Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rats were kindled during exposure to caffeine (50 mg/kg) or saline given IP twenty minutes before daily electrical stimulation of the amygdala until 3 kindled amygdaloid seizures (KAS) occurred. They were then stimulated for 3 days without drug pretreatment followed by 5 additional days with drug pretreatment. There were no significant differences between the two groups in the number of daily stimulations or in the total seconds of cumulative afterdischarge (AD) needed to reach the first KAS. During kindling, the daily average AD tended to be longer in the caffeine treated group. This difference became significant (greater than 200% saline) when the KAS was reached. When KAS animals were stimulated without caffeine pretreatment, the average AD returned to control lengths. When put back on caffeine pretreatment, the average AD was again increased. Caffeine (6-50 mg/kg, IP) was also evaluated in previously kindled rats using suprathreshold (400 mu AMP) and threshold (20 microA increments) seizures. Caffeine had no consistent effect on threshold values. However, 12-50 mg/kg of caffeine increased seizure severity and AD durations after threshold stimulation. With suprathreshold stimulation, the length of the AD was significantly increased only after the highest dose of caffeine. It would appear that caffeine lengthens induced afterdischarges both during the acquisition phase of kindling and in the fully kindled subject. Caffeine does not appear to lower seizure thresholds or increase the rate of acquisition of the KAS in the doses tested in this model.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Caffeine modification of kindled amygdaloid seizures. 663 84

We analyzed brain tissue in 139 rats for adenosine and its metabolites, inosine and hypoxanthine, during the initial 120 seconds of seizures induced by bicuculline. We also measured ATP, ADP, AMP, phosphocreatine (PCr), and lactate. We divided the rats into four groups by adjustment of their preictal arterial oxygen tension: group I, PaO2 > 200 mm Hg; group II PaO2 = 50 mm Hg; and group III: PaO2 = 100 mm Hg. We treated a fourth group whose PaO2 = 100 mm Hg with phentolamine to block the 44% rise in blood pressure which occurred with the onset of seizures. PaCO2 was maintained between 30 anf 40 mm Hg in all groups. Brain tissue was sampled rapidly after 0, 10, 20, 30, 60, and 120 seconds of seizures by the freeze-blow technique. With normoxia (PaO2 = 100 mm Hg) or hyperoxia (PaO2 > 200 mm Hg), adenosine increased within ten seconds of the onset of seizures and remained elevated even after 120 seconds. Elevations in inosine and hypoxanthine were delayed compared to the increases in adenosine. A reduction in PaO2 (50 mm Hg) or systemic blood pressure during seizures caused a further augmentation in the increase in brain adenosine levels. During the seizure period, transient changes in adenine nucleotides and energy charge were observed, but PCr remained depressed and lactate continued to rise. The rapid and sustained increase in cerebral adenosine levels, temporally paralleling the changes in cerebral blood flow, supports the role for adenosine in the regulation of cerebral blood flow.
 ...
PMID:Changes in brain adenosine during bicuculline-induced seizures in rats. Effects of hypoxia and altered systemic blood pressure. 677 98

Authors present a 10 year old boy with Lesch-Nyhan syndrome with self-inflicted mutilations to the lips, tongue and interior cheek wall, partially avoided by tooth extraction. Hand lesions were prevented by arm restriction. Born with anoxia and in spite of seizures for several years and a marked muscle stiffness, he is relatively aware of his surroundings. HGPRT activity in blood and hair was nil, while the APRT activity was increased. The mother, a maternal aunt and grandmother are not carriers. Hyperuricemia measured several times and treated with allopurinol is kept between 3 and 4 mg/dl and lastly under 3 mg after increasing dosage. Some years ago, elimination of acid uric stones in urine was observed without hematuria. It seems that recently stone elimination produced pain difficult to evaluate in this patient.
 ...
PMID:[Report of a patient with Lesch-Nyhan syndrome caused by total deficiency of HGPRT and with normal activity in female family members]. 713 25

The objective of the present experiments was to study metabolic correlates to the localization of neuronal lesions during sustained seizures. To that end, status epilepticus was induced by i.v. administration of bicuculline in immobilized and artificially ventilated rats, since this model is known to cause neuronal cell damage in cerebral cortex and hippocampus but not in the cerebellum. After 20 or 120 min of continuous seizure activity, brain tissue was frozen in situ through the skull bone, and samples of cerebral cortex, hippocampus, and cerebellum were collected for analysis of glycolytic metabolites, phosphocreatine (PCr), ATP, ADP, AMP, and cyclic nucleotides. After 20 min of seizure activity, the two "vulnerable" structures (cerebral cortex and hippocampus) and the "resistant" one (cerebellum) showed similar changes in cerebral metabolic state, characterized by decreased tissue concentrations of PCr, ATP, and glycogen, and increased lactate concentrations and lactate/pyruvate ratios. In all structures, though, the adenylate energy charge remained close to control. At the end of a 2-h period of status epilepticus, a clear deterioration of the energy state was observed in the cerebral cortex and the hippocampus, but not in the cerebellum. The reduction in adenylate energy charge in the cortex and hippocampus was associated with a seemingly paradoxical decrease in tissue lactate levels and with failure of glycogen resynthesis (cerebral cortex). Experiments with infusion of glucose during the second hour of a 2-h period of status epilepticus verified that the deterioration of tissue energy state was partly due to reduced substrate supply; however, even in animals with adequate tissue glucose concentrations, the energy charge of the two structures was significantly lowered. The cyclic nucleotides (cAMP and cGMP) behaved differently. Thus, whereas cAMP concentrations were either close to control (hippocampus and cerebellum) or moderately increased (cerebral cortex), the cGMP concentrations remained markedly elevated throughout the seizure period, the largest change being observed in the cerebellum. It is concluded that although the localization of neuronal damage and perturbation of cerebral energy state seem to correlate, the results cannot be taken as evidence that cellular energy failure is the cause of the damage. Thus, it appears equally probable that the pathologically enhanced neuronal activity (and metabolic rate) underlies both the cell damage and the perturbed metabolic state. The observed changes in cyclic nucleotides do not appear to bear a causal relationship to the mechanisms of damage.
 ...
PMID:Metabolic changes in cerebral cortex, hippocampus, and cerebellum during sustained bicuculline-induced seizures. 729 97

Previously, we have shown a significant increase in number of GABAB receptor binding sites in neocortex and thalamus of lethargic (lh/lh) mice, a mutant strain exhibiting absence seizures. This study was performed to test our hypothesis that presynaptic GABAB receptors would inhibit [3H]GABA release to a greater degree in lh/lh mice compared with their nonepileptic littermates (designated +/+). Synaptosomes isolated from neocortex and thalamus of age-matched male lh/lh and +/+ mice were similar in uptake of [3H]GABA. In the neocortical preparation, baclofen dose-dependently inhibited [3H]GABA release evoked by 12 mM KCl, an effect mediated by GABAB receptors. The maximal inhibition (Imax) value was significantly greater (80%) in lh/lh than +/+ mice, whereas the IC50 (3 microM) was unchanged. In the thalamic preparation, the effect of baclofen (50 microM) was 58% less robust in lh/lh mice. Other effects mediated by GABAB receptors (inhibitions in Ca2+ uptake and cyclic AMP formation) were also significantly reduced in thalamic synaptosomes from lh/lh mice. These data suggest a greater presynaptic GABAB receptor-mediated effect in neocortex and a reduced effect in thalamic nuclei of lh/lh mice. It is possible that selective effects of presynaptic GABAB receptors or GABA release in neocortex and thalamic nuclei of lh/lh mice may contribute to mechanisms underlying absence seizures.
 ...
PMID:GABAB receptor-mediated effects in synaptosomes of lethargic (lh/lh) mice. 759 94

We report three neonates with transient hypoparathyroidism with elevated parathyroid hormone (PTH) levels to clarify further the pathogenesis of late neonatal hypocalcemia and calcium homeostasis. Clinical signs were seizures starting at age of 10 and 11 days. The biochemical features were characterized by transient hypocalcemia and hyperphosphatemia due to a high transport maximum of the phosphate/glomerular filtration rate, despite high PTH levels. All had normal magnesium and calcidiol levels (at least 5 micrograms/l) for their age, and this precludes hypoparathyroidism due to low magnesium levels and hyperparathyroidism due to overt vitamin D deficiency. To diagnose pseudohypoparathyroidism type I, intravenous human PTH (1-34) infusions were performed; however, they showed brisk responses of plasma and/or urine cyclic AMP in response to the PTH infusion, but the phosphaturic response to the PTH was sluggish compared to the controls. All three showed an increase in serum alkaline phosphatase activity, suggesting PTH stimulation of osteoblasts. They were treated initially with calcium lactate or (1 alpha)-hydroxycalciol/calcitriol. Their hypoparathyroid condition, however, was transient; they maintained normal serum calcium and PTH levels without medication before the age of 6 months. The etiology, possibly intracellular signal transduction distal to cyclic AMP and/or distinct from adenylate cyclase in the kidney, is developmental and the condition was resolved completely within 6 months of age. We have termed this condition "transient pseudohypoparathyroidism of the neonate".
 ...
PMID:Transient pseudohypoparathyroidism of the neonate. 765 38

Carnitine (beta-hydroxy-gamma-trimethylammonium butyrate) is widely distributed in the body including the nervous system. Its physiological function, viz. a carrier of long-chain fatty acids through the inner mitochondrial membrane, has been well established. In this review, mainly based on our experiments, we discuss the possibility that carnitine may have effects other than the "physiological" function and that it may be a potent protector of the brain. When mice were exposed to ammonia (intraperitoneal injection of ammonium acetate), they developed seizures and concentrations of brain energy metabolites were altered; ATP and phosphocreatine decreased while ADP, AMP, pyruvate and lactate increased. The seizures and changes in brain energy metabolites were clearly suppressed when the mice were pre-treated with carnitine. Furthermore, changes in energy metabolites in the brain caused by severe ischemia (decapitation) were also suppressed by carnitine. Since D-carnitine showed similar effects as those of L-carnitine, the effects seem due to function(s) of carnitine yet to be defined. Intrinsic substances including carnitine appear to deserve further studies for possible use in protecting the brain.
 ...
PMID:Protection of the brain by carnitine. 774 96

The effects of ATP (5-500 microM) were evaluated on the proliferation rate of cultured astrocytes by measuring 3H-thymidine incorporation and by flow cytometric analysis of the cell cycle. Determinations after 16 hours showed that ATP present in the culture medium for the whole period caused a dose-dependent reduction of cell proliferation, while if the exposure to ATP was limited to the first 8 hours, the proliferation was increased (always in a dose-dependent manner). A time course study of 3H-thymidine incorporation showed that, in the presence of ATP, 3H-thymidine was incorporated at a slower rate than in controls; the replacement of the culture medium with an ATP-free fresh medium, at the 8th hour, was followed by a 3H-thymidine incorporation occurring at such a fast rate to overshoot the control values. High performance liquid chromatography (HPLC) analysis, carried out to identify purine compounds present in the culture medium during cell exposure to ATP, indicated that more than 95% of the added ATP was metabolized within 1 hr. Conversely, an increase of purine metabolites was measured, this accumulation being greater at the highest concentrations of added ATP. The presence of high levels of extracellular ATP catabolites suggested that these compounds may act on the regulation of cell replication via the different purine receptors. This hypothesis was tested and confirmed by using agonists and antagonists selective for the P1 and the P2 sites. One hundred microM 2methylthio-ATP (2MeSATP), a P2Y agonist metabolized as fast as ATP, reproduced effects very similar to the ATP-induced ones. On the other hand, the nonhydrolisable ATP analogue, adenosine 5'-(beta, gamma-imido)-triphosphate (AMP-PNP) at 100 microM, induced a mitogenic effect as well as the A2 site stimulation. On the contrary, the activation of A1 receptors by 5 microM R-phenyl-isopropyladenosine (R-PIA) inhibited astrocyte proliferation; moreover, 100 nM 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an A1 site antagonist, reversed the ATP-induced inhibition of cell proliferation. These results indicate that exogenous ATP, as a consequence of its rapid extracellular breakdown, exerts a dual influence on astrocyte proliferation by the involvement of both P1 and P2Y receptors. These findings might be relevant to such pathological conditions of the central nervous system (CNS), as seizures, hypoxia or ischemia, in which great amounts of purines released in the brain can influence a reactive astrocyte proliferative response to injury.
 ...
PMID:Effects of exogenous ATP and related analogues on the proliferation rate of dissociated primary cultures of rat astrocytes. 789 91

DNA binding activities of several transcription factors were evaluated in nuclear extracts from brains of mice which were intracerebroventricularly injected with N-methyl-D-aspartic acid (NMDA) using gel retardation electrophoresis. An injection of NMDA increased binding of both probes for activator protein 1 (AP1) and cyclic AMP response element binding protein (CREB) 1 to 5 h after the injection compared with that of saline, in a dose-dependent manner at doses from 0.05 to 0.4 micrograms. However, no significant alterations were found in binding of probes for other 4 different transcription factors tested following the injection of NMDA up to 4 h after the administration. These included promoter-specific transcription factor, nuclear factor kappa B, activator protein 2 and octamer binding protein. Potentiation of the AP1 and CREB binding was prevented in a dose-dependent manner by the administration of either of the noncompetitive NMDA antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine, the NMDA antagonist D,L-(E)-2-amino-4-propyl-5-phosphono-3-pentenoic acid, the glycine antagonist 5,7-dichlorokynurenic acid, or the proposed polyamine antagonist ifenprodil. In contrast, the AP1 binding was not consistently affected up to 4 h following intracerebroventricular injections of other agonists including DL-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic, kainic, and (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acids, in contrast to the severity of convulsive seizures by the former 2 excitants. These results support the proposal that an intracerebroventricular injection of NMDA may selectively potentiate DNA binding activities of both AP1 and CREB through in vivo activation of the NMDA receptor complex in the murine brain.
 ...
PMID:Molecular biological studies on nuclear transcription factors expressed through the N-methyl-D-aspartate receptor complex. 797 30

Pentylenetetrazole (PTZ) evoked seizures, known to be dependent on stimulation of excitatory amino acids (EAA) receptors, serve as a useful model to study genomic responses to increased brain activity. It is believed that these responses form the basis for long term modifications in neuronal functions. Formation of the AP-1 transcription factor genes and proteins in hippocampal cells is the best known example of a genomic response to PTZ seizures and to an activation of the EAA receptors. In the studies reported herein electrophoretic mobility shift assay (EMSA) was employed to investigate levels of AP-1 DNA binding activity in various regions of the rat brain following PTZ seizures and these levels were compared to the cyclic AMP responsive element (CRE) DNA binding activity. A dramatic increase of the AP-1 DNA binding activity was observed in the hippocampus and in sensory and limbic cortices, and to much lesser extent in the cerebellum. The EMSA supershift method provided an evidence that Jun B and c-Fos and probably Fos B are major components of AP-1 at 2 h after the seizures. In none of the structure investigated, clear modulation of CRE DNA binding activity was noted. These data are discussed in the context of CRE and AP-1 DNA binding crossreactivity.
 ...
PMID:AP-1 and CRE DNA binding activities in rat brain following pentylenetetrazole induced seizures. 803 18


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>