Central nervous system prostaglandins and ethanol

The Inflammatory Signals Associated with Psychosis: Impact of Comorbid Drug Abuse

Psychosis and substance use disorders are two diagnostic categories whose association has been studied for decades. In addition, both psychosis spectrum disorders and drug abuse have recently been linked to multiple pro-inflammatory changes in the central nervous system. We have carried out a narrative review of the literature through a holistic approach. We used PubMed as our search engine. We included in the review all relevant studies looking at pro-inflammatory changes in psychotic disorders and substance use disorders. We found that there are multiple studies that relate various pro-inflammatory lipids and proteins with psychosis and substance use disorders, with an overlap between the two. The main findings involve inflammatory mediators such as cytokines, chemokines, endocannabinoids, eicosanoids, lysophospholipds and/or bacterial products. Many of these findings are present in different phases of psychosis and in substance use disorders such as cannabis, cocaine, methamphetamines, alcohol and nicotine. Psychosis and substance use disorders may have a common origin in an abnormal neurodevelopment caused, among other factors, by a neuroinflammatory process. A possible convergent pathway is that which interrelates the transcriptional factors NFκB and PPARγ. This may have future clinical implications.

Alcohol abuse promotes changes in non-synaptic epileptiform activity with concomitant expression changes in cotransporters and glial cells

Non-synaptic mechanisms are being considered the common factor of brain damage in status epilepticus and alcohol intoxication. The present work reports the influence of the chronic use of ethanol on epileptic processes sustained by non-synaptic mechanisms. Adult male Wistar rats administered with ethanol (1, 2 e 3 g/kg/d) during 28 days were compared with Control. Non-synaptic epileptiform activities (NEAs) were induced by means of the zero-calcium and high-potassium model using hippocampal slices. The observed involvement of the dentate gyrus (DG) on the neurodegeneration promoted by ethanol motivated the monitoring of the electrophysiological activity in this region. The DG regions were analyzed for the presence of NKCC1, KCC2, GFAP and CD11b immunoreactivity and cell density. The treated groups showed extracellular potential measured at the granular layer with increased DC shift and population spikes (PS), which was remarkable for the group E1. The latencies to the NEAs onset were more prominent also for the treated groups, being correlated with the neuronal loss. In line with these findings were the predispositions of the treated slices for neuronal edema after NEAs induction, suggesting that restrict inter-cell space counteracts the neuronal loss and subsists the hyper-synchronism. The significant increase of the expressions of NKCC1 and CD11b for the treated groups confirms the existence of conditions favorable to the observed edematous necrosis. The data suggest that the ethanol consumption promotes changes on the non-synaptic mechanisms modulating the NEAs. For the lower ethanol dosage the neurophysiological changes were more effective suggesting to be due to the less intense neurodegenertation.

Effect of ethanol on the release of prostaglandins from ovine fetal brain stem during gestation

Prostaglandins (PGs) have been implicated as mediators of the ethanol-induced suppression of ovine fetal breathing movements (FBM). The objectives of the present study were to determine the ontogeny of the in vitro efflux of PGE2 and 6-keto PGF1 alpha in ovine fetal brain stem during the second half of gestation and to determine the effect of in vitro ethanol exposure on the efflux of these PGs. Ovine fetal brain stem tissue was obtained at mean gestational ages of 80 days (n = 6), 105 days (n = 10), and 135 days (n = 16) by rapid excision following maternal euthanization. Tissue slices (400 microM thickness) were prepared from the lower pons-medulla region of the brain stem. After a 1-hr equilibration period in artificial cerebrospinal fluid, efflux of PGE2 and 6-keto PGF1 alpha in the brain stem was determined using the brain slice-superfusion method, and the PGE2 and 6-keto PGF1 alpha concentrations in the superfusate were determined by specific radioimmunoassay. The mean spontaneous efflux of PGE2 and 6-keto PGF1 alpha expressed as pmol PG/gram wet weight of tissue/5-min collection period was, respectively, 31.9 +/- 4.2 and 26.6 +/- 2.4 at 80 days, 38.3 +/- 5.2 and 29.6 +/- 2.2 at 105 days, and 57.4 +/- 3.1 and 27.1 +/- 1.1 at 135 days of gestation. In vitro exposure to 20, 40, and 80 mM ethanol did not affect PG efflux in the brain stem at 80 and 105 days of gestation. In vitro ethanol exposure decreased PGE2 and 6-keto PGF1 alpha efflux at 135 days of gestation to 36.8 +/- 5.3% and 41.6 +/- 4.3% of spontaneous efflux within 15 min, respectively; this effect of ethanol was not dose-dependent. The data do not support the hypothesis that ethanol increases PG efflux in the ovine fetal brain stem. In view of these findings and the data implicating PGs in the mechanism of ethanol-induced suppression of FBM, it is possible that ethanol acts at either central sites rostral to the brain stem (i.e., upstream CSF) or peripheral sites to increase the synthesis of PGs and their efflux into the systemic circulation, with subsequent transfer to the respiratory control region(s) of the brain stem.

Effects of indomethacin, aspirin, and acetaminophen on ethanol diuresis in rats

A number of studies have indicated that prostaglandin synthetase inhibitors (PGSI) can antagonize several effects of ethanol. This study examines the influence of intraperitoneal pretreatment with the PGSI indomethacin (5.0 or 10.0 mg/kg), aspirin (15.0 or 30.0 mg/kg) and acetaminophen (15.0 or 30.0 mg/kg) on the diuretic effect produced by orally administered ethanol (4.0 g/kg) in female rats. Pretreatments with indomethacin and aspirin led to an antagonism of ethanol's diuretic effect. Nevertheless, acetaminophen failed to antagonize this effect. These results are in agreement with data from the literature on PGSI versus ethanol and suggest possible involvement of prostaglandins in the diuretic effect of ethanol.

The effects of alcoholism and smoking on platelet eicosanoid production in vitro

Ethanol induces changes in eicosanoid synthesis in blood platelets and brain tissue. Cigarette smoking also causes alterations in eicosanoid formation. This preliminary report examined in vitro platelet sonicate eicosanoid production using 14C-arachidonic acid (14C-AA) and in separate experiments, 14C-PGH2, as substrates. Radiometric thin layer chromatography (TLC) was used to identify the products formed. Eicosanoid product formation in platelet sonicates collected from 28 abstinent male alcoholics were compared to those from 11 male control subjects. All but one of the alcoholics were chronic smokers and all control subjects were non-smokers. All smokers abstained from smoking for 12 h prior to the blood collection to control for any acute effects of cigarette smoke on eicosanoid production. Significant reductions in platelet sonicate production of PGD2 and PGE2 in vitro were observed in alcoholic smokers when 14C-PGH2, but not 14C-AA, was the substrate. These reductions were predicted equally well by two variables, smoking and alcoholism, using several statistical models. This is the first investigation that controlled for the acute effects of smoking and accounted for the potential effects of cigarette smoking on platelet eicosanoid production in alcoholics. Because cigarette smoking is prevalent among alcoholics, future studies on the role of eicosanoids in alcoholism should control for smoking.

Prostaglandin E2 reduces voluntary ethanol consumption in the rat

A number of prior studies have suggested that the prostaglandins may mediate some of the physiological effects of ethanol, and while it has been suggested that PGE2 may be involved in regulating ethanol consumption, evidence for this has been inconclusive. In the present study, rats injected with PGE2 at doses of 50, 100 and 200 micrograms/kg consumed significantly less alcohol than vehicle-treated controls. Doses of PGE2 which were highly effective in reducing ethanol intake produced only marginal changes in the consumption of water and glucose solution. These data, together with previous studies demonstrating a link between ethanol and the prostaglandins, suggest that PGE2 may be involved in the control of ethanol consumption.

Ethanol increases PGE and thromboxane production in mouse pregnant uterine tissue

The teratogenic effect of ethanol in the C57BL/6J mouse can be attenuated by pretreatment with aspirin (ASA). One prominent effect of ASA is to inhibit prostaglandin (PGE) and thromboxane (TXB2) production. We examined the effect of in vivo ethanol exposure on PGE and TXB2 production in a uterine-embryo tissue sample of C57BL/6J mice either before or after in vivo ASA pretreatment on day 10 of gestation. Ethanol increased both PGE and TXB2 production by approximately 20%. ASA caused a marked reduction of PGE and TXB2 in both control and ethanol groups by approximately 80-90%. The mouse strain, gestation time, and study parameters used in this study were the same as in the previously reported ASA attenuation of the teratogenic effect of ethanol. Therefore, the present data add additional support to the hypothesis that prostaglandin and/or thromboxane production may be involved in at least some aspects of fetal alcohol syndrome.

Prostaglandins in cerebrospinal fluid of healthy human volunteers, abstinent alcoholics and rhesus monkeys

A sensitive and selective assay for measuring prostaglandins in cerebrospinal fluid has been developed, based on the selected-ion-monitoring, electron-capture negative ionization GC/MS detection for the MO-PFB-TMS derivatives of prostaglandins E2, E1, F2 alpha, F1 alpha, and 6-keto-F1 alpha. Improvements over previously published assay procedures have been made, and the new assay has been applied to measurement of prostaglandin concentrations in lumbar CSF of healthy human volunteers, abstinent alcoholic patients, in cisternal CSF of Rhesus monkeys, and continuously sampled lumbar CSF of awake Rhesus monkeys. Results indicated that the concentrations of PGE2, PGE1, PGF1 alpha, and 6-keto-PGF1 alpha were below 15 pg/mL CSF in lumbar CSF of healthy humans and abstinent alcoholics, and in cisternal CSF of Rhesus monkeys. In contrast, continuously sampled lumbar CSF of awake Rhesus monkeys contained more than 200 pg/mL of PGE2, PGF2 alpha, and 6-keto-PGF1 alpha, probably present as a result of local production.

Aspirin augments alcohol in restricting brain growth in the neonatal rat

The purpose of this study was to determine whether the microencephaly in rats resulting from early postnatal alcohol exposure is altered by a concurrent administration of aspirin. Neonatal rats were artificially reared from postnatal day 4 to postnatal day 10, a period of the brain growth spurt in the rat that is similar to the third trimester of human brain development. The alcohol-treated groups received 6.6 g/kg/day of ethanol and either 0.0, 12.5, 25.0 or 50.0 mg/kg/day of aspirin in a milk solution. Control groups received either 0.0 (gastrostomy control), 12.5, 25.0 or 50.0 mg/kg/day of aspirin in a milk solution free of alcohol. Brainstem, cerebellum and total brain weights were measured on postnatal day 10. Alcohol alone significantly reduced the mean total brain weight, cerebellum and brainstem weight by 19.8%, 23.1% and 12.2%, respectively, relative to gastrostomy controls. A significant interaction between ethanol and aspirin was observed for total brain weight. The mean total brain weight of the group receiving both alcohol and 50 mg/kg/day aspirin was significantly lower than all other experimental groups and was reduced 29.5%, relative to gastrostomy controls. The highest dose of aspirin alone significantly reduced cerebellar weight, relative to gastrostomy controls but had no effect on brainstem or total brain weight.

PGE measurement in mouse embryos and uterine/embryo tissue

Embryonic tissue of rodents and other species has been reported to produce prostaglandins (PG) of the E series during gestation. We attempted to establish the presence of PGE in C57BL/6J mouse embryos and peri-embryonic tissue as an initial step in examining the role of maternal ethanol treatment on PG production. Gestation day 10 embryos were found not to produce or degrade PGE. However, a tissue complex which included embryonic tissue, peri-embryonic membranes, placenta and uterus was capable of producing PGE from both endogenous and exogenous arachidonic acid. Furthermore, in vivo and in vitro aspirin was able to suppress PGE production from this tissue. It is concluded that gestation day 10 C57BL/6J mouse embryonic tissue, unlike that of rat, is not capable of measurable PGE production. However, uterine and peri-embryonic tissues, needed to support pregnancy, are capable of significant PGE production.

Acute ethanol poisoning and the ethanol withdrawal syndrome

Ethanol, a highly lipid-soluble compound, appears to exert its effects through interactions with the cell membrane. Cell membrane alterations indirectly affect the functioning of membrane-associated proteins, which function as channels, carriers, enzymes and receptors. For example, studies suggest that ethanol exerts an effect upon the gamma-aminobutyric acid (GABA)-benzodiazepine-chloride ionophore receptor complex, thereby accounting for the biochemical and clinical similarities between ethanol, benzodiazepines and barbiturates. The patient with acute ethanol poisoning may present with symptoms ranging from slurred speech, ataxia and incoordination to coma, potentially resulting in respiratory depression and death. At blood alcohol concentrations of greater than 250 mg% (250 mg% = 250 mg/dl = 2.5 g/L = 0.250%), the patient is usually at risk of coma. Children and alcohol-naive adults may experience severe toxicity at blood alcohol concentrations less than 100 mg%, whereas alcoholics may demonstrate significant impairment only at concentrations greater than 300 mg%. Upon presentation of a patient suspected of acute ethanol poisoning, cardiovascular and respiratory stabilisation should be assured. Thiamine (vitamin B1) and then dextrose should be administered, and the blood alcohol concentration measured. Subsequent to stabilisation, alternative aetiologies for the signs and symptoms observed should be considered. There are presently no agents available for clinical use that will reverse the acute effects of ethanol. Treatment consists of supportive care and close observation until the blood alcohol concentration decreases to a non-toxic level. In the non-dependent adult, ethanol is metabolised at the rate of approximately 15 mg%/hour. Haemodialysis may be considered in cases of a severely ill child or comatose adult. Follow-up may include referral for counselling for alcohol abuse, suicide attempts, or parental neglect (in children). The ethanol withdrawal syndrome may be observed in the ethanol-dependent patient within 8 hours of the last drink, with blood alcohol concentrations in excess of 200 mg%. Symptoms consist of tremor, nausea and vomiting, increased blood pressure and heart rate, paroxysmal sweats, depression, and anxiety. Alterations in the GABA-benzodiazepine-chloride receptor complex, noradrenergic overactivity, and hypothalamic-pituitary-adrenal axis stimulation are suggested explanations for withdrawal symptomatology.(ABSTRACT TRUNCATED AT 400 WORDS)