Chloral hydrate enhances ethanol-induced inhibition of methanol oxidation in mice

Pentobarbital and other anesthetic agents induce opposite regulations of MAP kinases p-MEK and p-ERK, and upregulate p-FADD/FADD neuroplastic index in brain during hypnotic states in mice

Midazolam and ketamine-induced anesthesia were recently shown to induce a disruption of MEK/ERK sequential phosphorylation with parallel upregulation of p-FADD in the mouse brain. The present study was designed to assess whether other structurally diverse anesthetic agents (pentobarbital, ethanol, chloral hydrate, isoflurane) also impair brain p-MEK to p-ERK signal and increase p-FADD during the particular time course of 'sleep' in mice. Pentobarbital (50 mg/kg)-, ethanol (4000 mg/kg)-, chloral hydrate (400 mg/kg)-, and isoflurane (2% in O₂)-induced anesthesia (range: 24-60 min) were associated with unaltered or increased p-MEK1/2 (up to +155%) and decreased p-ERK1/2 (up to -60%) contents, revealing disruption of MEK to ERK activation in mouse brain cortex. These anesthetic agents also upregulated cortical p-FADD (up to +110%), but not total FADD (moderately decreased), which resulted in increased neuroplastic/survival p-FADD/FADD ratios (up to +2.8 fold). The inhibition of pentobarbital metabolism with SKF525-A (a cytochrome P450 inhibitor) augmented barbiturate anesthesia (2.6 times) and induced a greater and sustained upregulation of p-MEK with p-ERK downregulation, as well as prolonged increases of p-FADD content and p-FADD/FADD ratio (effects lasting for more than 240 min). Pentobarbital also upregulated significantly the cortical contents of other markers of neuroplasticity such as the ERK inhibitor p-PEA-15 (up to +46%), the transcription factor NF-κB (up to +27%) and the synaptic density protein PSD-95 (up to +20%) during 'sleep'. The results reveal a paradoxical stimulation of p-MEK without the concomitant (canonical) activation of p-ERK (e.g. with pentobarbital and isoflurane), for which various molecular mechanisms are discussed. The downregulation of brain p-ERK may participate in the manifestations of adverse effects displayed by most hypnotic/anesthetic agents in clinical use (e.g. amnesia).

The influence of L-carnitine on methanol biotransformation in rats

There persists a need for potent and safe inhibitors of alcohol dehydrogenase (ADH), to effectively treat methanol poisoning by slowing its rate of biotransformation to there toxic products, formaldehyde and formic acid. Only a few former papers have reported on the significant effectiveness of L-carnitine in treating ethanol poisoning as well as alcohol abuse. As are no reports on the effectiveness of L-carnitine in treating methanol poisoning till now, the current studies were conducted to investigate the influence of L-carnitine on both oxydative metabolism and elimination of methanol in rats. Male Sprague-Dawley rats, aged 3 months with the body weight of 200-230 g were divided into 6 groups at random, with two of the groups considered to be control. Rats were given drinking water (control) or methanol in two different doses of 3220 mg/kg b.m. or 6440 mg/kg b.m. intragastrically and 0.9% NaCl (control) or 6.2 mmol/kg b.m. of L-carnitine intraperitionelly. Within 96 hours after the administration of methanol and 0.9% NaCl or L-carnitine, the urine was collected and then the animals were decapitated. To determine methanol there were taken blood samples for clot, and to determine carnitine and its derivatives blood was taken into heparinized test tubes. During the autopsy liver was also secured. In all the experimental time points stated the methanol concentrations in blood, urine and liver homogenate were determined by a head-space gas chromatography.