Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chorontropic response of isolated rabbit atria in normal Tyrode's medium increases monotonically with increasing doses of histamine (9 X 10-7 -9 X 10-4 M). Plots of the inverse of response against the inverse of concentration were linear; and from these plots were derived values fro the theoretical maximum response at 'infinite' dose and for pH histamine concentration required to evoke a half maximum response. Alteration of pH by changing (HCO3-) at a constant pCO2, (Na) and osolality did not appreciably affect the response to histamine in the range pH 7.0-7.6. However, at pH below 7.0 the magnitude of histamine response was reduced at all concentrations of histamine tested. In the pH range 7.0-7.6, additions of NaHCO3 at constant pCO2 increased the spontaneous rate of rabbit atria (in the absence of histamine); however, there was little effect of changing pH (in this range) by altering (HCO3-) at constant pCO2 when (Na+) and osmolaity were kept constant. Immersion in solutions at pH's less than 7.0 led to decline in spontaneous rate and force contraction. It is probable that depression of adenyl cyclase activity rather than a specific change in ionization of histamine receptor is responsible for a decreased response to histamine at pH 6.9.
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PMID:The effect of pH on rabbit atrial response to histamine. 0 37

Platelets were examined to enable a simultaneous investigation to be made of indolylamine and electrolyte metabolism in affective disorder. No significant differences were detected in either platelet membrane ATPase or adenyl cyclase specific activity in any of the groups of patients studied, when compared with appropriate controls. A reduced Vmax and y for the 5-hydroxy-tryptamine uptake process into platelets was observed in both unipolar and bipolar depressed groups. The Km for this process was not significantly different in any of the patients from that found in control subjects. Lithium therapy was shown not to influence significantly any of the platelet parameters examined. It is suggested that membrane enzyme changes found in some peripheral cells in patients suffering from affective disorder, i.e. reduced Na+ + K+ - ATPase activity in erythrocytes in depression, is not common to all peripheral cells and may or may not reflect central nervous system changes.
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PMID:Studies on human blood platelets in affective disorder. 15 82

The effect of hypoxia on glycogen content, adenyl cyclase activity, cyclic 3',5'-AMP concentration, lactate: pyruvate ratio and the energy charge potential connected with the pool of adenylates was evaluated in the motor area of the cortex of beagle dogs. At first, controlled hypoxia induces activation of the adenyl cyclase system while subsequently, with PaO2 values lower than 20 mm Hg, a depression of the system is observed simultaneously with a drop of the energy charge potential. When normal oxygenation is resumed, the biochemical parameters examined tend to go back to normal even though it is still necessary to resort to anaerobic mechanisms. The intracarotid perfusion with nicergoline enhances the post-hypoxic recovery of adenyl cyclase activity, even though the ergoline derivative is inactive during the stages of hypoxic suffering of the brain studied in the present work.
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PMID:Effect of hypoxia on the cerebral energy state. 16 98

Insulin accelerates the entry of glucose and amino acids into muscle cells by acting upon the 'carrier-facilitated' transport mechanism. For glucose this process is passive and leads to equilibration of intracellular and extracellular concentrations. In heart muscle, glucose transport is a rate-limiting step for glucose uptake. During hypoxia and ischemia the heart turns to anaerobic glycolysis for energy production and therefore, maximal glucose transport becomes important. Insulin is necessary to insure proper protein synthesis, probably at the level of membrane-bound polyribosomes. However, during myocardial hypoxia, insulin alone cannot restore the associated depression in protein synthesis. Although insulin hyperpolarizes the cell, a change in the ratio of intracellular to extracellular activities of potassium is not its primary mode of action. An insulin-induced configurational change in the plasma membrane could simultaneously account for the effects of insulin on sodium and potassium permeability and the action on facilitated transport. Intracellular levels of cyclic adenylate may be reduced by insulin in adipose tissue because of inhibition of adenyl cyclase or stimulation of phosphodiesterase. However, at this time there is little evidence that insulin alters cyclic AMP levels in the heart. Insulin secretion is depressed in patients with heart disease in proportion to the reduction of cardiac index sustained. Since the ischemic heart is dependent upon glucose as the major fuel, insulin lack may deprive the heart of adequate substrate.
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PMID:Insulin: fundamental mechanism of action and the heart. 18 67

1. The effects of phenol and phenyl glucuronide on the responses of normal rat brain adenyl cyclase to noradrenaline and dopamine have been investigated. Neurotransmitter responses have also been examined in brains from uraemic and normal rats. 2. A depressive effect of phenol on the adenosine 3' :5' -cyclic monophosphate response of the neostriatum to dopamine was shown to be completely abolished if the toxin was present in the conjugated form; the response of the cortex to noradrenaline was stimulated by the presence of phenyl glucuronide, even though the unconjugated form had no effect. 3. The uraemic state in the rat also resulted in a depression of the neostriatum response to dopamine, yet an enhancement of the cortical response to noradrenaline. 4. The action of phenols of the brain is relevant to hepatic and uraemic coma.
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PMID:Effect of unconjugated and conjugated phenol and uraemia on the synthesis of adenosine 3' :5' -cyclic monophosphate in rat brain homogenates. 21 46

Cholera toxin may depress cell-mediated immunity by stimulation of adenyl cyclase and production of cyclic AMP in cellular systems or when given parenterally to experimental animals. Whether or not similar effects might be found during clinical infection with Vibrio cholerae was the subject of this study. Delayed hypersensitivity reactions to skin test antigens were found to be markedly depressed in Bengali patients with cholera 24 h after fluid repletion. Skin test response rates were lower in children and in adults with the disease than in both normal adults and children or in adults with an equivalent degree of malnutrition. Patients with equal degrees of dehydration due to noncholera diarrhea were significantly less immunosuppressed. Concurrent depression of other manifestations of cell-mediated immunity was not found.
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PMID:Depression of cell-mediated immunity in cholera. 42 32

Preclinical neurochemical studies indicate that buspirone and gepirone bind selectively to presynaptic (dorsal raphe) and postsynaptic (hippocampus, cortex) 5-hydroxytryptamine1A (5-HT1A) receptor binding sites. Furthermore, in functional neurochemical and electrophysiologic receptor studies, azapirones in general display partial agonist activity at postsynaptic 5-HT1A receptors linked negatively to adenyl cyclase and appear to demonstrate a similar profile on hippocampal CA1 pyramidal neurons sensitive to the effects of 5-HT. Through their action at presynaptic 5-HT1A receptors, these agents have been shown to dose-dependently inhibit cortical and hippocampal 5-HT synthesis while inhibiting the firing of 5-HT--containing dorsal raphe neurons, both in vitro and in vivo. These results suggest that the efficacy seen in clinical trials of anxiety and depression may be related to buspirone's and gepirone's complex interaction with presynaptic and postsynaptic 5-HT1A receptors, which initiate long-term changes in central 5-HT neurotransmission.
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PMID:Neurochemistry and neurophysiology of buspirone and gepirone: interactions at presynaptic and postsynaptic 5-HT1A receptors. 197 41

The metabolism of adenosine 3',5'-monophosphate (cyclic AMP) was studied in specific pathogen-free mice exposed to neonatal infection with mouse enterovirus or to malnutrition during early life. Metabolic activity was determined by measuring the turnover of cyclic AMP-8-(14)C to respiratory (14)CO(2), its incorporation into various organs and plasma, and the binding activity of synaptosome for cyclic AMP. Early malnutrition increased the catabolism of cyclic AMP as measured by expiration in respiratory CO(2). The level of cyclic AMP was lower in plasma and its incorporation into various tissues was decreased in infected and malnourished animals. Metabolic products of cyclic AMP were isolated from plasma by ion exchange chromatography. Cyclic AMP-8-(14)C had completely disappeared 9 hr after injection. Fewer metabolites of cyclic AMP were detected in infected or malnourished groups than in controls and the metabolic reaction from 5'-AMP to adenosine seemed to be slow in these animals. The ability to incorporate cyclic AMP to synaptosome was also impaired in the experimental groups. The concentrations of brain cyclic AMP were lower in infected or malnourished animals than in controls. Depression of accumulation of cyclic AMP probably resulted from excessive activity of phosphodiesterase, rather than from impairment of adenyl cyclase. Intraperitoneal administration of theophylline brought the activity level of phosphodiesterase to normal in infected or malnourished mice; this fact probably accounted for enhanced accumulation of brain cyclic AMP.
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PMID:Lasting biological effects of early environmental influences. VII. Metabolism of adenosine in mice exposed to early environmental stress. 433 97

Parathyroid hormone (PTH) and calcitonin exert well known effects on the renal tubule which are thought to involve specific hormone receptors and adenyl cyclase. In the intestine, it is not clear whether the action of PTH and calcitonin is only indirect or also direct, and their mechanisms of action are much less well established. In the present study, possible direct effects of PTH and calcitonin on Na+ transport in isolated intestinal epithelial cells of rats were investigated. In the presence of bovine PTH (1.2 I.U/ml) in the incubation medium, the Na+ efflux rate constant (oKNa) of isolated enterocytes was significantly reduced when compared to that in control experiments with the hormone vehicle only. The mean depression of oKNa induced by bovine PTH was 26% as compared to the control (100%) and to that induced by ouabain (4.0 mM) which was 44%. No depressant effect of bovine PTH on oKNa was observed when the isolated enterocytes were incubated with ouabain (4.0 mM). Thus, bovine PTH appeared to inhibit the ouabain-sensitive Na+ pump. When incubating the isolated epithelial cells in an EGTA-containing CA2+-free medium, bovine PTH lost its capacity to inhibit oKNa. Thus, the presence of extracellular Ca2+ appeared necessary for the inhibitory effect of bovine PTH. In contrast to its effect on oKNa, bovine PTH induced no change in net Na+ uptake by isolated enterocytes. Moreover, no significant effect on enterocyte Na+ transport could be demonstrated for salmon or porcine calcitonin at two different concentrations in the incubation medium, Neither bovine PTH nor salmon calcitonin induced significant changes in enterocyte cyclic AMP or cycle GMP concentrations. It was concluded that bovine PTH, but not calcitonin, exerted a directed inhibitory effect on the ouabain-sensitive oKNa of isolated rat enterocytes. The effect of bovine PTH occurred without measurable activation of the cyclic nucleotide system but needed the presence of Ca2+ in the incubation medium to be operative.
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PMID:Rat enterocyte Na+ transport in vitro. Action of parathyroid hormone and calcitonin. 627 49

A series of six experiments was conducted to investigate the effects of Mg deficiency in the young rat on parathyroid hormone (PTH) activity and on response to parathyroid extract (PTE) and to endogenously produced PTH stimulated by dietary Ca deficiency. Major criteria employed were 45Ca release from pre-labeled bone and urinary excretion of cAMP. Mg deficiency was accompanied by lowered 45Ca mobilization and urinary cAMP excretion, indicating either a depression in PTH secretion or tissue insensitivity to it. Administration of PTE resulted in equivalent increases in 45Ca mobilization irrespective of Mg status but increased cAMP excretion only in Mg-adequate animals, thus indicating a depressed sensitivity of kidney to PTH in the Mg-deficient animal. In vitro response of kidney cortex from Mg-deficient animals to PTE added to incubation medium indicated no defect in the adenyl cyclase system. Endogenous stimulation of PTH by low Ca diet increased cAMP in Mg-adequate animals but not in rats with pre-existing Mg deficiency. Mg deficiency did not reduce cAMP previously stimulated by Ca deficiency.
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PMID:Effect of magnesium deficiency on rat bone and kidney sensitivity to parathyroid hormone. 740 Aug 50


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