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1.
Bioresour Technol ; 369: 128219, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36343777

RESUMEN

Microbial cellulases are the enzymes used in numerous industrial biotechnological applications. Efficiency of celluloytic cocktails plays a key role in the conversion of biomass into biofuels, but limited production, high cost and low efficiency are the main obstacles to sustainable biorefining. The current work aims to establish a feasible approach for boosting the production of fungal endoglucanse (EG) and its functional stability utilizing nanocomposite materials based on manganese oxide. Herein, aqueous extract from mixed fruit waste was used to synthesize the nanocomposite sample, which was subsequently subjected to several characterization techniques for analysis. Following the solid-state fermentation of paddy straw, and by employing 75 mg nanocomposite, 192 IU/gds EG was produced under the optimal conditions, while 19 IU/gds FP and 98 IU/gds BGL production were recorded. The crude EG enzyme treated with nanocomposite also shows complete stability at pH 5.0 for 3.5 h while retaining thermal activity at 70 °C for 4 h.


Asunto(s)
Celulasas , Frutas , Porosidad , Óxidos , Fermentación
2.
Ayu ; 31(4): 488-94, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22048545

RESUMEN

Apabahuka is a disease that usually affects the Amsa sandhi (shoulder joint).It is produced by the Vata dosha. Even though the term Apabahuka is not mentioned in the nanatmaja Vata vyadhi, Acharya Sushruta and others have considered Apabahuka as a Vataja vikara. Amsa shosha (wasting of the shoulder) can be considered as the preliminary stage of the disease, where loss or dryness of sleshaka kapha from amsa sandhi occurs. For the present study, Marsha nasya with Laghumasa Taila was administered to 15 patients for seven days, and the following results were obtained. After treatment, 53.33% relief was found on Bahupraspandita hara, 26.66% on Shoola, 30.00% on Stambha, 60.00% on Atopa, and 37.50% on wasting of muscles. On the overall effect of therapy alone, one (6.60%) patient got marked improvement, eight (53.33%) got moderate improvement, four (26.66%) were improved, and two (13.33%) patients remained unchanged.

3.
Afr J Paediatr Surg ; 5(2): 65-70, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-19858669

RESUMEN

BACKGROUND: Ascariasis is the infestation by the largest intestinal nematode of man, a common problem in the tropics attributed to poor hygienic and low socioeconomic conditions. The aim of this research is to analyse the presentation, diagnosis and management of bowel obstruction caused by Ascaris lumbricoides, with special emphasis on the role of conservative management. MATERIALS AND METHODS: This is a single centre, two consultant based 5 year retrospective study of childhood intestinal obstruction due to worms. Diagnosis in the suspected patients was based on history of passage of worms per mouth or rectum and on x-ray and ultrasonography findings. Only the patients of intestinal obstruction with documented evidence of roundworm infestation were included in the study and were followed for one year. RESULTS: One hundred and three children with intestinal obstruction due to Ascaris lumbricoides were treated in the past five years at our centre. Abdominal pain was the most common presentation seen in 96 children followed by vomiting in 77 children. 20 children had history of vomiting worms and another 43 had history of passing worms in stool. Abdominal tenderness was present in 50 children, 48 had abdominal distension of varying degree, 50 had abdominal mass due to worm bolus, and 16 had or developed abdominal guarding or rigidity. All the children were managed as for acute intestinal obstruction along with hypertonic saline enema. The aim of management was "to starve the worm and hydrate the patient". 87 patients (84.47%) responded favourably and were relieved of the obstruction by the conservative management, 16 children (15.53%) had abdominal guarding or rigidity and underwent emergency exploration. CONCLUSION: Roundworm obstruction should be considered in the differential diagnoses of all cases of intestinal obstruction in children. Clinical history and examination along with X-ray and ultrasonography are very helpful for diagnosis of this surgical emergency. Most cases of intestinal obstruction due to Ascaris can be managed conservatively; however emergency surgery is needed in patients with abdominal guarding and rigidity.

4.
Brain Res ; 1033(1): 1-12, 2005 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-15680333

RESUMEN

This study records noise-free intracerebral EEG of the genetically epilepsy prone rat (GEPR-9), along with behavioral correlates, during a seizure on unanesthetized freely behaving unrestrained animals. The GEPR-9 exhibits acoustically triggered generalized tonic-clonic seizures, and often times the EEG, recorded with conventional techniques, has resulted in data with imbedded movement artifact. For noise-free video-EEG recordings, we used a previously developed system that consists of a head connector with a FET preamplifier and battery, signal conditioning device (5000x gain, 1 Hz-100 Hz filters), A/D converter and video/PC-PC/video computer boards for recording image data. Each animal was implanted with three monopolar/referential electrodes chosen among the following areas: cortex, inferior colliculus, reticular formation and caudal medulla. The video-EEG data were quite similar for all recorded animals: (1) basal desynchronized EEG before sound stimulus; (2) increase in EEG frequency after stimulus and before seizure onset; (3) high-amplitude polyspikes during massive myoclonic thrusts with or without a very fast running episode; (4) an electrodecremental response during tonic extension; (5) wave and spike complex during forelimb and hindlimb tonic rigidity and posttonic clonus; (6) low-amplitude EEG during postictal depression. Time sequenced spectral analysis also highlights the epileptiform EEG pattern during seizure with high reproducibility between animals. While testing seizure naive GEPR-9s, there was a clear evolution from modest epileptiform EEG activity on the first acoustic stimulation to progressively higher amplitude, duration and frequency epileptiform EEG activity throughout seizure repetition.


Asunto(s)
Conducta Animal/fisiología , Electroencefalografía/métodos , Epilepsia Tónico-Clónica/fisiopatología , Predisposición Genética a la Enfermedad , Estimulación Acústica/efectos adversos , Animales , Anticonvulsivantes/uso terapéutico , Conducta Animal/efectos de los fármacos , Mapeo Encefálico , Carbamazepina/uso terapéutico , Modelos Animales de Enfermedad , Electrodos , Electroencefalografía/efectos de los fármacos , Epilepsia Tónico-Clónica/tratamiento farmacológico , Epilepsia Tónico-Clónica/genética , Análisis de Fourier , Lateralidad Funcional , Ratas , Ratas Mutantes , Ratas Sprague-Dawley , Análisis Espectral , Factores de Tiempo , Grabación en Video/métodos
5.
Phytother Res ; 18(4): 285-9, 2004 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15162362

RESUMEN

The benzene chromatographic fraction of the chloroform extract of the seeds of Carica papaya at a dose of 10 mg/rat/day for 150 days, which has shown a total inhibition of motility, reduced sperm count and infertility, was tested to de fi ne the mode of action at the subcellular level in the testis and epididymis. The ultrastructure of the testis of the treated animals revealed no appreciable changes in the subcellular characteristics. The mechanism of protein synthesis as well as steroidogenesis were evident in the Sertoli cells while the spermatogonia, spermatocytes and spermatids, both round and elongated, depicted a prominent nucleus, distinct nuclear membrane and cytoplasmic characteristics indicating normal germ cell differentiation. The principal cells of the cauda epididymis were characterized by the presence of well-de fi ned rough endoplasmic reticulum, mitochondria, Golgi bodies and secretary granules, suggesting active secretory functions. The absorptive function of the cauda epididymis was evidenced by the presence of numerous vesicles and multivesicular bodies adjacent to stereocilia. It is concluded that the inhibition of sperm motility by the drug could be due to other epididymal factors rather than the subcellular characteristics of testis and epididymis.


Asunto(s)
Carica , Fitoterapia , Extractos Vegetales/farmacología , Testículo/efectos de los fármacos , Animales , Epidídimo/efectos de los fármacos , Epidídimo/ultraestructura , Masculino , Extractos Vegetales/administración & dosificación , Extractos Vegetales/uso terapéutico , Ratas , Ratas Wistar , Semillas , Testículo/ultraestructura
6.
Asian J Androl ; 4(1): 17-26, 2002 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11907624

RESUMEN

AIM: To evaluate the antifertility activity of the chloroform extract of Carica papaya seeds by oral administration in langur monkey, Presbytis entellus entellus. METHODS: The chloroform extract of Carica papaya seeds, 50 mg/kg/day, was administered orally for 360 days to adult male langur monkeys. The sperm characteristics by light and electron microscopy, the sperm functional tests, the semen biochemistry, the serum testosterone level, the Leydig cell function, and the histology and ultrastructure of testis were determined to evaluate the antifertility activity and the blood biochemistry and hematology, to evaluate the toxicology. RESULTS: The extract gradually decreased the sperm concentration since days 30-60 of treatment with a total inhibition of sperm motility, a decrease in sperm viability and increase in sperm abnormality. Azoospermia was observed after day 90 of treatment and continued during the whole treatment period. Treatment withdrawal resulted in a gradual recovery in these parameters and 150 days later they reverted to nearly the pretreatment values. Morphological observation of the ejaculated sperm by light and scanning electron microscopy showed deleterious changes, particularly on the mid-piece. Sperm functional tests, viz., sperm mitochondrial activity index, acrosome intactness test and hypo-osmotic swelling test scored in the infertile range during treatment and returned to the fertile values 150 days after drug withdrawal. Histology of the testis revealed shrunken tubules, germ cell atrophy and normal Leydig cells. Ultrastructure of the testis showed vacuolization in the cytoplasm of Sertoli cells and germ cells. Loss of cytoplasmic organelles were evident in the spermatocytes and spermatids. Round spermatids showed loss of Golgi bodies, peripheral mitochondria and vacuolated cytoplasm, indicating maturational arrest. Leydig cell functional test indicated a mild inhibition of steroidogenic function. Haematology and serum biochemistry study disclosed no significant toxicological effect and the serum testosterone level was not affected. CONCLUSION: Carica papaya seed extract may selectively act on the developing germ cells, possibly mediated via Sertoli cells, leading to azoospermia.


Asunto(s)
Carica , Anticonceptivos Masculinos/farmacología , Oligospermia/inducido químicamente , Extractos Vegetales/farmacología , Animales , Cercopithecidae , Cloroformo , Eyaculación/efectos de los fármacos , Masculino , Microscopía Electrónica , Semen/química , Semen/efectos de los fármacos , Células de Sertoli/efectos de los fármacos , Células de Sertoli/ultraestructura , Solventes , Recuento de Espermatozoides , Espermatozoides/citología , Espermatozoides/efectos de los fármacos , Testosterona/sangre
7.
Indian J Biochem Biophys ; 39(6): 406-9, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22905399

RESUMEN

Omeprazole and lansoprazole, the therapeutically important drugs belonging to proton pump inhibitor category are extensively used in the treatment of gastric ulcers. Transport through liquid membranes generated by these drugs in lecithin-cholesterol mixture in series with a supporting membrane has been studied. The data obtained show the formation of liquid membrane in series with the supporting membrane. Transport of cations, chloride and bicarbonate ions in the presence liquid membranes generated by omeprazole and lanzoprazole indicate the modification in the permeability of various permeants.


Asunto(s)
2-Piridinilmetilsulfinilbencimidazoles/química , Membranas Artificiales , Omeprazol/química , Bicarbonatos/química , Bioquímica/métodos , Cationes , Química Farmacéutica/métodos , Cloruros/química , Colesterol/química , Diseño de Fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Concentración de Iones de Hidrógeno , Iones , Lansoprazol , Lecitinas/química , Modelos Biológicos , Modelos Químicos , Conformación Molecular , Permeabilidad
8.
Phytomedicine ; 7(4): 325-33, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10969727

RESUMEN

The contraceptive effects of benzene chromatographic fraction of the chloroform extract of the seeds of Carica papaya have been reported in male albino rats at the dose regimens 5 and 10 mg/animal/day; oral for 150 days. The body weight, weight of testis, epididymis, seminal vesicle and ventral prostate remained unaltered during the entire course of the investigation. Total suppression of cauda epididymal sperm motility coincided with a decrease in sperm count, viability and an increase in per cent abnormal spermatozoa during 60-150 days observation period. Minor changes in the germ cell proliferations in the testis and vacuolization and pyknotic nuclei in the few epithelial cells of the cauda epididymis were observed. Histology and biochemical composition of testis and accessory sex organs, haematology and serum clinical biochemistry and serum testosterone levels remained unchanged throughout the course of the investigation. Test for estrogenicity indicated mild estrogenicity. Monthly fertility test showed negative fertility. All the altered parameters returned to normal level following 60 days withdrawal of the treatment. The results suggest that the benzene chromatographic fraction of the chloroform extract of the seeds of Carica papaya exerts antifertility effects in rats without adverse toxicity and that the effects may be directly rendered on the spermatozoa.


Asunto(s)
Anticonceptivos Masculinos/farmacología , Extractos Vegetales/farmacología , Rosales , Semillas , Motilidad Espermática/efectos de los fármacos , Administración Oral , Animales , Anticonceptivos Masculinos/administración & dosificación , Anticonceptivos Masculinos/química , Masculino , Extractos Vegetales/administración & dosificación , Extractos Vegetales/química , Plantas Medicinales , Ratas , Ratas Wistar , Testículo/efectos de los fármacos
9.
J Ethnopharmacol ; 70(1): 17-27, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10720785

RESUMEN

The contraceptive evaluation and toxicological effects of the aqueous extract of the seeds of Carica papaya in adult male rabbits have been reported. Thirty adult male rabbits were divided into five groups of six animals each; Group I, control; Groups II-V were administered orally with aqueous extract of the seeds of C. papaya at doses of 20, 50, 75 and 100 mg/kg per day for 150 days, respectively. The body weight, reproductive organs weight, semen analysis, semen biochemistry, toxicological profiles and the fertility status have been recorded. The aqueous extract failed to exhibit contraceptive effects at any of the dose regimens tested, contrary to the observations made in the previous studies. Unaltered toxicological profiles indicated that the drug was free of side effects. The results suggest that the failure of contraceptive effects may be due to species specificity, relative resistance of the animals to the drug or lack of potency of the extract due to factors generally affect biological activity of the plant preparations.


Asunto(s)
Anticonceptivos Masculinos/farmacología , Extractos Vegetales/farmacología , Animales , Recuento de Células Sanguíneas , Peso Corporal/efectos de los fármacos , Anticonceptivos Masculinos/toxicidad , Fertilidad/efectos de los fármacos , Masculino , Extractos Vegetales/toxicidad , Conejos , Semillas/química , Semen/efectos de los fármacos
10.
Asian J Androl ; 2(2): 103-9, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11232785

RESUMEN

AIM: To examine if the seed extracts of Carica papaya, which showed antispermatogenic/sperm immobilization properties in animal models, could cause human sperm immobilization in vitro. METHODS: Chloroform extract, benzene chromatographic fraction of the chloroform extract, its methanol and ethyl acetate sub-fractions and the isolated compounds from the sub-fractions i.e., ECP 1 & 2 and MCP 1 &2, of the seeds of Carica papaya were used at concentrations of 0.1%, 0.5%, 1% and 2%. Sperm motility was assessed immediately after addition of extracts and every 5 minutes thereafter for 30 minutes. RESULTS: There were dose-dependent spermicidal effects showing an instant fall in the sperm motility to less than 20% at 2% concentration. Isolated compounds ECP 1 & 2 were more effective inducing a motility of less than 10%. Many of the spermatozoa became vibratory on the spot. Total inhibition of motility was observed within 20-25 min at all concentrations of all products. Scanning and transmission electron microscopy revealed deleterious changes in the plasma membrane of the head and mid-piece of spermatozoa. Sperm viability test and the number of abnormal spermatozoa after completion of incubation suggested that the spermatozoa were infertile. The effects were spermicidal but not spermiostatic as revealed by the sperm revival test. CONCLUSION: The results reveal spermicidal activity in vitro of the seed extracts of Carica papaya.


Asunto(s)
Frutas , Inmovilizantes de los Espermatozoides/farmacología , Motilidad Espermática/efectos de los fármacos , Humanos , Masculino , Microscopía Electrónica , Extractos Vegetales/farmacología , Semillas
11.
Reprod Toxicol ; 13(1): 59-66, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10080301

RESUMEN

The contraceptive efficacy and reversibility of the chloroform extract of the seeds of Carica papaya in adult male rabbits were investigated. Eighteen adult male rabbits were divided into three groups of six animals each; Group I--control, Group II--administered chloroform extract of the seeds of Carica papaya at 20 mg/animal/d for 150 d by gavage, and Group III--administered the seed extract at 50 mg/animal/d for 150 d. Body weight and organ weight, semen analysis, sperm morphology by scanning electron microscopy, semen biochemistry, histology of the testis, haematology, serum clinical biochemistry, and the fertility status of the control and the treated animals were evaluated. Body weight and the weight of the testis, epididymis, seminal vesicles, and prostate did not show appreciable changes. Sperm concentration showed a gradual decline, reached severe oligospermia (fewer than 20 million/mL) after 75 d treatment, and attained uniform azoospermia after 120 d treatment. Sperm motility and viability were severely affected after 45 d treatment and reached less than 1% after 75 d treatment. The morphology of the spermatozoa by scanning electron microscopy revealed membrane damage in the acrosome, bent midpiece, coiled tail, and detached head and tail. The levels of fructose, glycerylphosphorylcholine, acid phosphatase, and lactate dehydrogenase in the seminal plasma were unaltered. Histology of the testis revealed arrest of spermatogenesis beyond the level of spermatocytes. No toxicity was evident from the haematology and serum biochemistry parameters. The libido of the treated animals was unaffected and the fertility rate was zero. The effects were comparable in both the dose regimens (Groups II and III) and were restored to normal 45 d after withdrawal of the treatment.


Asunto(s)
Anticonceptivos Masculinos/farmacología , Frutas/química , Extractos Vegetales/farmacología , Animales , Recuento de Células Sanguíneas/efectos de los fármacos , Análisis Químico de la Sangre , Peso Corporal/efectos de los fármacos , Cloroformo/química , Anticonceptivos Masculinos/toxicidad , Fertilidad/efectos de los fármacos , Libido/efectos de los fármacos , Masculino , Tamaño de los Órganos/efectos de los fármacos , Extractos Vegetales/toxicidad , Conejos , Semillas/química , Semen/efectos de los fármacos , Testículo/anatomía & histología , Testículo/citología , Testículo/efectos de los fármacos
12.
Adv Contracept ; 15(2): 141-61, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10997896

RESUMEN

Contraceptive efficacy, reversibility and toxicity, if any, of the benzene, chloroform and ethyl acetate chromatographic fractions of the chloroform extract of the seeds of Carica papaya have been investigated in adult male rabbits at a dose regimen of 50 mg/animal/day for 150 days of treatment. Body weight, semen analysis, hematology, serum clinical biochemistry and the fertility status of control and treated animals were evaluated. Chloroform and ethyl acetate chromatographic fractions did not produce appreciable changes in these parameters. However, the benzene chromatographic fraction resulted in uniform azoospermia after 15 days of treatment, which was maintained for the remainder of the 150-day observation period. The levels of fructose, glycerophosphocholine, acid phosphatase and lactate dehydrogenase in the seminal plasma were within the control range. Hematology and the serum clinical parameters showed no appreciable changes, indicating lack of toxicity. The libido of the treated animals was normal and the fertility rate was zero. Complete normalcy of altered parameters was observed 60 days following withdrawal of treatment. It is concluded that the benzene chromatographic fraction of the chloroform extract of the seeds of Carica papaya possesses reversible male contraceptive potential and the effects appear to be mediated through the testis.


Asunto(s)
Cromatografía , Anticonceptivos Masculinos , Oligospermia/inducido químicamente , Extractos Vegetales/administración & dosificación , Plantas Medicinales , Semillas/química , Acetatos , Animales , Benceno , Cloroformo , Fertilidad , Masculino , Conejos , Conducta Sexual Animal/efectos de los fármacos , Factores de Tiempo
13.
Chem Res Toxicol ; 11(3): 234-40, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9544622

RESUMEN

On-line HPLC/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) in conjunction with NMR has been successfully employed to identify and structurally characterize seven contaminants found in three different commercial preparations of melatonin. Six of these contaminants were identified as analogues of impurities found in contaminated L-tryptophan (an over-the-counter dietary supplement) associated with the eosinophilia-myalgia syndrome (EMS) epidemic that occurred in the United States during 1989. In particular, our studies identified two compounds with MH+ = 249 to be hydroxymelatonin isomers. Four other compounds with MH+ = 477 were identified as melatonin-formaldehyde condensation products. These compounds are structural analogues of L-tryptophan contaminants, namely, 'peak C' and 'peak E' that were previously implicated as etiological agents causing EMS. It has been reported that melatonin consumption has resulted in eosinophilia in some humans taking high doses of this supplement. Although there has not been a major outbreak of EMS-like symptoms from consumption of melatonin, this study clearly suggests that tighter control and regulation of nutritional supplements sold and used as drugs is necessary.


Asunto(s)
Contaminación de Medicamentos , Melatonina/química , Triptófano/química , Cromatografía Líquida de Alta Presión , Brotes de Enfermedades , Síndrome de Eosinofilia-Mialgia/inducido químicamente , Síndrome de Eosinofilia-Mialgia/epidemiología , Formaldehído/química , Humanos , Espectrometría de Masas , Estructura Molecular , Triptófano/efectos adversos , Estados Unidos/epidemiología
14.
Epilepsia ; 37(2): 188-97, 1996 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8635430

RESUMEN

Forebrain seizures were kindled in rats by daily electrical stimulation of the amygdala. Genetically epilepsy-prone rats scoring 9 (GEPR-9s) on the seizure severity scale during audiogenic seizure (AGS) screening ("brainstem seizure-experienced") required fewer stimulations to achieve fully kindled seizures (forelimb clonus with rearing and falling) than control rats. AGS-naive GEPR-9s required an intermediate number of stimulations, indicating a role for both genetic predisposition and previous acoustically evoked brainstem seizure experience. Other forebrain kindling indices such as afterdischarge threshold/duration and seizure latency/duration also involved genetic as well as phenotypic (previous seizure experience) factors. In most GEPR-9s in both groups, severe brainstem seizures occurred after forebrain stimulation. The occurrence of brainstem seizures had a random nature and was not related to the sequence of kindling-dependent forebrain seizure progression. The lack of a difference in the occurrence of brainstem seizures between seizure-experienced and AGS-naive GEPR-9s suggest that genetic predisposition is the major factor in forebrain seizure-induced activation of brainstem seizure circuitry. This brainstem seizure activity appears to model pertinent aspects of secondary generalization observed in human partial seizures.


Asunto(s)
Amígdala del Cerebelo/fisiología , Tronco Encefálico/fisiología , Epilepsia/genética , Excitación Neurológica/fisiología , Prosencéfalo/fisiología , Estimulación Acústica , Animales , Estimulación Eléctrica , Electroencefalografía , Epilepsia/etiología , Humanos , Ratas , Ratas Sprague-Dawley , Convulsiones/genética
15.
Ital J Neurol Sci ; 16(1-2): 91-9, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7642359

RESUMEN

Two independently inbred strains of genetically epilepsy-prone rats (GEPRs) have been developed. GEPR-3s and GEPR-9s have moderate and severe degrees of seizure predisposition as well as expression, respectively. Seizure predisposition is a fundamental distinction between the normal and epileptic brain. Seizure predisposition in GEPRs and in humans with epilepsy includes spontaneous seizures and exaggerated seizure responsiveness and/or abnormally low thresholds to stimuli which also cause seizures in non-epileptic subjects. Activation of brainstem seizure circuitry by auditory input via the inferior colliculus causes electrographic and behavioral responses in GEPR-9s which replicates human generalized tonic/clonic seizures. Activation of brainstem seizure circuitry by input from forebrain seizure circuitry in GEPRs provides a newly discovered model of complex partial seizures with secondary generalization to tonic/clonic seizures. Thus, seizure predisposition in GEPRs offers a unique opportunity to study the human epilepsies that is not offered in studies of normal brain exposed to convulsant stimuli.


Asunto(s)
Epilepsia/genética , Animales , Anticonvulsivantes/uso terapéutico , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Evaluación Preclínica de Medicamentos , Electroencefalografía , Humanos , Ratas , Ratas Sprague-Dawley
16.
Synapse ; 12(2): 87-98, 1992 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-1362291

RESUMEN

This study was designed to determine the effects of N-methyl-D-aspartate (NMDA) receptor stimulation on the electrical activity of neocortex in freely behaving rats. Electroencephalogram (EEG) recording and intracerebral microdialysis were conducted simultaneously in the same site of the sensorimotor cortex, where the basal extracellular concentrations of aspartate and glutamate were 2.1 +/- 0.7 microM and 11.5 +/- 2.4 microM, respectively. Microdialysis with NMDA solutions (ranging from 10.0 microM to 10.0 mM) reduced the amplitude of the EEG activity and decreased the power of all frequency bands, with a virtual elimination of the high frequency waves, in a dose-dependent manner. These EEG changes were reversed after washing out the drug from the microdialysis fluid, and could be effectively antagonized with the competitive NMDA receptor antagonist DL-2-amino-5-phosphonovalerate. Remarkably, the NMDA actions were not associated with epileptiform behavioral or electrographic events. Control studies demonstrated that in the same experimental conditions, cholinergic receptor agonist carbachol caused seizures, and microdialysis with NMDA in the hippocampus readily induced epileptiform spikes. Our study shows that NMDA receptor stimulation in the rat sensorimotor cortex, although excitatory at synaptic level, can depress the local EEG activity. This may indicate that the NMDA receptor-mediated signals are processed by the neocortical network in a different way than by many other brain circuitries including hippocampus.


Asunto(s)
Corteza Motora/fisiología , Receptores de N-Metil-D-Aspartato/fisiología , Corteza Somatosensorial/fisiología , 2-Amino-5-fosfonovalerato/farmacología , Animales , Conducta Animal/efectos de los fármacos , Carbacol/farmacología , Líquido Cefalorraquídeo , Diálisis/métodos , Electroencefalografía , Electrofisiología , Hipocampo/efectos de los fármacos , Hipocampo/fisiología , Masculino , Corteza Motora/efectos de los fármacos , Corteza Motora/metabolismo , N-Metilaspartato/farmacología , Perfusión , Ratas , Ratas Sprague-Dawley , Corteza Somatosensorial/efectos de los fármacos , Corteza Somatosensorial/metabolismo
17.
J Pharmacol Exp Ther ; 260(2): 533-40, 1992 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1738103

RESUMEN

Fluoxetine, an antidepressant and inhibitor of serotonin reuptake, was evaluated as an anticonvulsant in genetically epilepsy-prone rats (GEPRs) because seizure predisposition in GEPRs is partially dependent on deficits in brain serotonin. Fluoxetine produced dose-dependent reductions in sound-induced convulsion intensity in both moderate seizure GEPRs and severe seizure GEPRs with the peak anticonvulsant effect occurring 4 hr after i.p. administration. A subchronic study in severe seizure GEPRs demonstrated that the ED50 after 28 days of dosing (8.2 mg/kg) was lower than the acute ED50 (15.9 mg/kg) so that there was no apparent development of tolerance. The lower ED50 after subchronic administration apparently resulted from accumulation of fluoxetine and its metabolite norfluoxetine in brain. Brain microdialysis studies showed that acute fluoxetine administration resulted in a significant increase in extracellular serotonin concentration in the thalamus. The increase in serotonin concentration in the dialysate corresponded temporally with the anticonvulsant effect produced by fluoxetine. Intrathalamic administration of fluoxetine via the dialysis probe caused an increase in serotonin concentration in the dialysate, suggesting that the effect of fluoxetine was on nerve terminals. Fluoxetine could be dialyzed from thalamus after its i.p. administration. Fluoxetine concentration in the thalamic dialysate was similar to the concentration found in plasma. We conclude that fluoxetine is an effective anticonvulsant in GEPRs and that the microdialysis results strongly suggest a relationship between the effects of fluoxetine on serotonergic neurons and the anticonvulsant effect produced by this drug.


Asunto(s)
Encéfalo/efectos de los fármacos , Epilepsia/genética , Fluoxetina/uso terapéutico , Convulsiones/tratamiento farmacológico , Serotonina/metabolismo , Animales , Diálisis , Femenino , Fluoxetina/análogos & derivados , Fluoxetina/sangre , Fluoxetina/farmacología , Masculino , Ratas , Tálamo/efectos de los fármacos
18.
Epilepsy Res ; 3(1): 3-17, 1989.
Artículo en Inglés | MEDLINE | ID: mdl-2563686

RESUMEN

Seizure predisposition in the genetically epilepsy-prone rat (GEPR) is innately determined and these animals exhibit consistent and reproducible convulsive patterns. This epilepsy model is made up of 2 independently derived colonies of animals with each exhibiting a characteristic convulsive pattern. In response to a standardized acoustic stimulus, GEPR-3s exhibit moderate or clonic convulsions and GEPR-9s exhibit more severe tonic extensor convulsions. Besides exhibiting convulsions in response to sound stimulation, some GEPRs experience spontaneous and hyperthermic seizures. They are also abnormally sensitive to a number of seizure provoking stimuli that produce seizures in normal animals. The neurochemical basis for the seizure predisposition in GEPRs is increasingly well understood. Abnormalities in central nervous system norepinephrine and serotonin are widespread and may play a prominent role in regulation of seizures in the GEPR. Amino acid neurotransmitter systems are less well defined in the GEPR but abnormalities exist and may be, along with other documented deficiencies, responsible in part for the seizure predisposition that is characteristic of GEPRs.


Asunto(s)
Vías Auditivas/fisiopatología , Modelos Animales de Enfermedad , Ratas Mutantes/fisiología , Convulsiones/genética , Estimulación Acústica , Animales , Anticonvulsivantes/uso terapéutico , Neurotransmisores/metabolismo , Ratas , Convulsiones/metabolismo , Convulsiones/fisiopatología
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