurons in central-nervous sympathetic areas, whereas the increase of the heart-rate may be caused by a depression of parasympathetic centres. The characteristic changes of the inspiratory activity of the respiration centre may be due to a disinhibition of inspiratory neurons. Because these results were obtained after application of anaesthetically effective doses, these experiments lead to the conclusion, that after application of ketamine, effects were registered in the stage of tolerance, which with other anaesthetics only appear in the stage of excitation.
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PMID:[Investigations on the mechanism of the effects of ketamine (Ketanest) on circulation and respiration (author's transl)]. 744 46

Fifty-three self-defined compulsive eaters recruited from weight loss programs and a college population and prescreened to eliminate probable anorexics and bulimics participated in this study. They completed the Three Factor Eating Questionnaire, Beck Depression Inventory, Compulsive Eating Scale, Eating Obsessive-Compulsive Questionnaire, Personal Assertion Analysis, and provided demographic information. Participants had high scores for compulsive eating and disinhibition and low scores for depression. The best predictors of compulsive eating were disinhibition and obsessive thoughts of food, which accounted for 61% of the variance. Twenty-one percent of the sample reported a history of sexual abuse. Thirty-one percent of the sample were classified as medically obese, yet 49% perceived themselves to be moderately to very overweight.
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PMID:Compulsive eating, obsessive thoughts of food, and their relation to assertiveness and depression in women. 759 68

Women commonly report increased cravings for foods high in sugar, fat, and/or salt premenstrually relative to other times during the menstrual cycle. To determine if elevated cravings for foods high in salt and/or fat were related to alterations in food preferences across the menstrual cycle, preference and sensory ratings for air-popped popcorn with varying levels of salt (0.0, 1.5, and 4.0 g) and butter (3.3, 10, and 30 g) added to 30 g of popcorn were assessed in 34 normal-weight, college-aged women for 4 consecutive weeks. Additionally, using the Profile of Mood Scale (POMS), mood states were determined across the menstrual cycle. Dietary restraint, disinhibition, and hunger were assessed using the Three Factor Eating Questionnaire (TFEQ). Neither preference ratings nor ratings of the saltiness or fatness of the popcorn samples varied as a function of the menstrual cycle. Moreover, no differences in mood states were observed across the menstrual cycle. However, preference ratings for the popcorn samples were significantly greater for restrained than unrestrained eaters. Restrained eaters also rated the samples as significantly more salty, and had significantly higher scores on the tension-anxiety and depression-dejection subscale of the POMS than unrestrained eaters. Additionally, preference ratings of women who reported exercising more than 3 h a week were significantly greater than those of women who reported exercising less than 3 h a week. It is hypothesized that the variations in preference ratings observed as a function of dietary restraint and exercise are the result of differences in cognitive beliefs about food, rather than differences in physiological factors.
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PMID:Preferences for foods with varying levels of salt and fat differ as a function of dietary restraint and exercise but not menstrual cycle. 761 Jan 29

The present study aimed at investigating the question whether abnormalities of sleep, especially disinhibition of rapid eye movement (REM) sleep, are already present in adolescents with primary major depressive disorder (MDD). Ten healthy controls assessed at home, 10 inpatients with MDD and 10 inpatients with schizophrenia (age range: 13-19 years) were investigated polysomnographically. REM latency was significantly shortened in MDD compared with the two other groups. Adolescents with MDD did not display disturbances of sleep continuity as typically observed in adults with major depression. The most pronounced impairment of sleep continuity was noted in schizophrenic patients. The results stress that shortened REM latency may already occur in adolescent depression.
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PMID:Sleep in adolescents with primary major depression and schizophrenia: a pilot study. 775 93

Recently it was hypothesized that the antidepressant response to total sleep deprivation (SD) results from a disinhibition process induced by the increase of tiredness in the course of SD. In the present study, the role of tiredness in the antidepressant response to SD is further investigated. Seventy-two depressed patients scored subjective tiredness and depressed mood three times daily (in the morning, afternoon, and evening) on the days preceding and following SD. It was found that averaged tiredness on the day prior to SD was related to the SD response, when the severity of depression prior to SD had been held statistically constant. Also, when both severity of depression and diurnal variation of mood prior to SD were partialed out, tiredness showed a positive correlation with the SD response: patients who reported a relatively low degree of tiredness on the day preceding SD improved by SD. This result suggests that tiredness has an influence on SD effects, and that this influence is independent from that of the severity of depression. The findings are in accordance with current ideas on the role of tiredness as a mediating factor in the induction of the therapeutic effects of SD.
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PMID:The relationship between tiredness prior to sleep deprivation and the antidepressant response to sleep deprivation in depression. 778 59

Abnormalities of REM sleep, i.e. shortening of REM latency, lengthening of the duration of the first REM period and heightening of REM density, which are frequently observed in patients with a Major Depressive Disorder (MDD), have attracted considerable interest. Initial hopes that these aberrant patterns of sleep constitute specific markers for the primary/endogenous subtype of depression have not been fulfilled. The specificity of REM sleep disinhibition for depression in comparison to other psychopathological groups is also challenged. Demographic variables like age and sex exert strong influences on sleep physiology and must be controlled when searching for specific markers of depressed sleep. It is still an open question whether abnormalities of sleep are state-markers or trait-markers of depression. Beyond baseline studies, the cholinergic REM induction test (CRIT) indicated a heightened responsitivity of the REM sleep system to cholinergic challenge in depression compared with healthy controls and other psychopathological groups, with the exception of schizophrenia. A special role for REM sleep in depression is supported by the well known REM sleep suppressing effect of most antidepressants. The antidepressant effect of selective REM deprivation by awakenings stresses the importance of mechanisms involved in REM sleep regulation for the understanding of the pathophysiology of depressive disorders. The positive effect of total sleep deprivation on depressive mood which can be reversed by daytime naps, furthermore emphasizes relationships between sleep and depression. Experimental evidence as described above instigated several theories like the REM deprivation hypothesis, the 2-process model and the reciprocal interaction model of nonREM-REM sleep regulation to explain the deviant sleep pattern of depression. The different models will be discussed with reference to empirical data gathered in the field.
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PMID:[Depression and sleep--the status of current research]. 783 18

Five parallel anatomic circuits link regions of the frontal cortex to the striatum, globus pallidus/substantia nigra, and thalamus. The circuits originate in the supplementary motor area, frontal eye fields, dorsolateral prefrontal region, lateral orbito-frontal area, and anterior cingulate cortex. Open loop structures that provide input to or receive output from specific circuits share functions, cytoarchitectural features, and phylogenetic histories with the relevant circuits. The circuits mediate motor and oculomotor function as well as executive functions, socially responsive behavior, and motivation. Neuropsychiatric disorders of frontal-subcortical circuits include impaired executive function, disinhibition, and apathy; indicative mood disorders include depression, mania, and lability. Transmitters, modulators, receptor subtypes, and second messengers within the circuits provide a chemoarchitecture that can inform pharmacotherapy.
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PMID:Frontal-subcortical circuits and neuropsychiatric disorders. 750 69

During the 12-year period of retrospective observation, 38 cases of 93 major depressive inpatients were delusional and the remainders were nondelusional. We evaluated the differences on several variables, especially about suicide, between the two groups. The mean age at the onset of illness of delusional depressive patients was higher than that of nondelusional ones. The incidence of psychomotor retardation was lower in the former group than in the latter. The frequency of suicidal ideation and suicidal attempts were higher in the former group than the latter. The suicidal methods in the delusional depressives tended to be more active and violent than those in nondelusional depressives and were supposed to have a twofold mortality than those in the nondelusional ones. We discussed this high rate of suicides of delusional depression from the viewpoint of disinhibition of psychomotor retardation, chronicity, partial affinity of delusional depressives to schizophrenics and neuroendocrinological perspective.
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PMID:Delusional depression and suicide. 791 Nov 66


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