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

Structural analogues of the potent known anticonvulsant agent N-acetyl-DL-alanine N-benzylamide (1a) have been prepared (16 examples). The pharmacological activities of these products were evaluated in the maximal electroshock seizure (MES), the subcutaneous pentylenetetrazole seizure threshold (sc Met), and the rotorod (Tox) tests. The median effective doses (ED50) and the median toxic doses (TD50) for the most active compounds by both intraperitoneal and oral administration are reported. The most active compounds were N-acetyl-DL-phenylglycine N-benzylamide (1d) and N-acetyl-DL-alanine N-m-fluorobenzylamide (1m) along with the parent compound 1a. The ED50 values in the MES test for these three compounds compared well with phenobarbital, while their high TD50 values contributed to their large protective indexes, which approached that of phenytoin. When tested against four convulsant agents, compounds 1a and 1d displayed activity profiles significantly different from those reported for conventionally used antiepileptic drugs.
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PMID:Functionalized DL-amino acid derivatives. Potent new agents for the treatment of epilepsy. 382 Feb 28

Selectively substituted hydantoins 1 (15 examples), 4-hydroxy-2-imidazolidinones 2 (13 examples), 2-imidazolones 3 (10 examples), 2-imidazolidinones 4 (four examples), vicinal diamines 5 (two examples), and simple amino acid derivatives 6 (four examples) have been prepared and evaluated in the maximal electroshock seizure (MES), subcutaneous pentylenetetrazole seizure threshold (sc Met), and rotorod (Tox) tests. The medium effective doses (ED50) and the medium toxic dose (TD50) for the most active compounds are reported. In general, the most pronounced activity was observed for hydantoins 1 and protected amino acids 6. Within each series of compounds, enhanced anticonvulsant activity was often noted for compounds containing an aromatic group one carbon removed from a nitrogen atom. Among the most active compounds observed were the amino acid derivative N-acetyl-D,L-alanine benzylamide (6d) and the two 2-imidazolones 4-methyl-1-(phenylmethyl)-1,3-dihydro-2H-imidazol-2-one (3e) and 1-phenyl-1,3-dihydro-2H-imidazol-2-one (3g). Compound 6d proved to be slightly more potent in the MES test than phenacemide.
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PMID:Effect of structural modification of the hydantoin ring on anticonvulsant activity. 398 20

The efficacy of phenobarbital and primidone against canine epilepsy was compared in a controlled study. Thirty-five dogs showing generalized tonic-clonic seizures (grand mal), treated for a minimum of 6 months, were included in the study; fifteen of these were treated with phenobarbital, the other twenty with primidone. Both drugs were dosed according to the clinical requirement; the daily doses ranged from 5-17 mg/kg phenobarbital and from 17-70 mg/kg primidone. The plasma concentrations of phenobarbital, or of primidone and its metabolites phenobarbital and phenylethylmalondiamide (PEMA), were routinely monitored. Complete control of tonic-clonic seizures for 6 months, at least, was attained in six out of fifteen dogs of the phenobarbital group, and in five out of twenty dogs in the primidone group. A further six dogs on phenobarbital, and seven dogs on primidone, were classified as 'improved', i.e. the rate of seizures was reduced by at least 50%. The rest of the dogs were not improved by the treatment. The difference between the efficacy of phenobarbital and primidone was not significant, but primidone gave rise to signs of liver toxicity in fourteen out of twenty dogs, as indicated by considerable elevations of liver enzyme values (alanine transferase, glutamate dehydrogenase, alkaline phosphatase). Phenobarbital is, therefore, regarded as the drug of first choice for the treatment of canine epilepsy.
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PMID:Therapeutic efficacy of phenobarbital and primidone in canine epilepsy: a comparison. 402 Sep 42

Extracellular levels of amino acids were estimated in dialysates of the rat striatum that were collected 1, 2, and/or more than 5 days after surgery, before (resting release) and during exposure to high K concentrations (50 mM) or electroconvulsive shocks. The resting release of several amino acids (Glu, Asn, Thr, Tau, Tyr, Gly, and Ala) was higher 9 days as compared to 1 day after surgery. In the 1-day preparation the resting release correlated highly with that observed with push-pull cannulas. The correlation with the tissue content of the amino acids was high only when they were divided into two groups (putative transmitters and metabolic intermediates). High K exposure produced increased output of Ala, ethanolamine (Eam), Asp, Glu, Tau, and Gly and a decrease in the egress of Gln 1 or 2 days after surgery. The effects on Asp and Glu had disappeared, and that on Gln reversed after 4-9 days. Electrically induced convulsions produced increased output of Ala, Gln, and Eam 1 or 2 days and 2 weeks after implantation of the probe. Changes were seen not only during but also (and some cases even more prominent) after the seizure. This study shows the usefulness of dialysis to monitor extracellular transmitter amino acids in the striatum of conscious rats (also bilateral dialysis was possible) for only a limited time after implantation of the probe. The dialysis method is suitable for longer time, when metabolic changes in amino acids are to be followed. In addition to transmitter release, glycolysis can be monitored by the measurement of Ala in the dialysate.
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PMID:Amino acids in rat striatal dialysates: methodological aspects and changes after electroconvulsive shock. 404 52

In rabbits, generalized seizures were induced by methoxypyridoxine, and changes in amino acid concentrations of 15 brain regions were investigated before seizure onset and during the course of sustained epileptiform activity. As previously reported, gamma-aminobutyric acid (GABA) concentration decreased preictally in most regions. At the same time, taurine level was elevated in the hypothalamus, thalamus, hippocampus, caudatum, and frontal cortex. After 90 min of seizures, it was significantly decreased in the hypothalamus, periaqueductal grey, substantia nigra, frontal cortex, and cerebellum. Glycine content was reduced preictally only in the substantia nigra; after seizure onset its concentration rose in all brain areas. Glutamate content in the frontal cortex decreased before seizure onset; after 1.5 h of seizures, its concentration in cerebellum, caudatum, and hippocampus was reduced. Aspartate level was decreased in most areas after sustained seizures; in putamen, however, it was elevated. In contrast, glutamine content increased preictally in the superior colliculus and in all brain areas by approximately 200% after 90 min of seizures. Alanine and valine content also rose markedly in most brain areas after prolonged seizures, and threonine showed the same tendency. The single brain regions were observed to respond to methoxypyridoxine in highly individualistic ways. For example, the glycine content of the substantia nigra, which is believed to utilize this amino acid as a neurotransmitter, decreased preictally. The potential importance of the superior colliculus in seizure induction is considered in view of the early rise in glutamine level. The antagonistic preictal behavior of taurine and GABA is discussed with respect to synthesis, uptake from the blood, and antiepileptic properties.
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PMID:Alterations in the content of amino acid neurotransmitters before the onset and during the course of methoxypyridoxine-induced seizures in individual rabbit brain regions. 613 13

Free amino acid patterns of cerebrospinal fluid in infants and children with various types of convulsive disorders were compared with those in age-matched normal subjects. The total free amino levels in Lennox syndrome were higher than the normal values, and those in infantile spasms controlled by ACTH were higher than those in uncontrolled infantile spasms. Although the levels of only one or two amino acids in tonic-clonic seizure, focal seizure and febrile seizure were higher or lower than those of the controls, the levels of 8 amino acids in infantile spasms were lower and those of 10 amino acids in Lennox syndrome were generally higher compared to the controls. Among amino acids in CSF of children with tonic-clonic seizure, infantile spasms or Lennox syndrome, only the ornithine level was commonly lower than that of the controls. After the treatment, in tonic-clonic seizure, the levels of taurine, asparagine and glycine were increased, and in infantile spasms, those of asparagine, glutamine, glycine, alanine, phenylalanine, lysine and arginine were increased while that of taurine was decreased. These results suggest that each type of convulsive disorder shows the specific amino acid pattern, and the effects of anticonvulsants may be partially understood through the changes of the free amino acid patterns in the brain.
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PMID:Amino acid metabolism in the brain with convulsive disorders. Part 3: Free amino acid patterns in cerebrospinal fluid in infants and children with convulsive disorders. 632 17

The subcellular distribution of amino acids was compared in brains of genetically seizure-susceptible (SS) and genetically seizure-resistant (SR) rats. The total taurine content (mumol/brain) in the P2B, or synaptosomal, fraction in SS rats was only 37% of that of SR rats. Glutamate, glutamine, glycine, alanine, and gamma-aminobutyric acid (GABA) contents were unaltered. No alterations in total content were found in other subcellular fractions for the amino acids studied. SS animals that had never been stimulated to audiogenic seizure had decreased concentrations of taurine (nmol/mg protein) in the P2, P2B, and P2C fractions as compared with SR animals. These fractions contain crude synaptosomes, enriched synaptosomes, and enriched mitochondria, respectively. Phosphoethanolamine concentrations were also decreased in the P2B fractions, but concentrations of other amino acids were unaltered, as compared with SR animals. Twenty-four hours after the intracerebroventricular injection of taurine (6 mumol) in SS animals that had never been convulsed, taurine concentrations were significantly increased in whole brain homogenate and P2 and P2B fractions as compared with SS animals not given taurine. This treatment left unaltered the concentrations of glutamate, glutamine, GABA, and glycine in brain homogenate and P2 fraction. Because decreases in taurine concentration were seen in animals that had not been convulsed, these alterations are intrinsic to the SS strain and are not a consequence of convulsive activity. In view of the antiepileptic action of taurine, and the fact that an impairment of taurine transport in the brain of SS rats had previously been demonstrated, we suggest that a defect in the biochemistry of taurine is partially responsible for the seizure susceptibility of the SS rat.
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PMID:Subcellular distribution of neuroactive amino acids in brains of genetically epileptic rats. 647 8

The activities of lipoyl dehydrogenase, aspartate transaminase, and alanine transaminase, and levels of lactate were estimated in cerebral cortex, cerebellum, and brainstem of rats intoxicated acutely with tetraethyl lead and chronically with lead acetate. A significant inhibition of lipoyl dehydrogenase was observed in both groups of animals, whereas transaminase activities were increased in inorganic lead toxicity. Oxidative decarboxylation and anaplerosis of pyruvate was assessed in brain slices using [1-14C]pyruvate. Pyruvate dehydrogenase activity was decreased in both organic and inorganic lead toxicity, whereas labelling of aspartate and alanine was increased in inorganic lead toxicity. In studies in vitro, lead acetate showed a more significant effect than tetraethyl lead. The higher anaerobic metabolism in inorganic lead toxicity, as evidenced by increased anaerobic lactate production by brain slices, could either be an adaptive mechanism or be due to the delayed maturation of brain in the developing rat. Such a mechanism does not occur in acute organic lead toxicity, as the compound brings about massive and rapid degenerative changes in brain, resulting in convulsive seizures and death of the animals.
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PMID:Pyruvate metabolism in the brain of young rats intoxicated with organic and inorganic lead. 654 9

A neurochemical evaluation of beagle dogs with naturally occurring spontaneous generalized convulsive seizures was performed. Amino acid profiles of serum, cerebrospinal fluid (CSF), and biopsied cerebral cortex from epileptic dogs were compared with those from seizure-free siblings. No differences in absolute levels were noted. However, when levels were normalized as a percent of total free amino acids, seizures was performed. Amino acid profiles of serum, cerebrospinal fluid (CEF), and biopsied cerebral cortex from epileptic dogs were compared with those seizure-free siblings. No differences also the two groups differed in certain respects. Ten significant correlations between amino acid pairs appeared in epileptic dogs, but only one was seen in seizure-free animals. Seven of these ten correlations involved glutamate or taurine. It was noted that the highly correlated amino acids (taurine, glutamate, glycine, glutamine, alanine) all utilize sodium-dependent membrane transport processes. The sum of glutamate, aspartate, and glycine levels (competing sodium-dependent high-affinity systems) was significantly lower in epileptic beagles. Since this difference was noted in serum but not CSF or brain, it may indicate a diminished capacity of sodium-dependent high-affinity renal transport for acidic and certain small neutral amino acids.
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PMID:Amino acid changes in a genetic strain of epileptic beagle dogs. 677 70

The cardiovascular effects of opioid peptides have been studied. Leucine-enkephalin (Leu-ENK) produced blood pressure (BP) increases following administration into the lateral brain ventricles (i.v.t.), into the cisterna magna (i.c.i.), and following intravenous (i.v.) administration. Heart rate (HR) increases were observed following all routes of administration (threshold for BP and HR effects at 0.3 nmole, maximum at 360 nmoles). The cardiovascular effects were independent of generalized seizures, which may occur at higher doses of enkephalins (ENK). D-alanine-enkephalin (D-Ala-ENK) attenuated the vagal component of the baroreceptor reflex in cats. This was indicated by the findings that HR did not decrease following D-Ala-ENK-induced BP increases and that the compensatory decreases in HR following i.v. pressor doses of angiotensin II (ANG II) were markedly attenuated in cats treated with i.v.t. D-Ala-ENK. Naloxone inhibited the BP and HR effects following i.c.i. and i.v., but not following i.v.t., administration of Leu-ENK. The i.v.t. Leu-ENK effect were inhibited by beta-adrenergic receptor blockade. Bratteboro rats homozygous for hereditary diabetes insipidus with total absence of antidiuretic hormone (ADH) synthesis responded with BP decreases following i.v.t. Leu-ENK, while BP increases were observed in control Long-Evans rats. Blood pressure increases to i.v.t. Leu-ENK were markedly greater in spontaneously hypertensive rats of the stroke-prone strain (SHR-sp) than in normotensive control rats; SHR-sp exhibit a humoral pattern of increased ADH, ACTH, and catecholamines, presumably due to central peptidergic stimulation. The known effects of opioid peptides on these hormones and the observed cardiovascular responses suggest a possible participation of this peptide system in the maintenance of high BP in the SHR-sp.
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PMID:Enkephalin effects on blood pressure, heart rate, and baroreceptor reflex. 739 23


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