Biomedical subjects

C Alling

Publications and source records attributed to C Alling.

At least 55 records · Page 3Linked to original sources

PubMed1995

Ethanol inhibits the peak of muscarinic receptor-stimulated formation of inositol 1,4,5-trisphosphate in neuroblastoma SH-SY5Y cells.

The effect of ethanol on muscarinic receptor-stimulated formation of inositol 1,4,5-trisphosphate was studied in human neuroblastoma SH-SY5Y cells. Stimulation with carbachol induced a biphasic increase of inositol 1,4,5-triphosphate with an initial peak after 10 sec declining to a plateau phase of elevation above basal levels, which was sustained for at least 5 min in the presence of agonist. The peak, but not the plateau phase, was concentration-dependently decreased by exposure to ethanol. Maximal inhibition was obtained within 30 sec of exposure to ethanol. Ethanol caused an increase in the EC50 value of carbachol for the initial rate of inositol 1,4,5-trisphosphate formation, measured after 10 sec of stimulation, from 98 microM in the absence to 196 microM in the presence of 100 mM ethanol. The potencies of pirenzepine and hexahydro-sila-difenidol hydrochloride for inhibiting [3H]quinuclidinyl benzilate binding and inositol 1,4,5-trisphosphate formation suggest that both phases are mediated via the muscarinic M1 receptor. Phorbol 12-myristate 13-acetate inhibited both phases of inositol 1,4,5-trisphosphate formation, whereas okadaic acid and modulators of cAMP-dependent protein kinase were without any effect. There was no inhibitory effect of ethanol when protein kinase C was inhibited by H7 and calphostin C, indicating that the ethanol effect is dependent on protein kinase C activity.

Carbachol↗

PubMed1995

Calmidazolium inhibits muscarinic receptor-mediated PLC activation in SH-SY5Y cells.

The aim of this study was to investigate the effect of a calmodulin antagonist, calmidazolium, on the muscarinic receptor-mediated increase in inositol 1,4,5-trisphosphate [I(1,4,5)P3] in SH-SY5Y cells. Exposure to 10 microM calmidazolium suppressed the initial I(1,4,5)P3 peak increase (IC50 1 microM) whereas the steady-state was less affected. Furthermore, calmidazolium displayed non-competitive antagonistic properties of [3H]quinuclidinyl benzylate binding to intact SH-SY5Y cells and to membranes from these cells. These effects were also obtained with another calmodulin inhibitor, trifluoperazine (10 microM). These results demonstrate that novel finding that the calmodulin inhibitors calmidazolium and trifluoperazine act as non-competitive muscarinic antagonists in SH-SY5Y cells and inhibit muscarinic receptor-stimulated phospholipase C activation in these cells.

Animals↗

PubMed1995

Cerebral complications after cardiac surgery assessed by S-100 and NSE levels in blood.

OBJECTIVE: Assessment of the value of blood analysis of the astroglia protein, S-100, and neuron-specific enolase for the detection of nervous system dysfunction after cardiac surgery. DESIGN: Prospective study. Neurologists blinded from laboratory results. SETTING: University hospital. PARTICIPANTS: 38 patients undergoing cardiac surgery. INTERVENTIONS: 21 patients were operated for coronary artery disease; seven patients with replacement of the aortic valve of whom 2 also had coronary bypass. Four patients had mitral valve replacement of whom 2 also had coronary bypass. One patient had both aortic and mitral valve replacement and coronary bypass. Two patients were operated on because of aortic arch aneurysm. MEASUREMENTS AND MAIN RESULTS: Neurologic examinations were performed before and after surgery. General behavior of the patients was repeatedly assessed. Blood samples for analysis were collected before operation and on the second day after surgery. In 8/38 patients (21%), a neurologic complication, one of which was lethal, occurred. In 27 patients (71%), the neurologic outcome was uncomplicated, and in 3 (8%), it could not be classified. Elevated S-100 and neuron-specific enolase levels were found in 7/8 patients who endured a neurologic complication and in 4/27 free of complication. (Fisher's exact test p < 0.001). Positive and negative predictive values were 64% and 96%, respectively. S-100 (range 0.5 to 1.3 micrograms/L) and neuron-specific enolase levels (range 8.6 to 16.7 micrograms/L) were lower for the 7 patients with nonlethal complications than for the patient who died (9.5 micrograms/L and 31.3 micrograms/L, respectively). CONCLUSIONS: S-100 and neuron-specific enolase levels after cardiac surgery are associated with neurologic complications. The results have implications on patient-related treatment and prognosis as well as for the development of safer perfusion techniques.

Aged↗

PubMed1995

Increases and time-course variations in beta-hexosaminidase isoenzyme B and carbohydrate-deficient transferrin in serum from alcoholics are similar.

beta-Hexosaminidase B-isoforms (beta-hexosaminidase B, P, and intermediate forms; abbreviated herein as "Hex B") and serum carbohydrate-deficient transferrin (CDT) are two markers of alcohol abuse. In the present study, we have compared "Hex B" with CDT as markers of alcohol abuse in a group of alcoholics hospitalized for detoxification after a period of heavy alcohol abuse. We have also followed the disappearance rate of these two markers from circulation. "Hex B" was elevated in 38 of 42 patients hospitalized for detoxication, whereas CDT was elevated in 35 of 42 patients. A highly significant correlation was noted between "Hex B" and CDT in these patients (p = 0.52, p < 0.001). Neither "Hex B" nor CDT correlated with gamma-glutamyltransferase or AST. The disappearance rates from serum of "Hex B" and CDT were determined in 21 hospitalized patients followed for up to 15 days. "Hex B" and CDT showed similar time-course variation and half-lives, 6.5 +/- 3.7 (mean +/- SD) and 8.6 +/- 4.1 days, respectively. The possible reasons for a relation between these two markers are discussed, and it is concluded that more experience of both "Hex B" and CDT in unselected populations is needed to establish the diagnostic potential of these tests as markers of alcohol abuse.

Adult↗

PubMed1995

Intermittent ethanol exposure of adult rats: hippocampal cell loss after one month of treatment.

The effects of intermittent intraperitoneal ethanol exposure (3 g/kg body weight twice daily) on hippocampal cells of adult rats were examined after a 1-month exposure period. Continuous oral exposure to ethanol in the drinking water (20%) over the same time period was used for comparison. Pyramidal cells from the CA3 region and granule cells from the dentate gyrus were also qualitatively assessed using electron microscopy. One month of intermittent, peaking, exposure induced a significant loss of CA2-CA3 pyramidal cells and an increase in the number of lipofuscin granules in the remaining cells. A significant reduction in thickness of the dentate gyrus granule cell layer was also seen in the same animals. No significant reduction in pyramidal cell number or granule cell layer thickness was seen in continuously orally exposed animals in spite of a higher total ethanol intake. These studies thus demonstrate the harmful effect of intermittent high ethanol peaks and repeated withdrawal phases on hippocampal cells of the mammalian brain and emphasize the importance of considering the differential effects of different ethanol exposure patterns when assessing ethanol-induced cellular damage.

Administration, Oral↗

PubMed1994

Protein kinase C-mediated phospholipase D activity is increased by linolenic acid supplementation in NG 108-15 cells.

Phospholipase D activation was studied in NG 108-15 cells after manipulation of the phospholipid fatty acid composition. Cultivation of cells in media containing different polyunsaturated fatty acids induced extensive and specific changes in the phospholipid fatty acid composition. General for all phospholipids was an increase in polyunsaturated fatty acids at the expense of monounsaturated fatty acids. To examine phospholipase D activation, cells were stimulated with phorbol esters in the presence of ethanol and the formation of phosphatidylethanol was analyzed. In cells cultured with linolenic acid, a significantly higher amount of phosphatidylethanol was formed compared to control cells. On the other hand, supplementation with linoleic, arachidonic or docosahexaenoic acids did not induce any changes in phospholipase D activity. The effect was not due to free fatty acids in the cell culture medium and thus probably induced by fatty acids incorporated into membrane phospholipids or fatty acid metabolites. The results indicate a specific effect of linolenic acid and/or its metabolites on protein kinase C-mediated phospholipase D activity.

Cell Line↗

PubMed1994

Phosphatidylethanol formation and degradation in brains of acutely and repeatedly ethanol-treated rats.

The formation of the abnormal phospholipid phosphatidylethanol (PEth) was studied in hippocampus, cerebellum and cerebrum of rat brain after intraperitoneal ethanol administration. Prior to analysis by high performance thin layer chromatography PEth was purified. After one injection, PEth levels reached a maximum after 2 h and remained detectable for 14-24 h in all three regions. Repeated injections led to additional accumulation. Maximum in vivo levels of 30-50 nmol/g wet wt. were reached.

Animals↗

PubMed1994

Mechanisms of muscarinic receptor-stimulated expression of c-fos in SH-SY5Y cells.

In this study, the signal cascade transducing carbachol stimulation into c-fos expression in SH-SY5Y neuroblastoma cells was investigated. 1,2-Diacylglycerol formation and c-fos expression were mediated via stimulation of muscarinic M1 receptors and the first 5 min of receptor stimulation were critical for these events. Application of 1,2-dioctanoylglycerol induced c-fos expression and this, as well as carbachol-stimulated c-fos expression, was inhibited by protein kinase C inhibitors. Increasing the intracellular Ca2+ concentration had only small effects on c-fos expression. There was a dependency on extracellular Ca2+ for maximal c-fos expression and 1,2-diacylglycerol formation. The carbachol-stimulated c-fos expression was potentiated by application of the protein phosphatase inhibitor okadaic acid. These results demonstrate the importance of 1,2-diacylglycerol formation for muscarinic receptor-stimulated, protein kinase C-mediated c-fos expression in the SH-SY5Y cells and that this cascade is counteracted by an okadaic acid-sensitive protein phosphatase.

Carbachol↗

PubMed1994

Adaptation of signal transduction in brain.

Cell culture models were used to study the effects of long-term ethanol exposure on neuronal cells. Effects on phospholipase C and phospholipase D mediated signal transduction were investigated by assaying receptor-binding, G protein function, activities of lipases, formation of second messengers and c-fos mRNA. The signal transduction cascades displayed abnormal activities from 2 to 7 days of exposure which differed from the acute effects. Phosphatidylethanol formed by phospholipase D is an abnormal lipid that may harmfully affect nerve cell function.

Acclimatization↗

PubMed1994

Long-term effects of intermittent versus continuous ethanol exposure on hippocampal synapses of the rat.

The hippocampus is known to be very sensitive to a large spectrum of different neurotoxins including ethanol. Ethanol administered continuously or intermittently may affect the hippocampus in different ways. Intermittent administration of ethanol has many features in common with the low level electrical stimulation protocols which lead to the functional changes associated with the phenomenon of kindling. In this study, the differential effects of intermittent intraperitoneal ethanol injections (3 g/kg twice daily) and continuously administered ethanol in drinking water (20%) on hippocampal synapses in the rat were studied using ethanolic phosphotungstic acid staining and electron microscopy. After 1 month of intermittent exposure a significant reduction (18%) of synapses was seen in the stratum lucidum of the CA3 region. Continuously treated animals showed no significant change over this time despite a higher total ethanol intake. In the dentate gyrus, a compensatory increase in supragranular synaptic number was seen only in continuously treated animals. These findings demonstrate the sensitivity of synapses of the hippocampus to the presence of ethanol and the larger effects of peaking ethanol concentrations compared to more constant levels. These results emphasize the need to consider the differential effects of various types of ethanol consumption also on the human brain.

Animals↗

PubMed1994

The effect of paroxetine on cerebrospinal fluid concentrations of neurotransmitter metabolites in depressed patients.

This paper describes the effect of the selective serotonin reuptake inhibiting drug (SSRI), paroxetine, on cerebrospinal fluid concentrations of neurotransmitter metabolites in depressed patients. 5-Hydroxyindoleacetic acid (5-HIAA), 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) were measured at baseline and after 3 weeks of treatment with 30 mg paroxetine daily. In line with similar studies on other SSRIs, influence on both the serotonin and noradrenaline metabolite was found. The mechanism behind the action of paroxetine on both 5-HIAA and MHPG is assumed to be an expression of the linkage between the serotonergic and noradrenergic systems in the brain. A frequently reported correlation between 5-HIAA and HVA was also found. The analysis of paroxetine in CSF proves the transportation of the drug into the central nervous system.

Aged↗

PubMed1994

Cerebrospinal fluid levels of monoamine metabolites. A preliminary study of their relation to menstrual cycle phase, sex steroids, and pituitary hormones in healthy women and in women with premenstrual syndrome.

The cerebrospinal fluid (CSF) levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), the noradrenaline metabolite 3-methoxy-4-hydroxyphenylethylene glycol (MHPG), and the dopamine metabolite homovanillic acid (HVA) were measured in a group of drug-free non-depressed women with premenstrual syndrome (PMS) (late luteal phase dysphoric disorder) (n = 13) and in controls with no premenstrual complaints (n = 13). In six patients and eight controls, CSF samples from both the luteal and the follicular phase were obtained, whereas in the remainder of the subjects, samples from either the follicular phase (patients: 4, controls: 2) or the luteal phase (patients: 3, controls: 3) were taken. The following observations were made: (1) Neither in the follicular phase nor in the luteal phase did the mean concentrations of CSF monoamine metabolites in the PMS group differ from the corresponding values in the control group. (2) Neither in the PMS group nor in the control group did the mean concentrations of monoamine metabolites in CSF samples obtained in the luteal phase differ from the corresponding values obtained in the follicular phase. (3) The intraindividual, intersample variations of CSF HVA and 5-HIAA concentrations were significantly smaller in the PMS group than in the control group. (4) CSF HVA correlated strongly to CSF 5-HIAA in the luteal phase of both patients and controls whereas in the follicular phase, particularly in controls, this correlation was much weaker. (5) In the luteal phase, the CSF HVA/5-HIAA ratio correlated negatively to serum levels of estradiol, progesterone, and testosterone. (6) The CSF HVA/5-HIAA ratio was significantly lower in PMS patients than in controls. (7) A positive correlation between CSF MHPG and serum luteinizing hormone was observed in the follicular phase. (8) A positive correlation between CSF HVA and serum prolactin was observed in the luteal phase. Because the study was comprised of a small number of subjects, the reported findings until replicated should be interpreted with caution.

Adult↗

PubMed1994

Agonist-stimulated and basal phosphatidylethanol formation in neutrophils from alcoholics.

Phospholipase D has been shown to be a key enzyme in the signal transduction systems involved in neutrophil activation. In the presence of ethanol, the enzyme catalyzes a transphosphatidylation reaction through which phosphatidylethanol is formed instead of the normal product phosphatidic acid. The effects of ethanol on the formation of phosphatidylethanol and phosphatidic acid was studied in neutrophils from human alcoholics in vitro. Neutrophils were isolated and cellular lipids were labeled with [3H]oleate, whereafter the cells were preincubated with cytochalasin B. Subsequently, cells were stimulated with the chemotactic peptide formyl-Met-Leu-Phe in the presence of ethanol concentration ranging from 0 to 200 mM. In the presence of ethanol, both neutrophils from alcoholics and controls produced phosphatidylethanol, with a concomitant reduction of the production of phosphatidic acid. The amounts of phosphatidyl-ethanol and phosphatidic acid formed were dependent on the concentration of ethanol. In neutrophils from alcoholics, a higher apparent Km for the phospholipase D-mediated transphosphatidylation reaction was noted (58 mM ethanol compared with 28 mM in controls). The in vivo mass of phosphatidylethanol in recently drinking alcoholics was also analyzed in neutrophils. Measurable phosphatidyl-ethanol levels (average 5.6 pmol/10(8) neutrophils) were found in alcoholics up to 23 hr after the last intake of ethanol. Thus, in addition to the ethanol-induced changes in the normal production of phosphatidic acid, phosphatidylethanol accumulated in vivo in alcoholics may be expected to influence neutrophil function.

Adult↗

PubMed1994

Muscarinic receptor-stimulated expression of c-fos in neuroblastoma cells.

The intracellular signal cascade transducing muscarinic-receptor-stimulation to gene expression was investigated in human neuroblastoma SH-SY5Y cells. Naive and ethanol-exposed SH-SU5Y cells were stimulated with carbachol (CCh) and inositol 1,4-5-trisphosphate (IP3), 1,2-diacylglycerol (DAG), and c-fos mRNA levels were analyzed using a radioreceptor assay (IP3) thin-layer chromatography (DAG) and Northern blot (c-fos mRNA). Application of the muscarinic agonist CCh induced a rapid increase in (IP3), peaking within seconds after the CCh-addition. There was also an accumulation of DAG reaching maximum after 5 min of receptor-stimulation. Stimulation with CCh also induced expression of the immediate-early gene c-fos in these cells. These events were mediated via muscarinic M1 receptors and the inhibitory effects of H7, staurosporin, and RO31-7549 on the c-fos expression indicated that it was mediated via protein kinase C. Acute exposure to 100 mM ethanol inhibited the formation of IP3 and the expression of c-fos. These effects were due to an increase in the EC50 of CCh for the events. Exposure to 100 mM ethanol for 4 days caused a potentiation of these two events. The EC50 was unaffected but the maximal response was increased. These data indicate that this signal transduction system is inhibited by acute exposure to 100 mM ethanol, an effect that is compensated for after exposure to ethanol for 4 days.

Carbachol↗

PubMed1993

An okadaic acid-sensitive protein phosphatase counteracts protein kinase C-induced phosphorylation in SH-SY5Y cells.

Protein phosphorylation and subsequent dephosphorylation was studied in digitonin-permeabilized neuroblastoma SH-SY5Y cells by measuring the incorporation of [32P]phosphate into myelin basic protein (MBP). 1,2-Dioctanoyl-sn-glycerol (DOG) and calcium synergistically induced phosphorylation of MBP, which was inhibited by the protein kinase C (PKC) pseudosubstrate peptide (PKC19-36). The phosphorylation increased for 10 min when a net dephosphorylation started to appear. The dephosphorylation was inhibited by okadaic acid. Regardless of calcium concentration, the presence of DOG was necessary for significant effects of okadaic acid on MBP phosphorylation. H7 and staurosporine dose-dependently inhibited the phosphorylation of MBP, induced by DOG and calcium in the presence of okadaic acid. Different PKC pseudosubstrate peptides were applied and all showed an inhibitory effect on the phosphorylation of MBP under these conditions. These results demonstrate the presence, in SH-SY5Y cells, of a protein phosphatase, possibly protein phosphatase 2A, with a high basal activity that counteracts PKC-induced phosphorylation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1993

Phosphatidylethanol affects inositol 1,4,5-trisphosphate levels in NG108-15 neuroblastoma x glioma hybrid cells.

Phosphatidylethanol is formed by phospholipase D in animal cells exposed to ethanol. Previous reports have demonstrated that the degradation of phosphatidylethanol is slow, indicating that this lipid may be present in the cells after ethanol itself has disappeared. Accumulation of an abnormal alcohol metabolite may influence cellular functions. In the present study, cultivation of NG108-15 neuroblastoma x glioma hybrid cells in the presence of ethanol resulted in an accumulation of phosphatidylethanol and a simultaneous increase in basal inositol 1,4,5-trisphosphate levels. The direct effects of phosphatidylethanol on the phosphoinositide signal transduction system were examined through incorporation of exogenous phosphatidylethanol into membranes of ethanol-naive cells. An incorporation amounting to 2.8% of cellular phospholipids was achieved after a 5-h incubation with 30 microM phosphatidylethanol. Phosphatidylethanol was found to cause a time- and dose-dependent increase in the basal levels of inositol 1,4,5-trisphosphate. The effects on inositol 1,4,5-trisphosphate levels of exogenously added phosphatidylethanol and ethanol exposure for 2 days were not additive. No effect on bradykinin-stimulated inositol 1,4,5-trisphosphate production could be detected. However, the increase in basal inositol 1,4,5-trisphosphate levels indicates that phosphatidylethanol affects inositol 1,4,5-trisphosphate turnover and emphasizes the importance of considering phosphatidylethanol as a possible mediator of ethanol-induced effects on cellular processes.

Animals↗

PubMed1993

The role of monoamines in suicidal behavior.

Cerebrospinal fluid (CSF), urine, platelet and neuroendocrine challenge tests of monoaminergic function give evidence of monoamines, especially serotonin, playing an important role in suicidal behavior. However, additional clinical, social and biochemical factors are necessary to better define suicide-prone psychiatric patients.

Biogenic Monoamines↗

PubMed1993

Evaluation of ethanol effects on PLC signal transduction pathways using cell lines of neuronal origin.

Human neuroblastoma cells SH-SY5Y and neuroblastoma-glioma cells NG 108-15 have been used as models for the elucidation of the effects of ethanol on receptor-mediated phospholipase C activity, c-fos mRNA expression and protein kinase C activity. Cells were exposed to ethanol (0-200 mM) for varying periods up to seven days. Agonist stimulated events were obtained in NG 108-15 cells with bradykinin and in SH-SY5Y cells with carbachol. Chronic ethanol exposure reduced the agonist-stimulated formation of inositol 1,4,5-trisphosphate in NG 108-15 cells and in SH-SY5Y cells. 100 mM ethanol for seven days increased the membrane bound and cytosolic forms of protein kinase C activity in SH-SY5Y cells. Carbachol (1 mM) induced a maximal c-fos mRNA response after 40 minutes in SH-SY5Y cells, an effect that could be mimicked through protein kinase C stimulation by phorbol esters.

Bradykinin↗