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)

Carbromal is metabolized extensively in humans. The major metabolites known to date are bromoethylbutyramide, ethylbutyrylurea and inorganic bromide. After ingestion of a therapeutic dose of 1.0 g carbromal (4.2 mmoles) by four healthy volunteers highest concentrations in serum were found to be for carbromal 30 mumoles/l, for bromoethylbutyramide up to 20 mumoles/l and for ethylbutyrylurea 2--3 mumoles/l. In patients acutely poisoned by carbromal-containing sedatives serum concentrations measured were in the range of 200 mumoles/l carbromal, 350 mumoles/l bromoethylbutyramide and 50 mumoles/l ethylbutyrylurea. These patients were comatose, apneic, had isoelectric encephalographic records and decreased body temperature. The degree of central nervous depression as judged by clinical signs was found to correlate with the serum concentrations of carbromal and of bromoethylbutyramide. Pharmacological activity and acute toxicity of carbromal and its two metabolites were examined in rats and compared with the activity of phenobarbitone. For intraperitoneal injection LD-50 values were found to be for carbromal 1.8 mmoles/kg, for bromoethylbutyramide 1.5 mmoles/kg, for ethylbutyrylurea 5.0 mmoles/kg and for phenobarbitone 0.9 mmoles/kg. Carbromal and bromoethylbutyramide severely decreased body temperature. The relative narcotic activity was estimated to be for carbromal = 100; bromoethylbutyramide = 66; ethylbutyrylurea = 33; phenobarbitone = 100. The anticonvulsive activity against pentetrazol-induced generalized seizures was nearly identical for carbromal, bromoethylbutyramide and phenobarbitone. Anticonvulsant activity of ethylbutyrylurea was two to three times less than that of carbromal. Inorganic bromide was found to increase the narcotic activity of carbromal and of bromoethylbutyramide. The findings show that the clinical signs of central nervous system depression seen in patients acutely poisoned with carbromal are caused mainly by unchanged carbromal and by its metabolite bromoethylbutyramide.
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PMID:[On the toxicology of carbromal. III. Role of active metabolites in humans acutely poisoned with carbromal-containing sedatives (author's transl)]. 2 10

The steady rise in the promiscuous use of phencyclidine (PCP) as a "recreational" drug has recently gained nationwide attention because of the numerous violent and/or bizarre incidents caused by the use of this drug. Because the media often exaggerate reports of bizarre and violent behavior to make a "good" story, the potential PCP user may be tempted to ignore the media warnings. In the case of PCP, however exaggerated the story, a real danger does exist. So, despite numerous newspaper, radio and television warnings about the possible consequences of PCP use and abuse, the incidence of toxic reactions continues to climb. In many cases PCP is sold as other drugs, particularly THC, and in various colored capsules, tablets, liquids and crystals which may explain the increased usage despite the numerous warnings against its use. The advances in laboratory techniques and chemical processess have enabled the clandestine chemist to prepare relatively pure PCP and thus eliminate many of the toxic side effects due to impurities in the drug. In addition, 30 or more psychoactive PCP analogues have been developed and are starting to make an appearance on the street. PCP is perhaps the most potent psychotomimetic compound known at the present time and is capable of inducing a psychosis which is clinically indistinguishable from schizophrenia. The psychosis-producing effects of PCP are the most common toxic effects seen in hospital emergency rooms; but as the amount of PCP taken and/or the simultaneous involvement of other drugs, particularly barbiturates, occurs, severe medical problems (e.g., coma, seizures, respiratory arrest) begin to appear. Death from high doses of PCP or PCP plus other drugs does occur, but the principal cause of death from PCP abuse is due to trauma, homicide or suicide (usually of the bizarre or violent form). Young adult males, persons predisposed to mental illness and naive drug users appear to be the most susceptible to the adverse effects of PCP. The fact that chronic PCP users are starting to increase in number is mute testimony that not all users experience "bad trips" with PCP. Unfortunately for the user, however, this does not guarantee that the next trip will not be a bad one. The effects of chronic use seem to be twofold: severe depression with suicidal thoughts and numerous violent, agitated behavioral patterns. Neither seems to be a suitable alternative. At the present time there is not specific antidote for toxic PCP reactions and the prolonged psychosis induced in some cases does not appear to respond to the standard antipsychotic medications as quickly as do the functional psychoses. The major improvement from a medical standpoint is the development of more sensitive laboratory techniques to confirm the presence of PCP in body fluids. This advance has undoubtedly led to the apparent increase in the number of PCP cases reported by hospitals and to the accuracy of clinical diagnosis by medical, drug or law enforcement communities...
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PMID:PCP (phencyclidine): an update. 4 8

The unilateral and bilateral therapy differ in psycho-organic effects but have the same antidepressive efficiency. This is due to the facts that the organic effects are mainly caused by the electrical current whereas the antidepressive effect is dependent on the seizure activity. Compared to the bilateral treatment, unilateral gives reduced confusion, anterograde and retrograde amnesia as well as reduced experience of memory impairment. The difference is explained by a lower density of current in the brain. The unilateral treatment should be the treatment to be chosen. The antidepressive action of ECT fits the amine hypothesis, ECT causes a sustained increase of the synthesis of norepinephrine and of the sensitivity of amine receptors and creates conditions for alleviating both "low-output" and "low-sensitivity" depression. The antidepressive action is probably mediated by release of hypothalamic neurohormones.
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PMID:[Unilateral and bilateral shock therapy: mechanism of action (author's transl)]. 4 67

70 chronic alcoholics in the withdrawal state, 45 with convulsions and 25 controls without convulsive seizures, were tested with respect to electrolyte changes and acid base balance in serum or blood and cerebrospinal fluid (CSF). It was of special interest to note that there was a partial independence between magnesium levels in serum and CSF. Thus the serum level has only a limited liability as to magnesium depletion suggested to be responsible for seizure precipitation. In the seizure group a slightly but significantly lower magnesium, potassium and calcium in CSF and a significant decrease of potassium and calcium in serum were revealed. In the nonzeizure controls a similar decrease of magnesium in serum and potassium in CSF was observed while serum potassium and calcium in CSF and serum remained in low normal range. In both groups there was a prominent respiratory alkalosis. The role of magnesium depression for seizure precipitation is discussed with respect to the concomitant changes of other electrolytes and acid base disturbances.
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PMID:Electrolyte changes and acid base balance after alcohol withdrawal, with special reference to rum fits and magnesium depletion. 6 5

The effect of manipulation of GABA mechanisms in the region of the nucleus accumbens on dopamine-dependent locomotor hyperactivity in the rat has been studied. Two models of hyperactivity were used: (1) the injection of dopamine into the region of the nucleus accumbens in nialamide-pretreated animals and (2) the systemic administration of d-amphetamine. Both GABA and the GABA agonist 3-aminopropane sulphonic acid (3-APS) depressed hyperactivity in a dose-related manner. High concentrations of GABA (greater than 100 micrograms) were required to produce a significant effect and the response was short-lived possibly reflecting the efficient GABA inactivating mechanisms. 3-APS proved to be approximately 10 times more potent as compared to GABA in the dopamine-accumbens hyperactivity model. Conversely GABA receptor antagonism with low doses of either picrotoxin or bicuculline enhanced the mild locomotor response induced by a low dose of dopamine injected into the nucleus accumbens. However such results were difficult to evaluate fairly as higher doses of the GABA antagonists resulted in varying degrees of generalized seizures. Blockade of GABA uptake systems with cis-1, 3-aminocyclohexane carboxylic acid (ACHC), nipecotic acid or beta-alanine within the region of the nucleus accumbens produced dose-related depression of dopamine-dependent hyperactivity in both models. GABA uptake blockade (nipecotic acid) significantly enhanced the GABA-mediated depression of hyperactivity induced by bilateral injection of dopamine into the nucleus accumbens. The results demonstrate an inhibitory action of GABA and drugs facilitating GABA-ergic transmission on dopamine-dependent hyperactivity in the rat. Although open to criticisms of not being able to distinguish between true GABA effects and the results of non-specific neuronal depression the hyperactivity model underlines the potency of the GABA uptake blocking compounds and their possible potential for future clinical use.
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PMID:Dopamine-dependent hyperactivity in the rat following manipulation of GABA mechanisms in the region of the nucleus accumbens. 11 17

The mechanisms of the anticonvulsant activity of cannabidiol (CBD) and the central excitation of delta 9-tetrahydrocannabinol (delta 9-THC) were investigated electrophysiologically with conscious, unrestrained cobalt epileptic rats. The well-known antiepileptics, trimethadione (TMO), ethosuximide (ESM), and phenytoin (PHT), were included as reference drugs. Direct measurements were made of spontaneously firing, epileptic potentials from a primary focus on the parietal cortex and convulsions were monitored visually. ESM and TMO decreased the frequency of focal potentials, but PHT and CBD exerted no such effect. Although CBD did not suppress the focal abnormality, it did abolish jaw and limb clonus; in contrast, delta 9-THC markedly increased the frequency of focal potentials, evoked generalized bursts of polyspikes, and produced frank convlusions. 11-OH-delta 9-THC, the major metabolite of delta 9-THC, displayed only one of the excitatory properties of the parent compound: production of bursts of polyspikes. In contrast to delta 9-THC and its 11-OH metabolite, CBD, even in very high doses, did not induce any excitatory effects or convulsions. The present study provides the first evidence that CBD exerts anticonvulsant activity against the motor manifestations of a focal epilepsy, and that the mechanism of the effect may involve a depression of seizure generation or spread in the CNS.
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PMID:The influence of cannabidiol and delta 9-tetrahydrocannabinol on cobalt epilepsy in rats. 11 6

We measured simultaneously the oxidative metabolic activity, monitored as the tissue fluorescence attribute to intramitochondrial NADH, the extracellular potassium level with ion-selective microelectrodes, and the focal extracellular electrical potential, of one site in intact cerebral cortex of cats. When the cerebral was stimulated by trains of repeated electric pulses applied either directly to its surface or to an afferent pathway, the corrected cortical fluorescence (F-R) declined indicating oxidation of NADH, the activity of extracellular potassium [K+]o increased, and the extracellular potential (Vec) shifted in the negative direction. When mild to moderate stimuli not exceeding 10-15 sec in duration were used, a 3-fold correlation was found between these three variables. The regression of F-R over either Vec, or over log [K+]o had a positive ordinal intercept. The results are in agreement with earlier suggestions 4,24,25,43,45,46 that (a) much but not all the oxidative metabolic response of cortex to electrical stimulation is expended in restoring disturbed ion balance; and (b) that sustained shifts of potential (SP) in response to repetitive electrical stimulation are generated by glia cells depolarized by excess potassium. The magnitude of SP shifts associated with a given elevation of [k+]o are smaller in cerebral cortex than in spinal cord48,49. The correlation of F-R with [K+]o breaks down when pathologic processes of either seizure activity or spreading depression set in. During paroxysmal activity [K+]o tends to remain confined below 10-12 mM, a level observed in non-convulsing cortex as well, but oxidation of NADH progresses beyond that seen in non-convulsing cortex as well, but oxidation of NADH progresses beyond that seen in non-convulsing tissue. This observation is hard to reconcile with the suggestion that excess potassium is a factor in the generation of seizures, at least of the type observed in this study. When [K+]o levels exceeded 10-12 mM, spreading depression invariably followed at least under the unanesthetized condition in these experiments. During spreading depression [K+]o levels rose to exceed 30 mM, sometimes 80 mM. NADH was oxidized during spreading depression to a level comparable to that seen in seizures. The observations are compatible with the suggestion13 that spreading depression occurs whenever the release of potassium into extracellular fluid is overloading its clearance therefrom.
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PMID:Responses of electrical potential, potassium levels, and oxidative metabolic activity of the cerebral neocortex of cats. 16 65

Reviewed is the author's investigation of potassium in extracellular fluid of cerebral neocortex and spinal cord determined with ion-selective microelectrodes, and of oxidative metabolism monitored by fluorometric determination of intramitochondrial NADH in intact cortex. When gray matter is excited by afferent input, or by direct electrical stimulation, the logarithm of the rise of extracellular potassium concentration ([K+]0), the sustained shift of electrical potential, and the response of oxidative metabolism are linearly correlated. However, during seizures and during spreading depression, the correlation is broken, suggesting that the demand for oxidative energy exceeds that corresponding to the elevation of [K+]0. There exists a critical concentration of [K+]0 at which spreading depression inevitably erupts (12 mM for cat cerveau isole), but no such critical level could be detected for seizures. The rate of clearance of excess potassium from extracellular fluid is slower for high concentrations than for low; this rate is further slowed by the administration of phenobarbital, and possibly also of diphenylhydantoin. Changes of membrane potential of glia cells in the mammalian spinal cord can adequately be described by the Nernst equation.
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PMID:Potassium, neuroglia, and oxidative metabolism in central gray matter. 17 18

Five patients received overdoses of vincristine ranging from 3.5 to 32 mg. Neurotoxicity accounted for most of the complications observed. Peripheral neuropathies, cranial nerve palsies, paralytic ileus, atony of the bladder, hypertension, hypotension, seizures, inappropriate ADH secretion, and severe bone marrow depression were all encountered. Two patients died within 72 hours of the overdose. Another patient died of sepsis 22 days after the overdose. Two patients recovered and were discharged. The three patients who survived longer than a few days showed improvement in the vincristine-induced neuropathy, and the two long-term survivors had essentially complete recovery. It appears that if a patient can be supported through the critical period following an overdose, he can be expected to recover normal neurologic function.
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PMID:Overdosage with vincristine. 18 48

A subclinical EEG seizure occurred in each of 2 patients during a test that repeatedly evoked probable mild cerebral hypoxia. The firing rate of the neurons was unaffected until the EEG seizure had been ongoing for over a minute. After the EEG seizures, all neurons were profoundly depressed regardless of whether their responses to hypoxia had been an increase, decrease, or no change in firing rate. These observations indicate that the mechanism responsible for post-EEG seizure depression of neuronal firing is probably not cerebral hypoxia.
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PMID:Post-EEG seizure depression of human limbic neurons is not determined by their response to probable hypoxia. 19 45


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