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C Bianchi

Publications and source records attributed to C Bianchi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effects of cholecystokinin tetrapeptide (CCK(4)) and anxiolytic drugs on the electrically evoked [(3)H]5-hydroxytryptamine outflow from rat cortical slices.

The outflow of [(3)H]5-hydroxytryptamine ([(3)H]5-HT) from electrically stimulated rat cortical slices was measured to ascertain the modulatory role of endogenous cholecystokinin (CCK) on the amine outflow and to test the hypothesis that different anxiolytic compounds inhibit 5-HT secretion. The [(3)H]5-HT outflow evoked at 10 Hz was increased up to +30% by CCK(4) 300-1000 nM, the effect being prevented by the CCK(B) receptor antagonist GV 150013, 3 nM. The limited sensitivity to CCK(4) seemed to depend on 5-HT auto-receptor feedback because pre-treatment with 100 nM methiothepin enhanced the [(3)H]5-HT outflow and lowered the CCK(4) threshold concentration from 300 to 30 nM. In addition, pre-treatment with 1 microM bacitracin to inhibit CCK metabolism increased [(3)H]5-HT efflux. This effect was concentration-dependently counteracted by GV150013 suggesting the presence of an endogenous CCK positive modulation. GV150013 30 nM, the 5-HT(1A) partial agonist buspirone 300 nM and the GABA(A) receptor modulator diazepam 10 nM, known to have anxiolytic properties, all significantly reduced the [(3)H] amine outflow from cortical slices by about 20%. This inhibition depended on their interaction with their respective receptors, which seemed to restrain the activity of functionally interconnected glutamatergic interneurones. In fact, APV (50 microM) and NBQX (10 microM) prevented the effect of the anxiolytic compounds. Thus, anxiolytic drugs with different receptor targets can reduce 5-HT outflow by dampening the glutamatergic signal, and in turn, the secretory process of the serotonergic nerve ending.

Adamantane↗
PubMed2001

Biochemical and structural evidence for pig myocardium adherens junction disruption by cardiopulmonary bypass.

BACKGROUND: Given that cardiopulmonary bypass (CPB) is associated with edema and heart dysfunction and that adherens junctions may regulate vascular permeability barrier integrity and cardiomyocyte function, we investigated adherens junction protein steady-state levels in a pig model of CPB. METHODS AND RESULTS: Pigs were subjected to normothermic CPB for 90 minutes, followed by post-CPB perfusion for 90 minutes. Atrial and ventricular myocardium tissue samples were harvested before institution of bypass (basal levels) and at the end of post-CPB perfusion. Adherens junctions were analyzed by either total lysate or cadherin immunoprecipitates that were immunoblotted for pan-cadherin, VE-cadherin, beta-catenin, and gamma-catenin. Adherens junction solubility was addressed with Triton X-100 extraction. Frozen tissue sections were labeled with the same antibodies, and adherens junctions were visualized by confocal microscopy. Immunoblotting of total lysates revealed an increase in smaller-molecular-weight fragments of VE-cadherin, beta-catenin, and gamma -catenin after post-CPB perfusion, indicating partial protein degradation. Smaller-molecular-weight fragments recognized by VE-cadherin and beta-catenin antibodies were also obtained from VE-cadherin immunoprecipitation, indicating degradation of endothelial cell adherens junctions. A prominent increase in adherens junction complex solubility was observed in post-CPB perfusion samples. Confocal microscopy of hearts obtained before CPB showed a continuous, homogeneous pattern of cell-cell labeling that contrasted with an irregular, discontinuous, punctuate, or zigzag pattern observed in post-CPB perfusion samples, corroborating biochemical data. CONCLUSIONS: These results indicate that CPB is associated with signs of degradation of endothelial and cardiomyocytes adherens junctions, pointing to a molecular mechanism leading to increased vascular permeability and cardiomyocyte dysfunction.

Adherens Junctions↗
PubMed2001

Effects of two-carbon bridge region methoxylation of benztropine: discovery of novel chiral ligands for the dopamine transporter.

6-Methoxylated and 8-oxygenated benztropines were prepared and evaluated for their DAT and SERT activity (binding and uptake inhibition). Methoxylation at the two-carbon bridge of benztropine produced a novel class of potent and selective DAT ligands. An interesting enantioselectivity was also observed for this new class of chiral benztropines. The inactivity of the 8-oxygenated analogues seems to point out that, unlike cocaine and its analogues, interactions of benztropine ligands with DAT may be strongly governed by the nitrogen atom.

Benztropine↗
PubMed2001

Evolution of the E2 region of hepatitis C virus in an infant infected by mother-to-infant transmission.

To demonstrate vertical transmission of hepatitis C virus from an HCV infected woman and to assess the evolution of HCV quasispecies in the infant, the variable E2 region was analyzed in one mother-infant pair at birth and in serial samples from the infected baby. Sequence analysis of the E2 region obtained by means of direct sequencing of PCR products of mother-infant pair at birth, showed that the sequence of the dominant strain in the infant was related closely but not identical to that of her mother. The HCV population in mother-infant pair at birth and in serial samples of the infant was analyzed by polymerase-chain reaction-mediated Single Strand Conformational Polymorphism analysis (SSCP), which can distinguish DNA fragments of the same size as different electrophoretic migration of single stranded DNA. Single Strand Polymorphism analysis revealed that the infant was infected with two mutant genomes whereas the mother had a unique variant. The prevalent strain detected in the baby was not dominant in the mother at delivery and the pattern of quasispecies in the infant at birth was not the same as her mother, suggesting that the infant acquired the infection in utero. Changes in the dominant strain and evolution of the pattern of quasispecies in the infant from the 10th month of age were possibly due to the immune selection of escape mutants.

Amino Acid Sequence↗
PubMed2001

Rat aortic smooth muscle cell density affects activation of MAP kinase and Akt by menadione and PDGF homodimer BB.

Mitogen-activated protein kinases (MAPK) and protein kinase B (PKB or Akt) are major signal transduction molecules regulating cell proliferation, differentiation, and apoptosis. We examined how cultured rat aortic vascular smooth muscle cells (VSMC) at different cell densities respond to selected stimuli and how this is reflected in the two distinct (MAPK and Akt) and yet cross-talking signaling pathways. VSMC were cultured to 100% confluence, reaching contact inhibition, and to 60-70% confluence, as sparse, proliferating cells. They were treated with menadione (an intracellular generator of O(-2)) and/or platelet-derived growth factor homodimer BB (PDGF). In sparse cells, menadione or PDGF alone activated ERK, and together the effect was synergistic, whereas in confluent cells menadione's and PDGF's activations of ERK were, at most, additive. Activation of the upstream ERK kinase (MEK-1) paralleled ERK activation except in sparse cells in which the synergistic effects of menadione and PDGF on ERK could not be fully accounted for by MEK-1 activation. Another member of the MAPK family, p38, did not show significant changes. Akt activation by PDGF alone was present under both cell culture conditions; Akt activation is blocked by menadione. Co-incubation with the reducing agent dithiothreitol or calcium chelators (EDTA/EGTA) inhibited partially or completely menadione's effects on MEK/ERK and Akt pathways, as well as menadione's effects on PDGF-induced ERK and Akt activations. These data suggest that in VSMC, the state of cell confluence determines how distinct pathways of MAPK activation cross talk. In addition while PDGF may function as a survival factor by inducing Akt activation, menadione could promote apoptosis by inhibiting PDGF-induced Akt activation independent of cell density. The effects of menadione, but not those of PDGF, are more dependent on the cellular redox status and extracellular calcium.

Animals↗
PubMed2001

Serotonin-induced human coronary microvascular contraction during acute myocardial ischemia is blocked by COX-2 inhibition.

Since serotonin (5-HT) is implicated in exacerbating acute coronary syndromes, we studied the reactivity of atrial coronary arterioles (70-140 microm) of atherosclerotic patients undergoing cardiac surgery to 5-HT, substance P (Sub P), and sodium nitroprusside by video-microscopy. Before ischemia, 5-HT-induced relaxation was not affected by NS398 (cyclooxygenase inhibitor), H2O2 or U63557A (thromboxane A2 synthase inhibitor), but was reduced by L-NNA. 5-HT elicited a potent contractile response after ischemia that was inhibited by NS398, Indo, and U63557A. While Sub P relaxation was decreased after ischemia, SNP relaxation was unchanged. The mRNA steady-state levels of NOS-3, NOS-2, prostacyclin synthase, and COX- 1 were not altered by ischemia. COX-2 mRNA and protein levels (Westernblotting), however, were increased (mean +/- SEM) 2.4 +/- 0.4 and 3.2 +/- 0.7 fold, respectively, in ischemic atrium corroborating with the immunohistochemistry of atrial tissue. It is concluded that myocardial ischemia enhanced contractile response of coronary arterioles to 5-HT maybe due to the stimulated prostaglandin release (likely thromboxane A2) secondary to induction of COX-2 expression. These findings may have implications regarding the cause of coronary spasm during acute myocardial ischemia.

Aged↗
PubMed2001

Properties of multidrug-resistant, ESBL-producing Proteus mirabilis isolates and possible role of beta-lactam/beta-lactamase inhibitor combinations.

At our institution, isolation rates of clinical strains of ESBL-producing Proteus mirabilis increased to 8.8% of all P. mirabilis isolates during the period 1997-1999. To evaluate the susceptibility of ESBL-producing P. mirabilis strains against commonly used drugs, we studied 50 non-duplicated isolates selected on the basis of synergy between clavulanate and beta-lactams (ceftazidime, aztreonam, cefotaxime, and ceftriaxone). The presence of ESBL-coding genes was confirmed by colony hybridization with bla(TEM-1) and bla(SHV-1) probes. Minimum inhibitory concentrations of several antimicrobial agents for each isolate were obtained using the Etest method. All strains were encoding for TEM-derived enzymes. Gene sequencing showed that at least three different genes (TEM-15, TEM-20, and TEM-52) were present. These enzymes have not been previously reported in P. mirabilis. Isolates were characterized by: (a) reduced susceptibility or resistance to third- and fourth-generation cephalosporins (MIC > or = 2 mg/l), (b) resistance to piperacillin that was abolished by tazobactam (MIC > or = 256 vs. < or = 2 mg/l, respectively), (c) multiple antibiotic resistance that included gentamicin, fluoroquinolones and co-trimoxazole. Therapeutic failure and lack of eradication of ESBL-positive P. mirabilis by third-generation cephalosporins has been repeatedly observed both at our Institution and elsewhere. Piperacillin-tazobactam, as well as amikacin and meropenem appear to be important therapeutic options for infections due to multidrug-resistant, ESBL-producing P. mirabilis isolates.

Anti-Bacterial Agents↗
PubMed2001

Presynaptic group I and II metabotropic glutamate receptors oppositely modulate striatal acetylcholine release.

The effect of metabotropic glutamate receptor agonists and antagonists on KCl (20 mm)-induced endogenous acetylcholine release from rat striatal synaptosomes was investigated. The group I agonist (S)-3,5-dihydroxyphenylglycine (DHPG), 1-1000 nm, potentiated in a concentration-dependent way the KCl-induced acetylcholine release, reaching maximal efficacy at 100 nm (+93 +/- 14%). The effect of DHPG (10 nm) was counteracted by coapplication of (7-hydroximino)cyclopropan-b-chromen-1a-carboxylate (CPCCOEt), 10 microm, a metabotropic glutamate receptor type one selective antagonist, and 2-methyl-6-(phenylethynyl)pyridine (MPEP), 10 microm, a metabotropic glutamate receptor type five selective antagonist, but not by application of either antagonist alone. The group II agonist (2S, 1'R, 2'R, 3'R)-2-(2,3-dicarboxycyclopropyl)glycine (DCG-IV), 1-1000 nm, inhibited in a concentration-dependent way the KCl-induced acetylcholine release displaying maximal efficacy at 300 nm (-32 +/- 2%). The effect of DCG-IV 300 nm was counteracted by the group II selective antagonist (2S)-alpha-ethylglutamic acid (EGLU), 300 microm. The group III agonist L-amino-4-phosphonobutyric acid (L-AP4) failed to alter the KCl-induced acetycholine release up to 300 microm. We conclude that metabotropic glutamate receptors belonging to group I and II are located on the axon terminals of striatal cholinergic interneurons, their activation resulting in facilitation and inhibition, respectively, of acetylcholine release.

Acetylcholine↗
PubMed2001

A prospective, longitudinal study of the long-term effect of treatment on bone density in children with celiac disease.

OBJECTIVE: Because osteopenia is a frequent complication of celiac disease, we evaluated the impact of a long-term gluten-free diet (GFD), initiated during childhood, on bone density. study design: Patients with celiac disease (n = 19; mean age, 14.2 +/- 2.6 years) were studied after 4.3 +/- 0.6 years of GFD. Bone density had been measured at diagnosis and after 1 year of GFD. We also studied 211 healthy children as a control group. Bone mineral density was measured by dual-energy x-ray absorptiometry. Intact parathyroid hormone (PTH) and bone-specific alkaline phosphatase (BALP) levels were measured in serum, and N-terminal telopeptide of type I collagen (NTx) was measured in urine. RESULTS: Although at diagnosis bone mineral content, bone area, and bone mineral density were significantly lower than in control subjects, the 3 measurements were normal after GFD. None of the patients on a GFD showed elevated values of PTH. Patients on a GFD had BALP (110.2 +/- 67.2 U/L) and NTx levels (261.9 +/- 187.8 nmol bone collagen equivalents/mmol creatinine) that were significantly higher than those of control subjects. The levels of BALP and NTx were significantly higher in patients with good compliance with the GFD, compared with patients with poorer compliance. CONCLUSIONS: This study shows that bone mineral content, bone area, and bone mineral density improve significantly with a GFD.

Absorptiometry, Photon↗
PubMed2001

Oscillation in the activities of MEK/ERK1/2 during cardiopulmonary bypass in pigs.

BACKGROUND: Because cardiopulmonary bypass (CPB) is associated with edema and vasoreactive dysfunction and ERK1/2 pathway is involved in vascular contractility and permeability, a time course study was performed to monitor MEK/ERK1/2/Elk-1 activities during CPB. METHODS: Pigs were subjected to normothermic CPB for 90 minutes followed by post-CPB perfusion for 180 minutes. Atrial myocardium was sampled before CPB, 5 minutes after CPB onset, 5 minutes after weaning from CPB, and at the end of post-CPB. Skeletal muscle and mesenteric vessels samples were harvested before CPB, 5 minutes after CPB institution, and every 30 minutes thereafter to the end of post-CPB. Samples were analyzed by immunoblotting and immunofluorescence microscopy with the use of specific antibodies against active (phosphorylated) forms of ERK1/2, MEK1/2, and Elk-1. RESULTS: Pigs that were subjected to CPB showed an increase in phospho-ERK1/2 after 30 minutes of CPB, followed by a decrease after 90 minutes. Another phosphorylation peak was observed 30 to 60 minutes of post-CPB, followed by a decrease to below baseline at the end of reperfusion. MEK1/2 and Elk-1 activation profiles paralleled ERK1/2 activity peaks. Control samples showed no significant increase above basal levels. CONCLUSIONS: Activation of MEK/ERK1/2/Elk-1 pathways closely follows major CPB surgical manipulations (institution and termination) and could be related to morbidity during and after CPB.

Animals↗
PubMed2001

Inactivation of the MEK/ERK pathway in the myocardium during cardiopulmonary bypass.

OBJECTIVES: A general pro-inflammatory response after cardiopulmonary bypass (CPB) may involve changes in signal transduction and in part be responsible for arrhythmias and myocardial dysfunction after cardiac surgery. The MEK/ERK (mitogen-activated protein kinase kinase/extracellular regulated kinase) pathway is common to many stimuli and may play a pivotal role in morbidity associated with CPB. We investigated the changes in MEK/ERK pathway and related enzymes after CPB in pigs. METHODS: We examined ventricular and atrial tissue from pigs before 90 minutes of normothermic CPB and after 90 minutes of post-CPB perfusion. The activities and protein levels of kinases MEK1/2, ERK1/2, a cellular tyrosine kinase (c-Src), protein kinase B (Akt), and the protein levels of mitogen-activated protein kinase phosphatase (MKP-1) were studied by immunoblotting ventricular and atrial myocardium lysates and labeling sections with antibodies that recognize the activated forms of the kinases and the phosphatase. Control pigs were subjected to sternotomy and heparinization but not CPB. RESULTS: We found a consistent inactivation of MEK/ERK pathway in both ventricular and atrial myocardium with an increase in MKP-1, a negative regulator of ERK1/2. The activities and protein levels of c-Src and Akt were not significantly modified before or after CPB, suggesting a certain degree of specificity for the MEK/ERK pathway. Such changes were not observed in controls. The decrease of ERK1/2 and MEK1/2 phosphorylation 90 minutes after termination of CPB (as well as the increase of nuclear MKP-1 protein levels) was also apparent by confocal microscopy. CONCLUSIONS: These results collectively reveal a prevalence of inhibitory mechanisms in the MEK/ERK signal transduction machinery in myocardium subjected to CPB.

Animals↗
PubMed2001

Macroamylasemia attributable to gluten-related amylase autoantibodies: a case report.

BACKGROUND: Macroamylasemia (MA) is a benign condition caused by circulating macroamylase complexes of pancreatic or salivary amylase bound to plasma proteins, which cannot be cleared by the renal glomeruli. In most cases, the macromolecular amylase represents a complex of normal amylase and either immunoglobulin A or G and may be a specific antigen-antibody complex. Celiac disease (CD) is a permanent intolerance to ingested gluten that results in immunologically mediated inflammatory damage of the small intestinal mucosa. Several recent population-based serologic surveys have shown CD to be a common disorder, possibly affecting 1 in 200 to 250 individuals in most countries studied, including the United States, where overt CD is rare, indicating a high proportion of subclinical disease. The diagnosis of CD currently rests on the histological demonstration of the characteristic lesion in the small intestine and the subsequent clinical response to the introduction of a gluten-free diet. MA associated with CD has been described in adult patients, and in a few cases, MA decreased or resolved after a strict gluten-free diet. A few single cases of MA have been described in childhood, but no association with CD has been reported so far. We report a girl with CD, autoimmune thyroiditis, and MA, in whom CD-related antibodies to amylase and to exocrine pancreas tissue resolved with a gluten-free diet. CASE REPORT: An 11-year-old girl was referred for chronic abdominal pain and growth retardation associated with persistent hyperamylasemia and suspected chronic pancreatitis. We confirmed elevated serum amylase, normal serum lipase, and very low 24-hour urine amylase and amylase clearance/creatinine clearance ratio, consistent with MA. Serologic tests for CD were positive, and the diagnosis was confirmed by small bowel biopsy showing subtotal villous atrophy. Thyroid function tests showed a pronounced hypothyroidism, associated with high titers of thyroid microsomal and thyroglobulin antibodies. Screening for other autoantibodies-including antinuclear, islet cell, glutamic acid decarboxylase, protein tyrosine phosphatase islet antigen 512, adrenal gland, and cytoplasmic neutrophil granulocyte antibodies-was negative. A diagnosis of CD, MA, and hypothyroidism attributable to autoimmune thyroiditis was made. A gluten-free diet and oral replacement with L-thyroxine was started with clinical improvement. Serum amylase and amylase clearance/creatinine clearance ratio normalized, consistent with resolution of MA. STUDY DESIGN AND METHODS: The patient's serum samples were obtained at the time of CD diagnosis and at 3 and 12 months after instituting a gluten-free diet. Serum samples from 10 consecutive untreated celiac children were disease controls, and 39 participants with no gastrointestinal symptoms and no family history of CD served as healthy controls. The origin of MA as determined by complexes of amylase with circulating immunoglobulins was tested by the measurement of amylase on supernatants after precipitation of immune complexes with either protein A Sepharose or polyethylene glycol. The precipitation of >60% of amylase activity was consistent with the presence of MA. Immunoglobulin G (IgG) and immunoglobulin A (IgA) circulating autoantibodies to amylase were measured using recently developed enzyme-linked immunosorbent assay (ELISA), using porcine amylase as antigen. Results were expressed as arbitrary units (AUs). Statistical analysis was performed by Student's t test for unpaired data. IgA and IgG antibodies to exocrine pancreas tissue were detected by indirect immunofluorescence on human pancreas cryosections. RESULTS: Serum immunoprecipitation with either protein A Sepharose or polyethylene glycol reduced amylase activity from 1698 to 89 U/L (94.8%) and to 75 U/L (95.6%), with only marginal reduction in control serum samples. The ELISA for autoantibodies to amylase detected high values, both IgA (3531 AU) and IgG (1855 AU), in the serum sample from the patient at CD diagnosis. IgA autoantibodies (mean +/- standard deviation) were 3.4 +/- 2.5 AU in healthy controls, and 2.1 +/- 1.2 AU in celiac controls; IgG autoantibodies were 10 +/- 4.8 AU in healthy controls and 8.5 +/- 3.2 AU, respectively. Autoantibodies to exocrine pancreas tissue were documented in patient sera at the time of CD diagnosis, both IgA and IgG, but not in control groups. Preincubation of patient's serum with excess of alpha-amylase specifically inhibited antibody binding to coated amylase in the ELISA, and partially inhibited immunoreactivity to exocrine pancreas. Autoantibodies to alpha-amylase and to exocrine pancreas declined in CD patients after institution of a gluten-free diet. CONCLUSIONS: Few cases of MA have been described in children, and in all amylase determination was part of the clinical investigation for abdominal pain or trauma. (ABSTRACT TRUNCATED)

Amylases↗
PubMed2001

Asbestos exposure in malignant mesothelioma of the pleura: a survey of 557 cases.

A series of 557 malignant mesotheliomas of the pleura diagnosed in the Trieste-Monfalcone area, Italy, in the period 1968-2000 were reviewed. The series included 492 men and 65 women, aged between 32 and 93 years (median age 69 years). Necropsy findings were available in 456 cases (82%). Occupational histories were obtained from the patients themselves or from their relatives by personal or telephone interviews. Routine lung sections were examined for asbestos bodies in 442 cases. In 109 cases isolation and counting of asbestos bodies were performed. A majority of people had histories of working in the shipyards. Asbestos bodies were observed in lung sections in 67% of the cases. Lung asbestos body burdens after isolation ranged between 20 bodies and about 10 millions of bodies/g dried tissue. Latency periods (time intervals between first exposure to asbestos and death) ranged between 14 and 75 years (mean 48.8 years, median 51.0). Latency periods among insulators and dock workers were shorter than among the other categories. High asbestos consumption occurred in many countries in the 1960s and in the 1970s. The data on latency periods obtained in the present study suggest that a world mesothelioma epidemic has to be expected in the coming decades.

Adult↗
PubMed2001

Clinical trial of a monophasic estroprogestin oral formulation containing 20 micrograms ethinyl estradiol and 75 micrograms gestodene.

The attempt to decrease the hormonal components of combined estrogen/progestin-containing oral formulations has led to use of low-dose formulations. The monophasic formulation containing ethinyl estradiol 20 micrograms (EE20) plus gestodene 75 micrograms (GSD75) was studied in an open, non-comparative, multicenter, clinical trial investigating its efficacy, safety, effects on body weight, blood pressure and sexual function. To evaluate the impact on sexual function, the Golombok Rust Questionnaire on Sexual Satisfaction (GRISS) was used. The study population comprised 216 women treated for 1 year. The EE20/GSD75 formulation did not show any significant effect on blood pressure, hematological parameters, body weight or sexual function. The treatment was well tolerated with a high compliance rate by the patients, with a low rate of estrogen-dependent symptoms. Moreover, there was no overall effect on sexual function, with no disturbance of sexual behavior or activity. In conclusion, our data show that the EE20/GSD75 has a very good tolerability profile, without any significant side-effects.

Adult↗
PubMed2000

Assessment of substitution in the second pharmacophore of Dmt-Tic analogues.

The Dmt-Tic pharmacophore exhibits potent delta-opioid receptor antagonism. Analogues with substitutions in the second pharmacophore with (1, 1') or without a COOH function (2-9) were synthesized: several had high delta affinity (1', 2, 7, and 9), but exhibited low to non-selectivity toward mu receptors similar to H-Dmt-Tic-amide and H-Dmt-Tic-ol. Functional bioactivity indicated high delta antagonism (pA2 7.4-7.9) (1', 2, and 9) and modest mu agonism, pEC50 (6.1-6.3) (1', 2, 8, and 9), but with Emax values analogous to dermorphin. These Dmt-Tic analogues with mixed delta antagonist/mu agonist properties would appear to be better candidates as analgesics than pure mu agonists.

Analgesics↗
PubMed2000

Nicotinic modulation of [(3)H]D-aspartate outflow from cultured cerebellar granule cells.

The effect of nicotine on basal and electrically evoked (20 Hz for 20 sec) [(3)H]D-aspartate efflux (assumed as an index of transmitter release) was studied in rat cerebellar granule primary cultures. Nicotine (10-100 nM) increased the basal efflux two to three times and concentration-dependently enhanced the electrically evoked efflux up to ten times. Higher drug concentration (1 microM) underwent rapid desensitization. Facilitation of the efflux was similarly reduced by the nicotinic acetylcholine receptor antagonists, alpha-bungarotoxin and mecamylamine, suggesting the involvement of at least two receptor subtypes containing and lacking alpha(7) subunits, respectively. Since the increased efflux induced by nicotine in granule cells kept at rest or depolarized by KCl 15 mM was antagonized by tetrodotoxin, the involvement of sodium channels by receptors located at preterminal sites was suggested. Taken together, these findings emphasize the role of the cholinergic input in granule cell function and in glutamatergic signaling.

Acetylcholine↗
PubMed2000

Increased pulmonary vascular contraction to serotonin after cardiopulmonary bypass: role of cyclooxygenase.

BACKGROUND: Pulmonary vascular resistance is frequently elevated after cardiopulmonary bypass (CPB). We examined if altered pulmonary microvascular reactivity to serotonin (5-HT) is due to altered expression of isoforms of nitric oxide synthase (NOS) or cyclooxygenase (COX). MATERIALS AND METHODS: Pigs (n = 8) were heparinized and placed on total CPB for 90 min and then perfused off CPB for 90 min. Noninstrumented pigs (n = 6) served as controls for vascular studies. Relaxation responses (% of precontraction) of microvessels (60-150 microm in diameter) were examined in vitro in a pressurized (20 mm Hg) no-flow state with video microscopic imaging. Expression of eNOS, iNOS, and inducible (COX-2) and constitutive (COX-1) cyclooxygenase was examined with Western blotting and reverse transcription polymerase chain reaction. RESULTS: Pulmonary vascular resistance (PVR) increased from 316 +/- 39 mm Hg x s/cm(5) at baseline to 495 +/- 53 at 60 min and 565 +/- 62 at 90 min after termination of CPB. 5-HT elicited a relaxation response (46.8 +/- 11. 8%) in precontracted control microvessels. This response was not affected by the NOS inhibitor N(G)-nitro-l-arginine. After CPB, pulmonary microvessels contracted significantly to 5-HT (-29 +/- 27%, P < 0.05 vs control). This response was partially inhibited (7 +/- 20%, P = 0.06) in the presence of the COX-2 inhibitor NS398, but was unaffected by the thromboxane synthase inhibitor U63557A (-20 +/- 19%). Expression of iNOS or COX-1 was not changed after CPB. Protein and mRNA expressions of COX-2 both increased significantly after CPB, while that of eNOS decreased by approximately 50%. CONCLUSIONS: PVR increased after CPB. This was associated with a hypercontractile response of isolated pulmonary microvessels to 5-HT that was in part mediated by the release of prostaglandins (but not thromboxane) and associated with increased expression of COX-2 and with decreased expression of eNOS.

Animals↗