• Energy Research
• Closed Access close
• Open Source close
• FR close
• Neuroscience close

AbstractActivation of potassium (K+) currents plays a critical role in the control of programmed cell death. Because pituitary adenylate cyclase‐activating polypeptide (PACAP) has been shown to inhibit the apoptotic cascade in the cerebellar cortex during development, we have investigated the effect of PACAP on K+ currents in cultured cerebellar granule cells using the patch‐clamp technique in the whole‐cell configuration. Two types of outward K+ currents, a transient K+ current (IA) and a delayed rectifier K+ current (IK) were characterized using two different voltage protocols and specific inhibitors of K+ channels. Application of PACAP induced a reversible reduction of the IK amplitude, but did not affect IA, while the PACAP‐related peptide vasoactive intestinal polypeptide had no effect on either types of K+ currents. Repeated applications of PACAP induced gradual attenuation of the electrophysiological response. In the presence of guanosine 5′‐[γthio]triphosphate (GTPγS), PACAP provoked a marked and irreversible IK depression, whereas cell dialysis with guanosine 5′‐[βthio]diphosphate GDPβS totally abolished the effect of PACAP. Pre‐treatment of the cells with pertussis toxin did not modify the effect of PACAP on IK. In contrast, cholera toxin suppressed the PACAP‐induced inhibition of IK. Exposure of granule cells to dibutyryl cyclic adenosine monophosphate (dbcAMP) mimicked the inhibitory effect of PACAP on IK. Addition of the specific protein kinase A inhibitor H89 in the patch pipette solution prevented the reduction of IK induced by both PACAP and dbcAMP. PACAP provoked a sustained increase of the resting membrane potential in cerebellar granule cells cultured either in high or low KCl‐containing medium, and this long‐term depolarizing effect of PACAP was mimicked by the IK specific blocker tetraethylammonium chloride (TEA). In addition, pre‐incubation of granule cells with TEA suppressed the effect of PACAP on resting membrane potential. TEA mimicked the neuroprotective effect of PACAP against ethanol‐induced apoptotic cell death, and the increase of caspase‐3 activity observed after exposure of granule cells to ethanol was also significantly inhibited by TEA. Taken together, the present results demonstrate that, in rat cerebellar granule cells, PACAP reduces the delayed outward rectifier K+ current by activating a type 1 PACAP (PAC1) receptor coupled to the adenylyl cyclase/protein kinase A pathway through a cholera toxin‐sensitive Gs protein. Our data also show that PACAP and TEA induce long‐term depolarization of the resting membrane potential, promote cell survival and inhibit caspase‐3 activity, suggesting that PACAP‐evoked inhibition of IK contributes to the anti‐apoptotic effect of the peptide on cerebellar granule cells.

Male mice of the BALB/c strain were given a solution of 15% ethanol as their only source of fluid for periods varying from 5 weeks to 8 months. For behavioral testing, they were compared with control groups which had received either an isocaloric solution of sucrose or tap water. Memory was tested by using spontaneous alternation behavior in a T maze. Each test consisted of two forced trials (acquisition) followed by a free trial (test) given at different acquisition--test intervals (from 30 s to 24 h). Results from two independent experiments showed that after 25 weeks of ethanol administration there was an accelerated rate of decay of spontaneous alternation as a function of the acquisition--test interval. Such a phenomenon persisted after ethanol was omitted from the diet. A third experiment showed that when tested on two successive sessions separated by a 5 h interval, experimental subjects exhibited a decreased ability to perform normally on the second test. Our data are interpreted as showing that long-term ethanol administration results in accelerated forgetting and increased vulnerability to proactive interference and, as such, they are compared to the memory dysfunctions observed in amnesic patients.

To investigate the efficacy of percutaneous chemonucleolysis using ethanol gel (PCEG) in alleviating radicular pain due to disc herniation after failure of conservative treatment.After failure of conservative treatment, PCEG was performed under fluoroscopic guidance in 42 patients with sciatica >4/10 on a Visual Analog Scale (VAS) for at least 6 weeks and consistent disc herniation on MRI or CT <3 months. The VAS pain score was determined at baseline, then after 1 and 3 months. We assessed the influence of patient-related factors (age, gender, pain duration) and disc herniation-related factors (level, migration pattern, disc herniation-related spinal stenosis) on outcome of PCEG.Mean pain duration was 6.7 months. Pain intensity decreased by 44% and 62.6% after 1 and 3 months, respectively, versus baseline (P = 0.007). A mild improvement was noted by the rheumatologist in 30/42 (71.4%) and 36/42 (85.7%) patients after 1 and 3 months, respectively, and in 31/42 (73.8%) and 33/42 (78.6%) patients by self-evaluation. Patients who failed PCEG were significantly older (49.8 vs. 37.3 years, P = 0.03). None of the other variables studied were significantly associated with pain relief.PCEG may significantly improve disc-related radicular pain refractory to conservative treatment.• Percutaneous chemonucleolysis using ethanol gel (PCEG) is feasible on an outpatient basis. • PCEG improves disc-related radicular pain refractory to conservative treatment. • PCEG is feasible on an outpatient basis. • Failure of PCEG does not interfere with subsequent spinal surgery.

In order to study the auditory effects of a metabolic interaction between ethanol and styrene, a first group of rats was gavaged once a day with ethanol (4 g/kg), a second group was exposed to 750 ppm styrene by inhalation, and a third group was exposed to both ethanol and styrene (5 days/week, 4 weeks). Auditory function was tested by recording brainstem (inferior colliculus) auditory evoked potentials, and cochlear hair cell loss was estimated by light microscopy. Cytochrome P450 2E1 and the main urinary styrene metabolites, namely mandelic, phenylglyoxylic and hippuric acids, were measured by high-performance liquid chromatography to check the effects of ethanol on styrene metabolism. In our experimental conditions, ethanol alone did not have any effect on auditory sensitivity, whereas styrene alone caused permanent threshold shifts and outer hair cell damage. Hearing and outer hair cell losses were larger after the exposure to both ethanol and styrene than those induced by styrene alone, indicating a clear potentiation of styrene ototoxicity by ethanol. As expected, metabolic data showed that ethanol alters styrene metabolism and can therefore be considered a modifying factor of styrene toxicokinetics.

To describe the long-term clinical and morphological outcome of symptomatic hepatic cysts treated with percutaneous ethanol sclerotherapy (PES).From December 2003 to September 2011, all patients with hepatic cysts undergoing PES with a follow-up after 12 months were included. Evolution of the volume of the cysts and clinical and biological data were recorded. Features of the cyst were evaluated in each patient: simple, haemorrhagic or developed on underlying polycystic liver disease (PCLD).Fifty-eight cysts (median volume 666 mL) were treated in 57 patients (52 women, mean age 58 years (18-80)). Twenty-two patients (39 %) had simple hepatic cysts, 19 (33 %) had dominant cysts on PCLD and 20 had haemorrhagic cysts (34.5 %), including 4 with PCLD. After a mean 27.3 months of follow-up, the final median cystic volume was 13.5 mL (p < 0.0001), and the median reduction in cyst volume was 94 % (58-100 %). Treatment was satisfactory in 95 % of the patients (54/57) (symptoms disappeared in 45/57 (79 %), decreased in 9/57 (16 %)). There was no clinical or morphological difference between patients with PCLD, haemorrhagic cysts or simple cysts.The clinical and morphological efficacy of a single session of PES is very high, regardless of the presence of intracystic haemorrhage or underlying PCLD.• The clinical efficacy of percutaneous ethanol sclerotherapy is very high. • Haemorrhagic content should not be a contraindication for percutaneous sclerotherapy. • Dominant cysts on polycystic liver disease should be treated with PES. • Imaging follow-up should not be performed shortly after the procedure.

Almost all of the important pathophysiological targets for ethanol in the nervous system appear to be specific membrane proteins involved in signal transduction. In this paper we have examined levels and functionality of the alpha subunit of the Go protein (Goalpha) in cerebral cortex and cerebellum from rats that have chronically ingested ethanol, by using immunoblotting and pertussis toxin-catalyzed ADP-ribosylation experiments. Goalpha protein levels were increased in plasma membranes from the two brain areas, and this increase was shown to specifically affect Go1alpha, one of the two isoforms of the Goalpha subunit. Results obtained here lead us to suggest that increased Go1alpha in plasma membranes would counteract a modified and non-functional protein generated during chronic alcohol treatment.

Convergent data showed that ethanol exposure during adolescence can alter durably ethanol-related behaviour at adulthood. However, the consequences of juvenile ethanol exposure on the reinforcing effects of other drugs of abuse remain unclear. In the present work, we evaluated in adult male DBA/2J mice the effects of early ethanol exposure on the sensitivity to the incentive effects of cocaine and morphine, and on extracellular signal-regulated kinase (ERK) activation in response to cocaine. Juvenile male mice received intragastric administration of ethanol (2×2.5g/kg/day) or water for 5 days starting on postnatal day 28. When reaching adult age (10 week-old), animals were subjected to an unbiased procedure to assess conditioned place preference (CPP) to cocaine or morphine. In addition, activation of ERK in response to an acute injection of cocaine was investigated using immunoblotting in the striatum and the nucleus accumbens. Mice that have been subjected to early ethanol exposure developed CPP to doses of cocaine (5mg/kg) or morphine (10mg/kg) below the threshold doses to induce CPP in water pre-exposed mice. In addition, early ethanol administration significantly increased striatal ERK phosphorylation normally induced by acute cocaine (10 and 20mg/kg) in adult mice. These results show that, in DBA/2J mice, early exposure to ethanol enhanced the perception of the incentive effects of cocaine and morphine. Ethanol pre-exposure also induced a positive modulation of striatal ERK signalling, in line with the inference that juvenile ethanol intake may contribute to the development of addictive behaviour at adult age.

Rats were chronically intoxicated with alcohol by exposing them to increasing concentrations of ethanol vapor over a 4‐week period. They were tested for alcohol consumption in a free choice situation of water and 10% (v/v) alcohol. On the basis of their intakes they were divided into alcohol‐dependent and nondependent groups. Synaptosome membrane fluidity evaluated by fluorescence polarization was compared between the two groups and against nonintoxicated controls. The intoxicated animals had a lower membrane fluidity than controls, mainly because of a highly significant increase of rigidity in the alcohol‐dependent group. Furthermore, membrane fluidity was found to be correlated with the degree of behavioral dependence (i.e., alcohol intake during the free choice period).

The purpose of this study was to further address the hypothesis that ethanol activates GABAergic neurons in specific brain neurocircuits that mediate motivated behavior and control of action, such as the central extended amygdala and medial prefrontal cortex. Male Sprague-Dawley rats received habituation to 7 days of daily intragastric administration of water (5 ml/kg) followed by a single acute intragastric dose of ethanol (2.5 g/kg) or water then, 2 h later, by paraformaldehyde perfusion. Rats left undisturbed in the animal room throughout the experiment were also perfused (naive group). Brain sections were processed for single Fos immunohistochemistry or dual Fos immunohistochemistry/glutamic acid decarboxylase (GAD) mRNA in situ hybridization. Intragastric water administration increased the number of Fos-immunoreactive cells in the infralimbic cortex and lateral part of the central nucleus of the amygdala compared with the naive group. Ethanol administration increased the number of Fos-immunoreactive cells in the infralimbic (+57.5%) and prelimbic (+105.3%) cortices, nucleus accumbens shell region (+88.2%), medial part of the central nucleus of the amygdala (+160%), and lateral part of the bed nucleus of the stria terminalis (+198.8%) compared with the water-treated group. In the nucleus accumbens shell region, central nucleus of the amygdala, and bed nucleus of the stria terminalis, more than 80% of Fos-immunoreactive neurons were GABAergic after ethanol administration. In contrast, in the prelimbic cortex, 75% of Fos-immunoreactive neurons were not GABAergic. These results constitute new evidence for region-specific functional interactions between ethanol and GABAergic neurons.