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)

Exposing the developing brain to the N-methyl-D-aspartate (NMDA) receptor antagonist phencyclidine (PCP) has been shown to cause deficits in neurobehavioral functions, particularly on learning and memory and seizure sensitivity. Besides acting as a noncompetitive NMDA antagonist, PCP at high doses is known to affect the dopaminergic system. The present study assessed the effect of postnatal PCP treatment on locomotor activity and striatal dopamine (DA) D(2) receptor. Male and female rat pups were injected intraperitoneally (i.p.) with one of three doses of PCP (1, 3 and 5 mg/kg) or saline from postnatal day (PD) 5 to PD 15. Control and PCP-treated rats were given a challenge dose of PCP (10 mg/kg) as adults, and their locomotor behaviors--locomotion, stereotypy and ataxia--were scored. Postnatal PCP treatment did not have any significant effect in either sex on any of the PCP-induced locomotor behavioral paradigms studied. Separate groups of male and female rats were treated daily with saline or PCP (5 mg/kg i.p.) from PD 5 to PD 15 and sacrificed either as juveniles (PD 21) or adults, and D(2) receptor binding was measured in their striata. Striatal D(2) receptor density in juvenile and adult male postnatal PCP-treated rats did not differ from saline-treated controls. Adult female PCP-treated rats showed a slight but significant reduction in the maximal binding of striatal D(2) receptors. There was no effect of postnatal PCP on striatal D(2) receptor binding in female juvenile rats. These results support the hypothesis that blocking the developing NMDA receptor minimally affects PCP-induced locomotor behavior and the striatal D(2) receptor.
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PMID:Effects of postnatal PCP treatment on locomotor behavior and striatal D2 receptor. 1266 9

Elucidation of the metabolism and pharmacology of 1,2,3-triazolines (TRs) led to the identification of the triazoline pharmacophore and the evolution of the aminoalkylpyridines (AAPs). The AAPs have no activity in the scMet test but are highly effective in the MES seizure test by the oral route. The AAPs bind to the sigma(1) receptor with low affinity, but high selectivity. They impair Glu release to the same extent as the triazolines and afforded a high degree of protection in the kindled rat. They show no affinity for the NMDA/PCP receptor sites; thus the toxic side effects of NMDA antagonists are absent in the sigma selective AAPs. Variations of the heterocyclic unit, the alkyl chain and the amino group in the AAP leads, indicated that the 4-pyridyl substituent along with a methyl (alkyl) group, and a 4-C1, 3-C1 or 3,4-C1(2) substitution on the N-phenyl group, afforded the most active compounds. Amino group modification by acylation did not improve activity. The hydrazone compounds were the most active. Although the AAPs are very effective in the MES and the kindling models of epilepsy, they showed only low to moderate activity in protecting neuronal cells in stroke-induced cerebral ischemia. In the case of the TR compounds, even the least effective TR afforded 47% protection from neuronal injury. It is not known at this point, whether activity in both the MES and scMet tests, which would imply a role for both Glu and GABA, is a prerequisite for antiischemic activity.
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PMID:Aminoalkylpyridines (AAPs), triazoline metabolite analogues, as anticonvulsants highly effective in the MES test. 1287 Oct 88

A dextromethorphan (3-methoxy-17-methylmorphinan) analog, dimemorfan (3-methyl-N-methylmorphinan) that is not metabolized to dextrorphan [3-hydroxy-17-methylmorphinan, which induces phencyclidine (PCP)-like behavioral effects], attenuates maximal electroshock seizures. However, the pharmacological mechanism of action of dimemorfan remains to be determined. In this study, we assessed the locomotor activity mediated by these morphinans. Circling behavior was pronounced in mice treated with PCP or dextrorphan, while animals treated with dextromethorphan exhibited moderate behaviors. Dimemorfan did not show any significant behavioral effects. We used BAY k-8644 (an L-type Ca2+ channel agonist in the dihydropyridine class) to explore the effects of dextromethorphan and dimemorfan on the convulsant activity regulated by calcium channels. Intracerebroventricular injection of BAY k-8644 (37.5 microg) significantly induced seizures in mice. As with dextromethorphan (6.25 or 12.5 mg/kg), dimemorfan (6.25 or 12.5 mg/kg) pretreatment significantly attenuated BAY k-8644-induced seizures in a dose-dependent manner. BAY k-8644-induced seizure activity paralleled increased expression of c-fos and c-jun, AP-1 DNA binding activity, and fos-related antigen immunoreactivity. Pretreatment with dextromethorphan or dimemorfan significantly attenuated the expression induced by BAY k-8644. Therefore, our results suggest that the anticonvulsant effects of dextromethorphan and dimemorfan are mediated, at least in part, via L-type calcium channel, and that dimemorfan is equipotent to dextromethorphan in preventing BAY k-8644-induced seizures, while it lacks behavioral side effects related to psychotomimetic reactions.
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PMID:Dimemorfan prevents seizures induced by the L-type calcium channel activator BAY k-8644 in mice. 1508 42

The expression of the alpha7-nicotinic acetylcholine receptor is diminished in selected brain areas of patients with schizophrenia. This diminished expression may account for the pathophysiological deficits of sensory inhibition and smooth pursuit eye movement performance in these patients. Furthermore, the deficits in sensory inhibition and smooth pursuit eye movement performance in schizophrenia appear to be inherited in an autosomal dominant fashion; thus, the "alpha7-nicotinic acetylcholine receptor-deficiency" may be a necessary condition for expression of schizophrenia. This deficit has encouraged speculation about the possible therapeutic benefit of selective alpha7-nicotinic acetylcholine receptor agonist interventions in this disorder. In view of this, we sought to examine the effect of anabasine, a selective alpha7-nicotinic acetylcholine receptor agonist, on popping behavior in mice elicited by MK-801. MK-801, a high affinity analogue of phencyclidine (PCP), is a noncompetitive N-methyl-D-aspartic acid (NMDA) receptor antagonist that binds to the hydrophobic domain of this ligand-gated channel. PCP is known to precipitate a schizophreniform psychosis in susceptible individuals, causing productive (e.g. hallucinations) deficit (e.g. affective blunting, amotivation, and social withdrawal), cognitive and motor symptoms similar to those seen in naturally-occurring schizophrenia. Behaviors elicited by MK-801 in mice reflect a pharmacologically-induced state of NMDA receptor hypofunction (NRH), which has been proposed to exist in schizophrenia. Compounds that attenuate MK-801-elicited behaviors, which are identified in this animal model, may have the potential to treat schizophrenia, including deficit and cognitive symptoms. In the current study, anabasine attenuated MK-801-elicited popping at a dose that did not cause clonic seizures. The development of alpha7-nicotinic acetylcholine receptor agonist interventions for schizophrenia must consider their potential liability to elicit seizure activity.
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PMID:Anabasine, a selective nicotinic acetylcholine receptor agonist, antagonizes MK-801-elicited mouse popping behavior, an animal model of schizophrenia. 1526 37

The involvement of the septohippocampal system on the impaired sensorimotor gating induced by phencyclidine (PCP) or by an electrically induced hippocampal seizure was examined in behaving rats. An impaired sensorimotor gating, measured by prepulse inhibition (PPI) of the acoustic startle response, was observed following a hippocampal afterdischarge (AD) or systemic injection of PCP and was accompanied with an increase in hippocampal gamma waves (30-70 Hz). The medial septum infusion with muscimol (0.25 microg), a GABA(A) receptor agonist, 15 min prior to PCP or a hippocampal AD, prevented the impairment of sensorimotor gating and the increase in gamma waves. By itself, muscimol (0.25 microg) injection into the medial septum did not affect PPI, although it significantly suppressed spontaneous gamma waves. In order to identify subpopulations of neurons mediating the sensorimotor gating deficit and the hippocampal gamma wave increase, 0.14-0.21 microg of p75 antibody conjugated to saporin (192 IgG-saporin) was injected into the medial septum to selectively lesion the septohippocampal cholinergic neurons. Neither the PPI deficit nor the gamma wave increase induced by PCP or a hippocampal AD was affected by 192 IgG-saporin lesion of the medial septum. It is concluded that increase in neural activity in the medial septum participates in the impairment of sensorimotor gating and the increase in hippocampal gamma waves induced by PCP or a hippocampal AD. It is suggested that the GABAergic but not the cholinergic septohippocampal neurons mediate the sensorimotor gating deficit.
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PMID:The medial septum mediates impairment of prepulse inhibition of acoustic startle induced by a hippocampal seizure or phencyclidine. 1532 89

Patients with primary brain tumors and those with cerebral metastases are at risk throughout their illness for several major medical problems, including vasogenic edema, seizures, and symptomatic venous thrombosis. In turn, the corticosteroids, anti-epileptic drugs, and anticoagulants used to treat these problems may produce significant adverse effects and result in important drug-drug interactions that may complicate chemotherapy. Although few Class I studies address any of these issues, guidelines can be offered to maximize quality of life and minimize hospital readmissions. Optimal management of brain edema involves minimizing corticosteroid use and tapering the steroid dose slowly to avoid steroid withdrawal symptoms. Prophylaxis of Pneumocystis pneumonia is necessary for patients requiring corticosteroids for more than 1 month. Anti-epileptic drugs (AEDs) should be avoided unless patients experience seizures. If possible, non-CTY (P450) enzyme-inducing drugs should be chosen. AED levels should be obtained frequently during corticosteroid taper. Multimodality venous thrombosis prophylaxis should begin at the time of the original surgery with external leg compression and unfractionated subcutaneous heparin or a low molecular weight heparin (LMWH). Brain tumor patients with symptomatic venous thrombosis or pulmonary embolism can be anticoagulated safely with warfarin or with LMWH, and LMWHs are preferable from the standpoints of efficacy, safety, and convenience for long-term outpatient treatment of venous thrombosis. Clinicians should be aware of potential drug-drug interactions between prescribed AEDs and chemotherapy and possible interactions with complementary and alternative therapies chosen by their patients. They also should be aware of interventions to minimize late sequelae of brain tumors and their treatment, including cognitive decline, depression, and increased stroke risk.
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PMID:Treatment of Medical Complications in Patients with Brain Tumors. 1596 95

Co-trimoxazole (trimethoprim-sulfamethoxazole) is a commonly prescribed antimicrobial agent. Although it is well tolerated in most patients, serious adverse events related to its use have been described. Hypoglycaemia is a rare but potentially life-threatening complication of therapy. We describe a case of refractory hypoglycaemia complicated by seizure associated with co-trimoxazole for the treatment of Pneumocystis carinii pneumonia in a patient with AIDS. We also review 13 previously reported cases of co-trimoxazole-induced hypoglycaemia. Among this patient population, renal insufficiency was the most prevalent predisposing risk factor (93%). The mean daily dose of co-trimoxazole was 4.5 double strength (160 mg trimethoprim/800 mg sulfamethoxazole) tablets per day. Serum insulin levels were raised or inappropriately normal in 88% of cases in which they were measured, suggesting a sulfonylurea-like effect of co-trimoxazole as the mechanism of hypoglycaemia. All cases required intravenous glucose administration, and 43% experienced protracted (>12 hours) hypoglycaemia. Dosage adjustments should be made when prescribing co-trimoxazole to patients with renal dysfunction.
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PMID:Severe and protracted hypoglycaemia associated with co-trimoxazole use. 1650 May 99

Abnormalities of NMDA receptor-mediated neurotransmission are involved in the pathophysiology of schizophrenia, Alzheimer's disease, substance abuse and seizure disorders. The NMDA receptor is implicated in schizophrenia because phencyclidine (PCP), a noncompetitive NMDA receptor antagonist, binds to a hydrophobic domain within the channel, precipitating a schizophreniform psychosis in susceptible persons. Pharmacological, environmental, and genetic variables alter NMDA receptor-mediated neurotransmission. Inbred mouse strains differ in their sensitivity to some of the behavioral effects of MK-801 (dizocilpine), a PCP analogue. The NMDA receptor complex in the BALB/c strain could reflect a unique stoichiometric combination of receptor subunits resulting in a higher proportion of the channels in the open configuration, a higher affinity of MK-801 for its hydrophobic channel domain, and/or a combination of the above. The BALB/c mouse strain, "stressed" mice, and behavioral consequences of MK-801 administration represent models of altered glutamatergic neural transmission. We were interested in examining the effect of stress on the modulatory properties of d-serine and sarcosine. d-Serine is a naturally occurring glycine agonist that modulates the ability of l-glutamate to influence the opening of the NMDA receptor-associated ionophore, and sarcosine is a naturally occurring glycine reuptake inhibitor. The data suggest that 24h after stress, d-serine and sarcosine interact synergistically to reduce MK-801's ability to antagonize electrically precipitated tonic hindlimb extension. Under conditions of stress, modulatory effects of d-serine and sarcosine on the antiseizure effect of MK-801 are observed that are not apparent in the nonstress condition. The results could be relevant to the development of glycinergic interventions for the treatment of neuropsychiatric disorders.
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PMID:Modulatory effects of d-serine and sarcosine on NMDA receptor-mediated neurotransmission are apparent after stress in the genetically inbred BALB/c mouse strain. 1671 29

Aberrant glutamatergic neurotransmission may underlie the pathogenesis of schizophrenia and metabotropic glutamate receptors (mGluRs) have been implicated in the disease. We have established the localization of the group III mGluR subtype, mGluR8, in the human body and investigated the biological effects of the selective mGluR8 agonist (S)-3,4-dicarboxyphenylglycine ((S)-3,4-DCPG) in schizophrenia-related animal models. The mGlu8 receptor has a widespread CNS distribution with expression observed in key brain regions associated with schizophrenia pathogenesis including the hippocampus. (S)-3,4-DCPG inhibited synaptic transmission and increased paired-pulse facilitation in rat hippocampal slices supporting the role of mGluR8 as a presynaptic autoreceptor. Using the rat Maximal Electroshock Seizure Threshold (MEST) test, (S)-3,4-DCPG (30 mg/kg, i.p.) reduced seizure activity confirming the compound to be centrally active following systemic administration. (S)-3,4-DCPG did not reverse (locomotor) hyperactivity induced by acute administration of phenylcyclidine (PCP, 1-32 mg/kg, i.p.) or amphetamine (3-30 mg/kg, i.p.) in Sprague-Dawley rats. However, 10 nmol (i.c.v.) (S)-3.4-DCPG did reverse amphetamine-induced hyperactivity in mice although it also inhibited spontaneous locomotor activity at this dose. In addition, mGluR8 null mutant mouse behavioral phenotyping revealed an anxiety-related phenotype but no deficit in sensorimotor gating. These data provide a potential role for mGluR8 in anxiety and suggest that mGluR8 may not be a therapeutic target for schizophrenia.
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PMID:Evaluation of the mGlu8 receptor as a putative therapeutic target in schizophrenia. 1743 65

This work was undertaken to elucidate some aspects of the epidemiology of Pneumocystis pneumonia (PP). We studied 42 mechanically ventilated, human immunodeficiency virus (HIV)-negative, severely ill neonates treated at an intensive care unit. The study group included 40 premature neonates and two mature neonates with lethal congenital defects. Progressive respiratory dysfunction in PP necessitated mechanical ventilation. Infection was usually noticeable on the 22nd day of life or after 12 days of ventilation. The usual manifestations included apnea, pallor, copious frothy sputum, seizures, and feeding difficulties. The diagnosis was established by detecting Pneumocystis jiroveci cysts in bronchial lavage fluid specimens (88.1% sensitivity). PP was managed with cotrimoxazole and pentamidine combination therapy administered over 14 days. No clinical improvement was noted in four neonates and three of them died during therapy. Prematurity and protracted mechanical ventilation are two risk factors for P. jiroveci infection in severely ill neonates in an intensive care unit.
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PMID:Prematurity and protracted mechanical ventilation as risk factors for Pneumocystis jiroveci infection in HIV-negative neonates in an intensive care unit. 1790 15


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