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)

Physical dependence on ethanol can result in seizure susceptibility during ethanol withdrawal. In rats, generalized tonic-clonic seizures are precipitated by auditory stimulation during the ethanol withdrawal syndrome. Excitant amino acids (EAAs) are implicated as neurotransmitters in the inferior colliculus and the brain stem reticular formation, which play important roles in the neuronal network for genetic models of audiogenic seizures (AGSs). Ethanol blocks the actions of EAAs in various brain regions, including the inferior colliculus. In this study, dependence was produced by intragastric administration of ethanol for 4 days. During ethanol withdrawal, AGSs were blocked by systemic administration of competitive or noncompetitive NMDA antagonists 3-((+/-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) or dizocilpine (MK-801). Focal microinjections of NMDA or non-NMDA antagonists into the inferior colliculus or the pontine reticular formation also inhibited AGSs. MK-801 was the most potent anticonvulsant systemically. When injected into the inferior colliculus, CPP had a more potent anticonvulsant effect than either MK-801 or the non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione. The inferior colliculus was more sensitive than the pontine reticular formation to the anticonvulsant effects of both competitive NMDA and non-NMDA antagonists. The results of the present support the idea that continued ethanol administration may lead to development of supersensitivity to the action of EAAs in inferior colliculus and pontine reticular formation neurons. This may be a critical mechanism subserving AGS susceptibility during ethanol withdrawal.
 ...
PMID:Seizures during ethanol withdrawal are blocked by focal microinjection of excitant amino acid antagonists into the inferior colliculus and pontine reticular formation. 769 44

Ethanol withdrawal (ETX) in ethanol-dependent rats results in susceptibility to seizures, including generalized tonic-clonic audiogenic seizures (AGS). The inferior colliculus (IC) is strongly implicated in AGS initiation during ETX, but IC neuronal mechanisms subserving AGS are unclear. The present study examined IC (central nucleus) single neuronal firing during repeated (4 day) intragastric ethanol administration and during ETX. This involved microwire electrodes implanted chronically into freely moving rats and acoustic stimulation in intensities up to 105 dB SPL. During initial ethanol administration the animals were stuporous, and IC spontaneous neuronal firing and acoustically evoked firing at high stimulus intensities were significantly reduced. This firing reduction is consistent with the action of ethanol to enhance gamma-aminobutyric acid (GABA)-mediated inhibition, which is prominent in IC neurons at high stimulus intensities. During ETX the animals were agitated, and spontaneous IC neuronal firing and acoustically evoked firing at all stimulus intensities were significantly increased during the period of AGS susceptibility. Previous studies indicate that IC neuronal responses are tightly regulated by GABA and glutamate. The IC firing increases during ETX in the present study may involve the down-regulation of GABAA receptors and supersensitivity of glutamate receptors reported to occur during ETX. Previous studies also indicate that focal blockade of GABAA receptors or activation of glutamate receptors produces AGS susceptibility in normal rats. Therefore, the IC neuronal firing increases observed in the present study may play a critical role in initiation of AGS during ethanol withdrawal.
 ...
PMID:Ethanol withdrawal induces increased firing in inferior colliculus neurons associated with audiogenic seizure susceptibility. 772 Aug 30

Ethanol, acutely, is a potent and selective inhibitor of the function of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor in primary cultures of cerebellar granule cells. The effect of ethanol can be reversed by high concentrations of glycine, and non-equilibrium ligand binding studies in brain membrane preparations suggest that ethanol may act by decreasing the frequency of ion channel opening. After chronic consumption of ethanol by animals, the number of NMDA receptors (measured by ligand binding) is increased in many brain areas. Similarly, NMDA receptor function is increased in cerebellar granule cells exposed chronically to ethanol. In the intact animal, this receptor up-regulation may be associated with ethanol withdrawal seizures, which are attenuated by uncompetitive antagonists at the NMDA receptor. In contrast to ethanol, barbiturates have a greater inhibitory effect at the kainate subtype of glutamate receptor than at the NMDA receptor. After chronic barbiturate ingestion, kainate binding is decreased in certain brain areas, while ligand binding to the NMDA receptor is increased. Overall, the pattern of brain area-specific effects of barbiturates on NMDA and kainate receptor function is quite distinct from that of ethanol.
 ...
PMID:Ethanol, sedative hypnotics and glutamate receptor function in brain and cultured cells. 774 22

This study investigated the ability of hyperbaric exposure to antagonize ethanol's anticonvulsant effect on isoniazid (INH)-induced seizures. Drug-naive, male C57BL/6 mice were injected intraperitoneally with saline, 1.5, 2.0, or 2.5 g/kg ethanol followed immediately by an intramuscular injection of 300 mg/kg of INH. The mice were then exposed to either 1 atmosphere absolute (1 ATA) air, 1 ATA helium-oxygen gas mixture (heliox), or 12 ATA heliox at temperatures that offset the hypothermic effects of helium. Ethanol increased the latency to onset of myoclonus in a dose-dependent manner. Exposure to 12 ATA heliox antagonized ethanol's anticonvulsant effect at 2.0 and 2.5 g/kg, but not at 1.5 g/kg. Ethanol also increased the latency to onset of clonus in a dose-dependent manner beginning at 2.0 g/kg. Exposure to 12 ATA heliox antagonized this anticonvulsant effect. When exposed to 12 ATA heliox, the blood ethanol concentrations at time to onset of myoclonus were significantly higher in mice treated with 2.5 g/kg of ethanol as compared with blood ethanol concentrations of mice exposed to 1 ATA air. These findings extend the acute behavioral effects of ethanol known to be antagonized by hyperbaric exposure and support the hypothesis that low-level hyperbaric exposure blocks or reverses the initial action(s) of ethanol leading to its acute behavioral effects.
 ...
PMID:Low-level hyperbaric antagonism of ethanol's anticonvulsant property in C57BL/6J mice. 784 5

Ethanol-dependent mice were treated with the 5-HT3 antagonist MDL 72222 after withdrawal from ethanol. Treatment with unit doses (0, 5.6, 10, and 17.0 mg/kg) of MDL 72222 at 0, 4, and 7 hr after withdrawal dose-dependently exacerbated the severity of ethanol withdrawal seizures. Treatment with a single dose (17 mg/kg) of MDL 72222 at 5 hr after withdrawal also exacerbated the severity of ethanol withdrawal seizures. Ethanol naive mice treated with MDL 72222 (56 mg/kg) did not display any seizures. Treatment with another 5-HT3 antagonist, ICS 205-930 (23 and 46 mg/kg), or the 5-HT2 receptor antagonist ketanserin, did not affect ethanol withdrawal seizures. The findings suggest MDL 72222 selectively enhances sensitivity to withdrawal seizures following chronic ethanol exposure.
 ...
PMID:The 5-HT3 antagonist MDL-72222 exacerbates ethanol withdrawal seizures in mice. 804 47

Recent studies have demonstrated that ethanol is a potent blocker of N-methyl-D-aspartate (NMDA) receptor mediated responses. It is well known that neuroplasticity processes depend on the activation of the NMDA type of excitatory amino acid receptor. We have used an in vitro model of electrographic seizures (EGS), a neuroplasticity process, to examine the effect of varying ethanol concentrations. In the present experiment, slices of rat hippocampus were electrically stimulated to produce stimulus train-induced epileptiform bursting in area CA3. EGS duration and intensity was enhanced by 10 mM ethanol, whereas increasing the concentration of ethanol (60-300 mM) attenuated established EGSs. Ethanol also raised the threshold to elicit an EGS. Removal of low ethanol concentrations resulted in a hyperexcitable state, with increased EGS duration and intensity. These results reflect acute biphasic effects of ethanol across concentrations, and withdrawal hyperexcitability. The effects of ethanol on EGSs, at concentrations which elicit intoxication but not anesthesia (< 75 mM), resemble the actions produced by NMDA antagonists on EGSs. Therefore the effects of ethanol on stimulus train-induced EGSs may be mediated through an action at the NMDA receptor complex.
 ...
PMID:Proconvulsant and anticonvulsant properties of ethanol: studies of electrographic seizures in vitro. 809 14

Mice selectively bred to be Withdrawal Seizure-Prone (WSP) or Seizure-Resistant (WSR) after chronic ethanol administration have been reported to be differentially sensitive to the anticonvulsant and proconvulsant effects on alcohol withdrawal of drugs interacting with glutamate receptors. Several behavioral effects of the noncompetitive glutamate receptor antagonist, dizocilpine, were determined in WSP and WSR mice to see whether their differential sensitivity generalized to effects unrelated to seizures, and to see whether it was only apparent during ethanol withdrawal. Dizocilpine potentiated the loss of righting reflex induced by ethanol, and dose-dependently stimulated habituated and nonhabituated open field activity. WSP and WSR mice were equally sensitive to these effects of dizocilpine. Pretreatment with dizocilpine increased the transcorneal amperage necessary to produce maximal electroshock seizures: WSR mice were more sensitive than WSP to this effect. Ethanol withdrawal (i.e., testing 6 h after a 24-h exposure to ethanol vapor) and dizocilpine had several effects on mice tested in the hole-in-wall apparatus. Several differences between WSP and WSR mice were also found, but in no case did dizocilpine differentially affect ethanol-withdrawing WSP and WSR mice. Across these experiments, differences between WSP and WSR mice in response to dizocilpine were rather specific. For some responses, WSP and WSR mice were equally sensitive, but only in the seizure-related measure assessed were naive WSR mice more sensitive than WSP.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effects of dizocilpine in withdrawal seizure-prone (WSP) and withdrawal seizure-resistant (WSR) mice. 820 61

Neuronal Ca2+ channels have been shown to be involved in both alcohol drinking behavior in rats and nonhuman primates and in the manifestation of alcohol withdrawal symptoms in rodents. Experiments were performed to determine the effect of a single injection of levemopamil, a novel Ca2+ channel antagonist with antiserotonergic [5-hydroxytryptamine2 (5-HT2)] properties, on alcohol preference and alcohol withdrawal symptoms in alcohol-preferring (P) and Wistar rats, respectively. P rats were individually housed and provided free access to food, water, and a solution of 10% (v/v) ethanol. Ethanol, food, and water intakes were measured daily. After establishing a stable baseline, P rats were injected with levemopamil (0, 3.3, 10, 15, and 20 mg/kg) and their food, water, and alcohol intakes measured 24 h later. In a separate experiment, the ability of acute and chronic (12 consecutive days) administrations of levemopamil to suppress alcohol withdrawal symptoms in chronically alcohol-treated rats was studied. In addition, the effects of levemopamil on the level of monoamines in different areas of the brain, as well as its action in alcohol metabolism, were examined. Our findings showed that a single administration of levemopamil (10, 15, and 20 mg/kg) significantly and dose-dependently attenuated alcohol intake and increased water intake in P rats. Both acute and chronic treatment with levemopamil reduced the alcohol withdrawal symptoms, overall seizure scores, and proportion of rats seizing. A single injection of levemopamil produced a clear, but not significant, trend to increase the 5-HT turnover rate in certain brain areas. This drug did not influence the pharmacokinetics of alcohol.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Reduction of spontaneous alcohol drinking and physical withdrawal by levemopamil, a novel Ca2+ channel antagonist, in rats. 826 91

Previous research from this laboratory has indicated that animals chronically exposed to ethanol and then withdrawn exhibit a variety of symptoms of central nervous system hyperexcitability that occur in unique clusters. These clusters of symptoms were observed to differ in their duration and in the time of onset relative to the time of ethanol withdrawal. In addition, the observed clusters of spontaneous seizure events in these animals were seen to correlate with differences in sensitivity to seizure-inducing treatments. These results suggest that seizure sensitivity during ethanol withdrawal may indicate the involvement of multiple, independent, neuronal mechanisms. To investigate this possibility further, the following study examined the sensitivity of ethanol-withdrawn animals to seizures induced by the glycine antagonist strychnine. Seizure sensitivity to strychnine was evaluated at the same times following ethanol withdrawal when animals were previously seen to show the differential occurrence of spontaneous seizure events and also differences in sensitivity to picrotoxin-induced seizures. Ethanol-withdrawn animals did not differ in their responses to strychnine compared with ethanol-naive controls at any of the times tested. This lack of change in seizures induced by antagonism of glycine inhibition occurred in spite of the increased sensitivity of similarly treated animals to picrotoxin-induced seizures at the same test times. These data suggest that chronic ethanol exposure and withdrawal may not significantly after the function of glycinergic inhibitory neurotransmission and that the ethanol withdrawal syndrome is indicative of alterations in specific neuronal mechanisms rather than of a generalized state of central nervous system hyperexcitability.
 ...
PMID:Sensitivity to strychnine seizures is unaltered during ethanol withdrawal. 827 62

Ethanol intoxication has been widely reported as a cause of lactic acidosis. To determine the frequency and severity of ethanol-induced lactic acidosis, patients who presented to an emergency department with a clinical diagnosis of acute ethanol intoxication and a serum ethanol concentration of at least 100 mg/dL were studied. Arterial blood was sampled for lactate and blood gas determinations. A total of 60 patients (mean age, 41 years) were studied. Twenty-two patients sustained minor trauma. Ethanol concentrations ranged from 100 to 667 mg/dL (mean, 287 mg/dL). Lactate concentrations were abnormal (> 2.4 mmol/L) in seven patients (11.7%). In all cases, blood lactate was less than 5 mmol/L. Of the patients with elevated lactate, other potential causes for lactic acidosis, including hypoxia, seizures, and hypoperfusion, were also present. Only one case with elevated blood lactate concentration had associated acidemia. Significant elevations of blood lactate are uncommon in acute ethanol intoxication. In patients with ethanol intoxication who are found to have lactic acidosis, other etiologies for the elevated lactate level should be considered.
 ...
PMID:Lactic acidosis and acute ethanol intoxication. 828 68


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