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Liu G, Kaneko M, Yoshioka K, Obara K, Tanaka Y. Platelet-activating factor (PAF) strongly enhances contractile mechanical activities in guinea pig and mouse urinary bladder. Sci Rep 2022; 12:2783. [PMID: 35177680 PMCID: PMC8854422 DOI: 10.1038/s41598-022-06535-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 01/31/2022] [Indexed: 11/09/2022] Open
Abstract
In this study, we investigated the effects of platelet-activating factor (PAF) on the basal tone and spontaneous contractile activities of guinea pig (GP) and mouse urinary bladder (UB) smooth muscle (UBSM) tissues to determine whether PAF could induce UBSM tissue contraction. In addition, we examined the mRNA expression of the PAF receptor, PAF-synthesizing enzyme (lysophosphatidylcholine acyltransferase, LPCAT), and PAF-degrading enzyme (PAF acetylhydrolase, PAF-AH) in GP and mouse UB tissues using RT-qPCR. PAF (10-9-10-6 M) strongly enhanced the basal tone and spontaneous contractile activities (amplitude and frequency) of GP and mouse UBSM tissues in a concentration-dependent manner. The enhancing effects of PAF (10-6 M) on both GP and mouse UBSM contractile activities were strongly suppressed by pretreatment with apafant (a PAF receptor antagonist, GP: 10-5 M; mouse: 3 × 10-5 M). The PAF receptor (Ptafr), LPCAT (Lpcat1, Lpcat2), and PAF-AH (Pafah1b3, Pafah2) mRNAs were detected in GP and mouse UB tissues. These findings reveal that PAF strongly enhances the contractile mechanical activities of UBSM tissues through its receptor and suggest that the PAF-synthesizing and -degrading system exists in UBSM tissues. PAF may serve as both an endogenous UBSM constrictor and an endogenous mediator leading to detrusor overactivity.
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Affiliation(s)
- Ge Liu
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba, 274-8510, Japan
| | - Mizuki Kaneko
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba, 274-8510, Japan
| | - Kento Yoshioka
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba, 274-8510, Japan
| | - Keisuke Obara
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba, 274-8510, Japan.
| | - Yoshio Tanaka
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba, 274-8510, Japan
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Lordan R, Tsoupras A, Zabetakis I. The Potential Role of Dietary Platelet-Activating Factor Inhibitors in Cancer Prevention and Treatment. Adv Nutr 2019; 10:148-164. [PMID: 30721934 PMCID: PMC6370273 DOI: 10.1093/advances/nmy090] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/11/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
Cancer is the second leading cause of mortality worldwide. The role of unresolved inflammation in cancer progression and metastasis is well established. Platelet-activating factor (PAF) is a key proinflammatory mediator in the initiation and progression of cancer. Evidence suggests that PAF is integral to suppression of the immune system and promotion of metastasis and tumor growth by altering local angiogenic and cytokine networks. Interactions between PAF and its receptor may have a role in various digestive, skin, and hormone-dependent cancers. Diet plays a critical role in the prevention of cancer and its treatment. Research indicates that the Mediterranean diet may reduce the incidence of several cancers in which dietary PAF inhibitors have a role. Dietary PAF inhibitors such as polar lipids have demonstrated inhibitory effects against the physiological actions of PAF in cancer and other chronic inflammatory conditions in vitro and in vivo. In addition, experimental models of radiotherapy and chemotherapy demonstrate that inhibition of PAF as adjuvant therapy may lead to more favorable outcomes. Although promising, there is limited evidence on the potential benefits of dietary PAF inhibitors on cancer prevention or treatment. Therefore, further extensive research is required to assess the effects of various dietary factors and PAF inhibitors and to elucidate the mechanisms in prevention of cancer progression and metastasis at a molecular level.
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Affiliation(s)
- Ronan Lordan
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Alexandros Tsoupras
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Ioannis Zabetakis
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
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Chini M, Tsoupras AB, Mangafas N, Tsogas N, Papakonstantinou VD, Fragopoulou E, Antonopoulou S, Gargalianos P, Demopoulos CA, Lazanas MC. Effects of HAART on platelet-activating factor metabolism in naive HIV-infected patients I: study of the tenofovir-DF/emtricitabine/efavirenz HAART regimen. AIDS Res Hum Retroviruses 2012; 28:766-75. [PMID: 22050695 DOI: 10.1089/aid.2011.0202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Platelet-activating factor (PAF) is implicated in human immunodeficiency virus (HIV)-related manifestations. Increased PAF synthesis has been recently detected in HIV-infected patients. In this study, we examined in naive HIV-infected patients the in vivo effects of a highly active antiretroviral therapy (HAART) regimen, containing tenofovir-DF/emtricitabine/efavirenz, on PAF metabolism. The specific activities of PAF basic biosynthetic enzymes, PAF-cholinephosphotransferase (PAF-CPT) and lyso-PAF-acetyltransferase (lyso-PAF-AT), but also the ones of PAF-basic catabolic enzymes, PAF acetylhydrolase (PAF-AH) in leukocytes and platelets, and lipoprotein-associated-phospholipase-A(2) (LpPLA(2)) in plasma, were measured in blood samples of eight asymptomatic naive male HIV-infected patients just before and after 1, 3, and 6 months of treatment. CD4 cell counts, viral load, and several biochemical markers were also measured in the same blood samples of these patients. The repeated measures ANOVA and the Pearson r criterion were used to study statistical differences and correlations-partial correlations, while linear mixed models were conducted in order to estimate association(s) between time-dependent changes in these factors. Before treatment, the activities of PAF-CPT in leukocytes and LpPLA(2) in plasma were found to be inversely correlated with CD4 cell counts and positively correlated with the viral load. After 6 months of treatment, the activities of basic PAF-biosynthetic enzymes, PAF-CPT and lyso-PAF-AT, were both reduced in leukocytes. At 6 months, PAF-AH activity was also reduced in these cells, while LpPLA(2) remained stable. The reduction of PAF-CPT occurred even from the first month, while there is a time-dependent correlation between the increase of CD4 and the decrease of both viral load and PAF-CPT of leukocytes during treatment. Apart from its classical antiretroviral activities the tenofovir-DF/emtricitabine/efavirenz regimen also exhibited favorable effects on PAF metabolism and therefore may also display beneficial effects in some HIV-related conditions, such as cardiovascular disease (CVD), in which PAF is implicated.
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Affiliation(s)
- Maria Chini
- 3rd Internal Medicine Department-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | | | - Nikos Mangafas
- 3rd Internal Medicine Department-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - Nikos Tsogas
- 3rd Internal Medicine Department-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | | | | | | | - Panagiotis Gargalianos
- 1st Internal Medicine Department-Infectious Diseases Unit, “G. Gennimatas” Hospital, Athens, Greece
| | | | - Marios C. Lazanas
- 3rd Internal Medicine Department-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
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Frisardi V, Panza F, Seripa D, Farooqui T, Farooqui AA. Glycerophospholipids and glycerophospholipid-derived lipid mediators: A complex meshwork in Alzheimer’s disease pathology. Prog Lipid Res 2011; 50:313-30. [DOI: 10.1016/j.plipres.2011.06.001] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 06/09/2011] [Accepted: 06/09/2011] [Indexed: 10/18/2022]
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Tsoupras AB, Chini M, Mangafas N, Tsogas N, Stamatakis G, Tsantila N, Fragopoulou E, Antonopoulou S, Gargalianos P, Demopoulos CA, Lazanas MC. Platelet-Activating Factor and Its Basic Metabolic Enzymes in Blood of Naive HIV-Infected Patients. Angiology 2011; 63:343-52. [DOI: 10.1177/0003319711420608] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | - Maria Chini
- 3rd Internal Medicine Department, Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - Nikos Mangafas
- 3rd Internal Medicine Department, Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - Nikos Tsogas
- 3rd Internal Medicine Department, Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - George Stamatakis
- Department of Chemistry, National and Kapodistrian University of Athens, Greece
| | - Nektaria Tsantila
- Department of Chemistry, National and Kapodistrian University of Athens, Greece
| | - Elizabeth Fragopoulou
- Department of Dietetics and Nutritional Science, Harokopio University, Athens, Greece
| | - Smaragdi Antonopoulou
- Department of Dietetics and Nutritional Science, Harokopio University, Athens, Greece
| | - Panagiotis Gargalianos
- 1st Internal Medicine Department, Infectious Diseases Unit, “G. Gennimatas” Hospital, Athens, Greece
| | | | - Marios C. Lazanas
- 3rd Internal Medicine Department, Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
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Tsoupras AB, Chini M, Tsogas N, Lioni A, Tsekes G, Demopoulos CA, Lazanas MC. In vitro anti-inflammatory and anti-coagulant effects of antibiotics towards Platelet Activating Factor and thrombin. J Inflamm (Lond) 2011; 8:17. [PMID: 21736752 PMCID: PMC3162514 DOI: 10.1186/1476-9255-8-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 07/07/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sepsis is characterized as a systemic inflammatory response that results from the inability of the immune system to limit bacterial spread during an ongoing infection. In this condition the significant mediator of inflammation Platelet Activating Factor (PAF) and the coagulant factor thrombin are implicated. In animal models, treatment with PAF-antagonists or co-administration of antibiotics with recombinant-PAF-Acetylhydrolase (rPAF-AH) have exhibited promising results. In order to examine the putative anti-inflammatory and/or antithrombotic interactions between antibiotic treatment used in sepsis with PAF and/or thrombin, we studied the in vitro effects of these compounds towards PAF or/and thrombin related activities and towards PAF basic metabolic enzymes. METHODS We assessed the inhibitory effect of these drugs against PAF or thrombin induced aggregation on washed rabbit platelets (WRPs) or rabbit Platelet Reach Plasma (rPRP) by evaluating their IC50 values. We also studied their effect on Cholinephosphotransferase of PAF (PAF-CPT)/Lyso-PAF-Acetyltransferase (Lyso-PAF-AT) of rabbit leukocytes (RLs), as well as on rabbit plasma-PAF-AH, the key enzymes of both de novo/remodelling PAF biosynthesis and PAF degradation, respectively. RESULTS Several antibiotics inhibited PAF-induced platelet aggregation of both WRPs and rPRP in a concentration-depended manner, with clarithromycin, azithromycin and amikacin exhibiting the higher inhibitory effect, while when combined they synergistically inhibited PAF. Higher concentrations of all antibiotics tested were needed in order to inhibit PAF induced aggregation of rPRP, but also to inhibit thrombin induced aggregation of WRPs. Concentrations of these drugs similar to their IC50 values against PAF activity in WRPs, inhibited also in vitro PAF-CPT and Lyso-PAF-AT activities of rabbit leukocytes, while only clarithromycin and azithromycin increased rabbit plasma-PAF-AH activity. CONCLUSIONS These newly found properties of antibiotics used in sepsis suggest that apart from their general actions, these drugs may present additional beneficial anti-inflammatory and anti-coagulant effects against the onset and establishment of sepsis by inhibiting the PAF/PAF-receptor and/or the thrombin/protease-activated-receptor-1 systems, and/or by reducing PAF-levels through both PAF-biosynthesis inhibition and PAF-catabolism induction. These promising in vitro results need to be further studied and confirmed by in vivo tests, in order to optimize the efficacy of antibiotic treatment in sepsis.
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Affiliation(s)
- Alexandros B Tsoupras
- Faculty of Chemistry, National & Kapodistrian University of Athens, Panepistimioupolis of Zografou, Athens, 15771, Greece
| | - Maria Chini
- 3rd Internal Medicine Dept.-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - Nickolaos Tsogas
- 3rd Internal Medicine Dept.-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - Athina Lioni
- 3rd Internal Medicine Dept.-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - George Tsekes
- 3rd Internal Medicine Dept.-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - Constantinos A Demopoulos
- Faculty of Chemistry, National & Kapodistrian University of Athens, Panepistimioupolis of Zografou, Athens, 15771, Greece
| | - Marios C Lazanas
- 3rd Internal Medicine Dept.-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
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Tsoupras A, Chini M, Tsogas N, Mangafas N, Demopoulos C, Lazanas M. In Vivo Effects of a Ginkgo Biloba Extract on Platelet Activating Factor Metabolism in Two Asymptomatic Hiv-Infected Patients. EUR J INFLAMM 2011. [DOI: 10.1177/1721727x1100900204] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ginkgo biloba products seem to protect from several pathological conditions, including HIV manifestations, where Platelet Activating Factor (PAF) is implicated. In the present study, we examined for the first time the in vivo effects of a standardized formulation of Ginkgo biloba extract (150 mg daily, per os) on PAF metabolism in blood cells and plasma of two male, asymptomatic HIV-infected patients, not receiving antiretroviral treatment, during a 9-month period. These patients differed at baseline in terms of duration of HIV infection, viral load levels, CD4 cell counts and Highly Active Antiretroviral Therapy (HAART) experience. In the first patient with early HIV infection, after an initial transient increase, a return of both plasma viral load and PAF biosynthetic enzyme activities in leukocytes to their baseline levels was observed during Ginkgo biloba use. As a result PAF degradation also remained low in this patient. The second patient with late but not advanced HIV infection, had higher levels of viral load and a lower CD4 cell count at baseline. The use of 150 mg of a Ginkgo biloba extract was probably insufficient to induce PAF degradation and/or to suppress the induction of PAF biosynthesis observed. At the same time, the initial high levels of viral load were further increased and CD4 cell counts were finally decreased during the study. The observed differences in PAF metabolism during Ginkgo use seem to be related to the initial heterogeneity of these patients. It appears that in some HIV-infected patients inhibition of the PAF/PAF-receptor system, along with a decrease/down-regulation of PAF-biosynthesis, illustrates a new potential role for Ginkgo biloba compounds in the treatment of HIV infection and its manifestations. However, more tests on a larger number of patients are needed in order to support these preliminary observations.
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Affiliation(s)
- A.B. Tsoupras
- Faculty of Chemistry, National and Kapodistrian University of Athens, Athens
| | - M. Chini
- 3rd Internal Medicine Department-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - N. Tsogas
- 3rd Internal Medicine Department-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - N. Mangafas
- 3rd Internal Medicine Department-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
| | - C.A. Demopoulos
- Faculty of Chemistry, National and Kapodistrian University of Athens, Athens
| | - M.C. Lazanas
- 3rd Internal Medicine Department-Infectious Diseases Unit, Red Cross General Hospital, Athens, Greece
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Tsantila N, Tsoupras AB, Fragopoulou E, Antonopoulou S, Iatrou C, Demopoulos CA. In Vitro and In Vivo Effects of Statins on Platelet-Activating Factor and Its Metabolism. Angiology 2010; 62:209-18. [DOI: 10.1177/0003319710375089] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Platelet activating factor (PAF) is implicated in cardiovascular disease (CVD). Statins are widely used in these situations. Therefore, we assessed their effect on the biological activities and metabolism of PAF. Several statins, including simvastatin, exhibited an inhibitory effect against PAF, comparable with that of PAF-inhibitors. Simvastatin also suppressed in vivo PAF-biosynthesis via the de novo pathway, in leukocytes of 6 simvastatin-treated volunteers. Total cholesterol and low-density lipoprotein cholesterol were also significantly decreased, whereas high-density lipoprotein cholesterol, triacylglycerol, EC50, and lag time were unaffected in these participants. Simvastatin with an intact lactone ring also inhibited PAF-activities, while incubation of human mesangial cells with it also resulted in decreased de novo PAF-biosynthesis. This suggests that these simvastatin-dependent effects are independent of its lactone ring. These new actions of statins should be further studied in PAF-implicated pathological conditions such as CVD, cancer, and renal disease.
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Affiliation(s)
- Nektaria Tsantila
- Laboratory of Biochemistry, Faculty of Chemistry, National and Kapodistrian University, Athens, Greece
| | - Alexandros B. Tsoupras
- Laboratory of Biochemistry, Faculty of Chemistry, National and Kapodistrian University, Athens, Greece,
| | | | | | - Christos Iatrou
- Nephrology Centre, “G. Papadakis” General Hospital of Nikea-Pireaus, Athens, Greece
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Tsoupras AB, Fragopoulou E, Nomikos T, Iatrou C, Antonopoulou S, Demopoulos CA. Characterization of the de novo biosynthetic enzyme of platelet activating factor, DDT-insensitive cholinephosphotransferase, of human mesangial cells. Mediators Inflamm 2008; 2007:27683. [PMID: 17710109 PMCID: PMC1939920 DOI: 10.1155/2007/27683] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Accepted: 03/08/2007] [Indexed: 11/18/2022] Open
Abstract
Platelet activating factor (PAF), a potent inflammatory mediator, is implicated in several proinflammatory/inflammatory diseases such as glomerulonephritis, glomerulosclerosis, atherosclerosis, cancer, allergy, and diabetes. PAF can be produced by several renal cells under appropriate stimuli and it is thought to be implicated in renal diseases. The aim of this study is the characterization of DTT-insensitive cholinephosphotransferase (PAF-CPT) of human mesangial cell (HMC), the main regulatory enzyme of PAF de novo biosynthetic pathway. Microsomal fractions of mesangial cells were isolated and enzymatic activity and kinetic parameters were determined by TLC and in vitro biological test in rabbit washed platelets. The effect of bovine serum albumin (BSA), dithiothreitol (DTT), divalent cations (Mg2+ and Ca2+), EDTA, and various chemicals on the activity of PAF-CPT of HMC was also studied. Moreover, preliminary in vitro tests have been performed with several anti-inflammatory factors such as drugs (simvastatin, IFNa, rupatadine, tinzaparin, and salicylic acid) and bioactive compounds of Mediterranean diet (resveratrol and lipids of olive oil, olive pomace, sea bass "Dicentrarchus labrax," and gilthead sea bream "Sparus aurata"). The results indicated that the above compounds can influence PAF-CPT activity of HMC.
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Affiliation(s)
- Alexandros Basilios Tsoupras
- Faculty of Chemistry, School of Sciences, National and Kapodistrian University of Athens, Panepistimioupolis, 15771 Athens, Greece
| | - Elizabeth Fragopoulou
- Department of Science of Dietetics and Nutrition, Harokopio University, 70 El. Venizelou Street, 176 71 Athens, Greece
| | - Tzortzis Nomikos
- Department of Science of Dietetics and Nutrition, Harokopio University, 70 El. Venizelou Street, 176 71 Athens, Greece
| | - Christos Iatrou
- Centre for Nephrology, G. Papadakis General Hospital of Nikea-Pireaus, 3 Mandouvalou Street, 18454 Athens, Greece
| | - Smaragdi Antonopoulou
- Department of Science of Dietetics and Nutrition, Harokopio University, 70 El. Venizelou Street, 176 71 Athens, Greece
| | - Constantinos Alexandros Demopoulos
- Faculty of Chemistry, School of Sciences, National and Kapodistrian University of Athens, Panepistimioupolis, 15771 Athens, Greece
- *Constantinos Alexandros Demopoulos:
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Zhang X, Pan XL, Liu XT, Wang S, Wang LJ. Down-regulation of platelet-activating factor receptor gene expression during focal reversible cerebral ischemia in rats. Neurochem Res 2007; 32:451-6. [PMID: 17268849 DOI: 10.1007/s11064-006-9248-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 12/01/2006] [Indexed: 11/28/2022]
Abstract
Platelet-activating factor (PAF) is an endogenous potent phospholipid mediator in stroke and related to the post-ischemic brain damage. The aim of this study was to investigate the regulation and mechanisms of PAF receptor gene expression in the perifocal regions of cerebral infarction after middle cerebral artery occlusion/reperfusion. Sixty mature Wistar rats were randomly divided into 12 groups: sham-operated control group, simple ischemia 90 min group, 6, 12, 18 h, 1 day (1 d), 2, 3, 4, 5, 6, 7 d reperfusion groups. After the right middle cerebral artery occluded, the rats were suffered from ischemia for 90 min, and then reperfusion was allowed for different time courses. Reverse transcription-polymerase chain reaction (RT-PCR) and radioimmunoassay were applied to evaluate the PAF receptor messenger RNA (mRNA) expression and PAF levels in the perifocal regions of cerebral infarction respectively. RT-PCR analysis revealed that PAF receptor mRNA was 0.95 +/- 0.15 in control group. However, following ischemia-reperfusion, the levels of PAF receptor mRNA progressively decreased until 2 d of reperfusion (0.54 +/- 0.10), then returned to control group's levels gradually. Compared with the control group's (582 +/- 72 pg/g wet weight), the PAF concentrations of simple ischemic and 6, 12, 18 h, 1, 2 d reperfusion group were significantly higher than that of any other groups. These results indicate that PAF receptor gene expression may be subject to down-regulation in the perifocal regions of cerebral infarction after cerebral ischemia-reperfusion and relative to the increase of endogenous PAF concentrations.
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Affiliation(s)
- Xiong Zhang
- Department of Neurology, Guangdong Provincial People's Hospital, Nanfang Medical University, 106, Zhongshan Er Road, Guangzhou, Guangdong Province 510080, PR China
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Heusler P, Boehmer G. Platelet-activating factor contributes to the induction of long-term potentiation in the rat somatosensory cortex in vitro. Brain Res 2007; 1135:85-91. [PMID: 17196945 DOI: 10.1016/j.brainres.2006.12.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Revised: 12/04/2006] [Accepted: 12/07/2006] [Indexed: 11/25/2022]
Abstract
The contribution of platelet-activating factor (PAF) to the induction of neocortical LTP was examined in rat brain slices containing the primary somatosensory cortex (SI). Field potentials evoked by single pulse stimulation in cortical layer IV were recorded from layer II/III. In control experiments, tetanic high frequency stimulation (HFS) resulted in input-specific, NMDA receptor-dependent LTP (21.1+/-3.2%; mean+/-SEM; n=15; P<0.001). BN-52021 (5 microM), an antagonist at the extracellular PAF receptor, weakened the HFS-induced LTP to 12.4+/-2.7% (n=11; P<0.05). In contrast, HFS-induced LTP was significantly enhanced to 29.4+/-2.3% (n=11; P<0.05) when brain slices were superfused with ACSF containing the PAF receptor-agonist C-PAF (1.5 microM). The difference between LTP weakened by BN-52021 and LTP enhanced by C-PAF was highly significant (P<0.0005). These results suggest a physiological contribution of PAF to the induction of LTP in neocortical area SI. This contribution of PAF is mediated by an action at extracellular receptor sites.
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Affiliation(s)
- Peter Heusler
- Institute of Physiology and Pathophysiology, Johannes Gutenberg University, Duesbergweg 6, D-55099 Mainz, Germany
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12
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Teather LA, Lee RKK, Wurtman RJ. Platelet-activating factor increases prostaglandin E(2) release from astrocyte-enriched cortical cell cultures. Brain Res 2002; 946:87-95. [PMID: 12133598 DOI: 10.1016/s0006-8993(02)02866-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The phospholipid mediator platelet-activating factor (PAF) increased the release of prostaglandin E(2) (PGE(2)) from astrocyte-enriched cortical cell cultures in a concentration- and time-dependent manner. The nonhydrolyzable PAF analog methylcarbamyl-PAF (mc-PAF), the PAF intermediate lyso-PAF, and arachidonic acid (AA) also produced this effect. In contrast, phosphatidlycholine (PC) and lyso-PC, lipids that are structurally similar to PAF and lyso-PAF, had no effect on PGE(2) production, suggesting that PAF-induced PGE(2) release is not the consequence of nonspecific phospholipid-induced membrane perturbation. Antagonism of intracellular PAF binding sites completely abolished the ability of mc-PAF and lyso-PAF to mobilize PGE(2,) and attenuated the AA effect. Antagonism of the G-protein-coupled PAF receptor in plasma membranes had no significant effect on mc-PAF, lyso-PAF or AA-induced PGE(2) release. Based on the present findings, we hypothesize that intracellular PAF is a physiologic stimulus of PGE(2) production in astrocytes.
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Affiliation(s)
- Lisa A Teather
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 45 Carleton Street, E25-604 Cambridge, MA 02139, USA.
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Abstract
Recovery of normal brain energetic conditions during and after resuscitation from cardiac arrest is critical for survival and good neurologic outcome. This review emphasizes the glucose-driven metabolic processes during and after ischemia and on the post-resuscitation development of secondary energy derangements. It also explores some potential therapeutic interventions designed to attenuate these energy derangements. The article summarizes some bench research and is not intended to provide treatment strategies for clinical application.
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Affiliation(s)
- U Ebmeyer
- University of Magdeburg, School of Medicine, Germany
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