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In vitro examination of anti-parasitic, anti-Alzheimer, insecticidal and cytotoxic potential of Ajuga bracteosa Wallich leaves extracts. Saudi J Biol Sci 2021; 28:3031-3036. [PMID: 34025179 PMCID: PMC8117137 DOI: 10.1016/j.sjbs.2021.02.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/29/2020] [Accepted: 02/10/2021] [Indexed: 11/13/2022] Open
Abstract
This research study is mainly focused to evaluate the anti-parasitic, insecticidal, cytotoxic and anti-alzheimer potential of various leaf extracts of Ajuga bracteosa Wallich ex Bentham. 04 different extracts were prepared using solvent of different polarity to determine the best candidate for potent bioactivity i.e. n-hexane (NH), Ethyl acetate (EA), Ethanol (EL) and Chloroform (CH). Concentrations of each extracts were made specified for all activities. All extracts were exploited for broad range of biomedical applications including leishmaniasis, in vitro anti-Alzheimer, insecticidal and cytotoxic studies. Our results showed that A. bracteosa n-hexane extract was highly active against Leishmania Tropica with significant inhibition of 58 ± 1.61 for promastigote and 63 ± 2.29 for amastigote at 1000 μg/mL. Furthermore, promising anti-alzheimer activity acetylcholinesterase (AChE) 46 ± 0.83 and butrylcholineterase (BChE) 49 ± 1.17 was noted for n-hexane. The insecticidal potential of these extracts were test against five different insects (Rhyzopertha dominica, Trogoderma granarium, Tribolium castaneum, Sitophilus oryze, and Callosobruchus analis). The higest mortality rate of insecticidal activity was recorded by n-hexane followed by Ethyl acetate whereas ethanol extract was found to be less effective against all the test species. Significant cytotoxic potential of each plant sample against Artemia salina thus aware us for further detailed research to find out novel drugs. Based on our results we believe that Ajuga bracteosa could be used to develop as a potential botanical insecticide against different insect and pests, such as aphids as well as an excellent source for the compound isolation as anti-tumor agent.
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Green Synthesis of Zinc Oxide (ZnO) Nanoparticles Using Aqueous Fruit Extracts of Myristica fragrans: Their Characterizations and Biological and Environmental Applications. ACS OMEGA 2021; 6:9709-9722. [PMID: 33869951 PMCID: PMC8047667 DOI: 10.1021/acsomega.1c00310] [Citation(s) in RCA: 150] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/15/2021] [Indexed: 06/28/2023]
Abstract
In the present work, bioaugmented zinc oxide nanoparticles (ZnO-NPs) were prepared from aqueous fruit extracts of Myristica fragrans. The ZnO-NPs were characterized by different techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet (UV) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and thermogravimetric analysis (TGA). The crystallites exhibited a mean size of 41.23 nm measured via XRD and were highly pure, while SEM and TEM analyses of synthesized NPs confirmed their spherical or elliptical shape. The functional groups responsible for stabilizing and capping of ZnO-NPs were confirmed using FTIR analysis. The ζ-size and ζ-potential of synthesized ZnO-NPs were reported as 66 nm and -22.1 mV, respectively, via the DLS technique can be considered as moderate stable colloidal solution. Synthesized NPs were used to evaluate for their possible antibacterial, antidiabetic, antioxidant, antiparasitic, and larvicidal properties. The NPs were found to be highly active against bacterial strains both coated with antibiotics and alone. Klebsiella pneumoniae was found to be the most sensitive strain against NPs (27 ± 1.73) and against NPs coated with imipinem (26 ± 1.5). ZnO-NPs displayed outstanding inhibitory potential against enzymes protein kinase (12.23 ± 0.42), α-amylase (73.23 ± 0.42), and α-glucosidase (65.21 ± 0.49). Overall, the synthesized NPs have shown significant larvicidal activity (77.3 ± 1.8) against Aedes aegypti, the mosquitoes involved in the transmission of dengue fever. Similarly, tremendous leishmanicidal activity was also observed against both the promastigote (71.50 ± 0.70) and amastigote (61.41 ± 0.71) forms of the parasite. The biosynthesized NPs were found to be excellent antioxidant and biocompatible nanomaterials. Biosynthesized ZnO-NPs were also used as photocatalytic agents, resulting in 88% degradation of methylene blue dye in 140 min. Owing to their eco-friendly synthesis, nontoxicity, and biocompatible nature, ZnO-NPs synthesized from M. fragrans can be exploited as potential candidates for biomedical and environmental applications.
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Edible mushroom (Flammulina velutipes) as biosource for silver nanoparticles: from synthesis to diverse biomedical and environmental applications. NANOTECHNOLOGY 2021; 32:065101. [PMID: 33119546 DOI: 10.1088/1361-6528/abc2eb] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The current study reports advanced, ecofriendly and biosynthesized silver NPs for diverse biomedical and environmental applications using Flammulina velutipes as biosource. In the study, a simple aqueous extract of F. velutipes was utilized to reduce the AgNO3 into stable elemental silver (Ag0) at a nanometric scale. The NPs had average size of 21.4 nm, spherical morphology, and were highly stable and pure. The characterized nanoparticles were exploited for a broad range of biomedical applications including bacteriocidal, fungicidal, leishmanicidal, in vitro antialzheimer's, antioxidant, anti-diabetic and biocompatibility studies. Our findings showed that F. velutipes mediated AgNPs exhibited high activity against MDR bacterial strains and spore forming fungal strains. All the tested urinary tract infection bacterial isolates, were resistant to non-coated antibiotics but by applying 1% of the synthesized AgNPs, the bactericidal potential of the tested antibiotics enhanced manifolds. The NPs also exhibited dose-dependent cytotoxic potential against Leishmania tropica with significant LC50 of 248 μg ml-1 for promastigote and 251 μg ml-1 for amastigote forms of the parasite. Furthermore, promising antialzheimer and antidiabetic activities were observed as significant inhibition of α-amylase, α-glucosidase, acetylcholinesterase (AChE) and butrylcholineterase (BChE) were noted. Moreover, remarkable biocompatible nature of the particles was found against human red blood cells. The biosynthesized AgNPs as photocatalyst, also resulted in 98.2% degradation of indigo carmine dye within 140 min. Owing to ecofriendly synthesis, biosafe nature and excellent physicochemical properties F. velutipes AgNPs can be exploited as novel candidates for multifaceted biomedical and environmental applications.
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Covid-19 And Co-Infections: An Overview Of Ace2 Mediated Viral Entry Of Sars-Cov-2 And Multiorgan Failure In Covid-19. INTERNATIONAL CARDIOVASCULAR FORUM JOURNAL 2020. [DOI: 10.17987/icfj.v20i0.693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
COVID-19 is highly fatal disease having high mortality rate and is declared as pandemic situation by world health organization. It shows a clear indication that every individual is at risk of this pandemic especially older individual and immunocompromised persons. As its casual agent is SARS-Cov-2 and the main target site of this virus is the ACE2 receptor of lungs. But as compared to lungs ACE2 receptor is highly expressed in other organs i.e. kidney, liver, brain, GI tract, cutaneous, adipose tissues and cardiovascular system these organs are susceptible to COVID-19 infections because of having ACE2 receptor. Many co-infections associated with COVID-19 are reported i.e. neurological manifestation of COVID-19, cutaneous manifestations of COVID-19, endothelial cell infection and endotheliitis, adipose tissues infections, cerebral hemorrhage, liver injury, cardiovascular complications, kidney infection, trigger immune system response and subsequent organ failure. In this review we highlight ACE2 mediated viral entry of the SARS-Cov-2 and subsequent multi organ failure in COVID-19.
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In Vitro Biomedical and Photo-Catalytic Application of Bio-Inspired Zingiber officinale Mediated Silver Nanoparticles. J Biomed Nanotechnol 2020; 16:492-504. [PMID: 32970981 DOI: 10.1166/jbn.2020.2918] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To minimize the hazardous effect of physical and chemical synthesis of nanoparticles we focused on the green synthesis of nanoparticles. Nanotechnology is a research hotspot and catch great attention because of its versatile applications in medical, biosciences and engineering fields. Purpose of our recent study is to synthesize bio-inspired metallic silver NPs by root mediated Zingiber officianale extract. The synthesized Ag-NPs were further characterized by using UVVisible spectroscopy, XRD, EDX, SEM, TEM and DLS techniques. The extent of crystallites were confirmed by X-ray diffraction. SEM and TEM revealed the morphological features with size of nanoparticles between 17.3 and 41.2 nm. FTIR analysis confirmed the capping of nanoparticles by bio active constituents present in Zingiber officinale extract. Later EDX confirmed the elemental composition of nanoparticles. Zeta potential, PDI and hydrodynamic size of Ag-NPs were confirmed by DLS. The synthesize Ag-NPs possess eminent biological potency against bacterial and leishmanial strains. Moreover considerable anti-diabetic, anticancer, antioxidant and biocompatibility nature of Ag-NPs was elucidated. The highest antioxidant activity of 50.61± 1.12%, 38.22 ± 1.18% and 27.39 ± 0.92 at 200 g/mL for TAC, TRP DPPH and was observed respectively. Ag-NPs exhibit potent leishmanicidal activity of 80% ± 1.4 against promastigotes and 77% ± 1.6 against amastigotes cultures of L. tropica. Highest antidiabetic activity 30 ± 0.77% recorded at 200 μg/ml. Highest Brine shrimps cytotoxicity of Ag-NPs was 60 ± 1.18 at 200 g/ml. Maximum dye degradation for Ag-NPs was recorded as 94.1% at 140 minute. All UTI isolates were resistant to antibiotics not coated with Ag-NPs. By applying 1% of Ag-NPs highest activity was recorded as 25 ± 1.58 mm against K. pneumoniae. Maximum zone of inhibition for Ag-NPs coated with Imipenem antibiotics 26 ± 1.5 mm against K. pneumoniae and coated with Ciprofloxacin 26 ± 1.4 m against S. aureus were measured. Last but not least high biocompatible nature of Ag-NPs was observed against fresh RBCs making the ecofriendly biosynthesized silver NPs a multi-dimensional candidate in biomedical field.
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Drug resistance pattern in Mycobacterium tuberculosis to the first line drugs of pulmonary tuberculosis patients at Hazara Region, Pakistan. Tuberk Toraks 2018; 66:26-31. [PMID: 30020038 DOI: 10.5578/tt.60781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Introduction Multidrug resistant TB (MDR-TB), defined as resistance to at least rifampicin and isoniazid together, has been rapidly spreading in recent years. In new pulmonary tuberculosis patients, rapid spread of MDR-TB and XDR-TB challenging the effectiveness of national TB control programs especially in many low-income countries. This study was aimed to determine the resistance pattern of Mycobacterium tuberculosis among new cases, cured, failure, relapse, defaulted, treatment completed, treatment not evaluated and suspect to be resistant to first line antitubercular drugs of pulmonary tuberculosis (PTB). Materials and Methods The study was conducted during 2013-2016 in which 148 patients were enrolled infected with pulmonary TB. Three sputum samples were consecutively collected and transported for drug analysis to the Provincial Reference Laboratory (PRL) at Hayatabad Medical complex Peshawar (HMCP) TB laboratory, within three days of collection at +4°C in a cold box. Using the standard proportion method, drug susceptibility test was performed on 132 (89.2%) sputum samples for rifampicin (R), isoniazid (H), pyrazinamide (Z), ethambutol (E), and streptomycin (S). Result Prevalence of resistance to one drug was 5 (3.4%). The highest proportion of mono-drug resistance was observed against E, 3 (2%), followed by H, 1 (0.7%), and R, 1 (0.7%). Pattern of resistant to two drugs was 14 (9.5%). The proportion of poly resistant was 3 (2%). 112 (93.33%) diagnose patients were MDR-TB. Conclusions To formulate an effective regimen, it is important to know drug resistant pattern because drug resistant pattern varies from different period of time also from one place to another.
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Abstract
BACKGROUND The first Irish heart transplant was performed on the 10th of September 1985. Over the next 20 years, 229 transplants were performed in 228 recipients. AIMS To evaluate the success of the first generation of cardiac transplantation in Ireland. METHODS Analysis of clinical outcomes and survival statistics for patients undergoing heart transplantation in Ireland and comparison with international standards. RESULTS There has been a steady improvement in transplant outcome over this time and survival figures for recipients between 2000 and 2004 show a hospital, 1-year and 5-year survival rate of 85.7%, 84.1% and 76.8% respectively. Thirty-eight of the 99 heart transplants performed between 1985 and 1994 are still alive more than 10 years later and the longest survivor is now 19 years post transplantation. CONCLUSIONS The results compare favourably with international figures. Heart transplantation offers excellent longterm survival and quality of life but remains challenged by a shortage of suitable donor organs.
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Traumatic rupture of the aorta in an 11-year-old patient: Surgical considerations in the technique of repair. Surgeon 2005; 3:95-7. [PMID: 15861944 DOI: 10.1016/s1479-666x(05)80069-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We describe an 11-year-old child who presented with a traumatic aortic transection. This is an extremely rare occurrence in this age group. In managing the injury the future growth of the child must be considered. Primary repair is ideal when possible, but in choosing a graft, the choice of size and material should take cognisance of the risk of a coarctation-like syndrome in the future.
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Complications of in-dwelling venous access devices: a single institution experience. J PAK MED ASSOC 2001; 51:434-7. [PMID: 11850980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To determine the complications of venous access devices (VADs) in cancer patients. SETTING Retrospective study in a tertiary referral center with specialist hematology and oncology services. SUBJECTS First one hundred consecutive patients who were implanted a VAD. All patients had an underlying cancer and the devices were inserted by the same surgeon. The duration of use of VADs and causes of their premature removal were noted. RESULTS One hundred VADs (55 port-a-caths and 45 Hickman's lines) were inserted in a total of 89 patients over a 7.5 year period. Majority of patients had acute myeloid leukemia (22) gastrointestinal malignancies (20) breast cancer (19) and genito-urinary cancers (15). The mean duration of use was 110 days; 157 days for the port-a-cath and 53 days for the Hickman's line. Nineteen devices (10 port-a-caths and 9 Hickman's lines) had to be removed prematurely. Two Hickman's lines got removed accidentally. The causes of premature removal included device failure (9), exist site infection (4), luminal infection (3) and tunnel infection (3). CONCLUSION The mean duration of use and the complication rates are comparable with studies reported in the literature.
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Heat shock protein 27 shows a distinctive widespread spatial and temporal pattern of induction in CNS glial and neuronal cells compared to heat shock protein 70 and caspase 3 following kainate administration. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2001; 93:148-63. [PMID: 11589992 DOI: 10.1016/s0169-328x(01)00199-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Kainate-induced status epilepticus is associated with both apoptotic and necrotic cell death and induction of heat shock proteins (HSPs) in hippocampal and cortical regions of the rodent brain. In the present study we have examined the temporal, spatial and cellular expression patterns of mRNAs for the highly inducible HSPs, HSP70 and HSP27, together with the apoptotic marker, caspase 3 (CPP32) in rat brain after systemic administration of kainate. HSP70 mRNA was transiently induced in the forebrain by kainate, principally in the CA1, CA3 and hilar cells of the hippocampal formation, in piriform cortex and discrete thalamic nuclei. Maximal expression was seen at 8 h after kainate which then declined to background levels by 7 days. Labelling was predominantly neuronal. In contrast, HSP27 mRNA expression was more widespread. Intense labelling was observed in CA1, CA3 and the hilar region at 8 h after kainate but the expression profile for HSP27 mRNA expanded considerably with intense signals seen in corpus callosum, cortex and thalamus at 24 h post kainate. Emulsion autoradiographs indicated a predominantly glial localisation for HSP27 mRNA. In the hilus, a distinct subpopulation of interneurones were found to express HSP27 mRNA. CPP32 mRNA was upregulated in CA1, CA3 and hilus of the hippocampal formation and in piriform cortex. CPP32 mRNA expression was more restricted and similar in distribution to HSP70 mRNA being localised to neurones. The present study demonstrates the unique early expression of HSP27 mRNA by glial cells and distinct populations of neurones which extends beyond those in which HSP70 and CPP32 induction occurs with subsequent cell loss.
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Abstract
Glutamate, the principal excitatory neurotransmitter in the brain, acts on three families of ionotropic receptor--AMPA (alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid), kainate and NMDA (N-methyl-D-aspartate) receptors and three families of metabotropic receptor (Group I: mGlu1 and mGlu5; Group II: mGlu2 and mGlu3; Group III: mGlu4, mGlu6, mGlu7 and mGlu8). Glutamate is removed from the synaptic cleft and the extracellular space by Na+-dependent transporters (GLAST/EAAT1, GLT/EAAT2, EAAC/EAAT3, EAAT4, EAAT5). In rodents, genetic manipulations relating to the expression or function of glutamate receptor proteins can induce epilepsy syndromes or raise seizure threshold. Decreased expression of glutamate transporters (EAAC knockdown, GLT knockout) can lead to seizures. In acquired epilepsy syndromes, a wide variety of changes in receptors and transporters have been described. Electrically-induced kindling in the rat is associated with functional potentiation of NMDA receptor-mediated responses at various limbic sites. Group I metabotropic responses are enhanced in the amygdala. To date, no genetic epilepsy in man has been identified in which the primary genetic defect involves glutamate receptors or transporters. Changes are found in some acquired syndromes, including enhanced NMDA receptor responses in dentate granule cells in patients with hippocampal sclerosis.
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Reduction of GABA and glutamate transporter messenger RNAs in the severe-seizure genetically epilepsy-prone rat. Neuroscience 1998; 85:1235-51. [PMID: 9681960 DOI: 10.1016/s0306-4522(97)00684-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The genetically epilepsy-prone rat is an animal model of inherited generalised tonic-clonic epilepsy that shows abnormal susceptibility to audiogenic seizures and a lowered threshold to a variety of seizure-inducing stimuli. Recent studies suggest a crucial role for glutamate and GABA transporters in epileptogenesis and seizure propagation. The present study examines the levels of expression of the messenger RNAs encoding the glial and neuronal glutamate transporters, GLT-1 and EAAC-1, and the neuronal GABA transporter, GAT-1, in paired male genetically epileptic-prone rats and Sprague Dawley control rats using the technique of in situ hybridization. In a parallel study, semiquantitative immunoblotting was used to assess GLT-1 and EAAC-1 protein levels in similarly paired animals. Animals were assessed for susceptibility to audiogenic seizures on six occasions, and killed seven days following the last audiogenic stimulus exposure. Rat brains were processed for in situ hybridization with radioactive 35S-labelled oligonucleotide probes (EAAC-1 and GAT-1), 35S-labelled riboprobes (GLT-1), and Fluorescein-labelled riboprobes (GLT-1 and GAT-1) or processed for immunoblotting using subtype-specific antibodies for GLT-1 and EAAC-1. Semiquantitative analyses were carried out on X-ray film autoradiograms in several brain regions for both in situ hybridization and immunoblotting studies. Reductions in GAT-1 messenger RNA were found in genetically epileptic-prone rats in all brain regions examined (-8 to -24% compared to control). Similar reductions in GLT-1 messenger RNA expression levels were seen in cortex, striatum, and CA1 (-8 to -12%) of genetically epileptic-prone rats; the largest reduction observed was in the inferior colliculus (-20%). There was a tendency for a reduced expression of EAAC-1 messenger RNA in most regions of the genetically epileptic-prone rat brain although this reached statistical significance only in the striatum (-12%). In contrast, no significant differences in GLT-1 and EAAC-1 protein between genetically epileptic-prone rats and control animals were observed in any region examined, although there was a tendency to follow the changes seen with the corresponding messenger RNAs. These results show differences in the messenger RNA expression levels of three crucial amino acid transporters. For the two glutamate transporters, GLT-1 and EAAC-1, differences in messenger RNA levels are not reflected or are only partially reflected in the expression of the corresponding proteins.
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Expression of glial glutamate transporters GLT-1 and GLAST is unchanged in the hippocampus in fully kindled rats. Neuroscience 1997; 78:351-9. [PMID: 9145792 DOI: 10.1016/s0306-4522(96)00570-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In situ hybridization techniques and quantitative western blotting were used to study the expression of the glial glutamate transporter GLT-1 and GLAST in the brains of normal (implanted, non-kindled) and fully kindled rats. Wistar rats were implanted with stimulating electrodes in the basolateral amygdala, and killed 28 days after the stimulated group had shown stage 5 seizures on five occasions. The brains were processed for in situ hybridization of messenger RNA for GLT-1 using 35S-labelled oligonucleotide probes or digoxigenin-labelled riboprobes. Paired (kindled and non-kindled) sections were used for qualitative and quantitative analyses. Image analysis of autoradiograms showed no change in expression of GLT-1 messenger RNA in any region of the hippocampus or in the cortex. An increase in expression of GLT-1 messenger RNA (expressed as percentage difference of control) was observed bilaterally in the striatum in kindled animals (16-21%, P<0.05). Nuclear emulsion-dipped sections showed predominant glial cell labelling in the hippocampus. Particle density analysis revealed reduced cell labelling in some kindled vs control pairs but overall there was no significant reduction in labelling in CA1. Equivalent results were found in CA1 using digoxigenin-labelled riboprobes. Quantitative immunoblotting also revealed no change in GLT-1 or GLAST transporter protein in the hippocampus of kindled animals. From these data we conclude that the enduring seizure susceptibility associated with the fully kindled state is unlikely to involve alterations in hippocampal GLT-1 messenger RNA or GLT-1 and GLAST transporter protein expression.
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Altered expression of group I metabotropic glutamate receptors in the hippocampus of amygdala-kindled rats. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1996; 43:105-16. [PMID: 9037524 DOI: 10.1016/s0169-328x(96)00162-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Kindling is a well documented model of acquired focal epilepsy and synaptic plasticity in the nervous system. Previous biochemical studies have indicated an increase in mGluR-mediated phosphoinositide hydrolysis in the amygdala or hippocampus of fully kindled animals. In this study we have used in situ hybridisation techniques to examine the mRNA expression of group I metabotropic glutamate receptors (mGluR1 and mGluR5 both linked to phosphoinositide hydrolysis) in the hippocampus of amygdala-kindled animals sacrificed 24 h, 7 days or 28 days following the last electrically evoked stage 5 seizure, and in implanted non-stimulated control rats. Results indicate an initial up-regulation in mGluR1 mRNA (expressed as percentage of control) bilaterally in the DG (35-40%) and CA3 (16-48%), and unilaterally in CA4 (12%) in the 24 h post-kindled group. In kindled animals studied 7 days after the last seizure, these changes were either reduced or had returned to control levels. By 28 days mGluR1 mRNA levels had returned to control levels, with only a persistent increase in expression unilaterally in the DG (14%). In contrast, an initial down-regulation in mGluR5 mRNA was observed bilaterally in CA4 (-45 and -25%) and CA1 (-46 and -45%), and unilaterally in DG and CA3 (-27 and -42% respectively) 24 h after the last kindled seizure. In the 7 and 28 day kindled groups significant alterations in expression of mGluR5 mRNA were still apparent. These data show that the mRNAs for mGluR1 and mGluR5 are differentially regulated by kindling, indicating that the expression of each of these receptors is under independent regulatory control. These perturbations in mRNA expression may contribute to kindling epileptogenesis but are unlikely to account for the maintenance of the kindled state.
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Abstract
1. The repeated co-administration of the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (0.1 and 0.3 mg kg-1, i.p.) with nicotine (0.4 mg kg-1, s.c.) attenuated the development of tolerance to the locomotor depressant effect of the nicotine in rats. 2. The repeated co-administration of the competitive NMDA antagonist D-CPPene (SDZ EAA 494; 3-(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphonic acid, 2 and 8 mg kg-1, i.p.) also attenuated tolerance to the locomotor depressant effect of nicotine. 3. Dizocilpine (0.3 mg kg-1, i.p.) pretreatment attenuated sensitization to the locomotor stimulant effect of nicotine (0.4 mg kg-1, s.c.) and prevented sensitization of nicotine-induced dopamine release in the nucleus accumbens. However, pretreatment with dizocilpine alone caused a modest enhancement of the behavioural response to a subsequent acute dose of nicotine. 4. D-CPPene (2.0 mg kg-1, i.p.) pretreatment prevented sensitization to the nicotine-induced dopamine release in the nucleus accumbens. There was no enhanced locomotor response that could be attributed to nicotine pretreatment when D-CPPene was co-administered with nicotine. However, pretreatment with D-CPPene alone enhanced the locomotor response to an acute dose of nicotine. 5. The results suggest the involvement of NMDA receptors in adaptations of the behavioural and neurochemical effects of nicotine that occur as a result of repeated administration of the drug.
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