Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Diabet Med ; 37(12): 2109-2115, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32353892

RESUMEN

AIMS: To compare diagnosis characteristics, diabetes management and comorbidities in a population diagnosed with type 1 diabetes in childhood with those in a similar population diagnosed in adulthood to identify disease differences related to the age of diabetes onset. METHODS: This analysis was performed using the T1D Exchange Clinic Registry, a cross-sectional survivor cohort. Retrospectively collected characteristics were compared across the following age-at-diagnosis groups: <10, 10-17, 18-24, 25-39 and ≥40 years. RESULTS: The entire cohort included 20 660 participants [51% female, median (interquartile range) age 18 (14-36) years, 82% non-Hispanic white]. Diabetic ketoacidosis at diagnosis was more common among those with onset in childhood. Participants diagnosed as adults were more likely to be overweight/obese at diagnosis and to have used oral agents preceding type 1 diabetes diagnosis (57%). Current insulin pump use was less frequent in participants diagnosed at older ages. Current glycaemic control, measured by HbA1c , insulin requirements and use of a continuous glucose monitor were not different by age at diagnosis. Coeliac disease was the only comorbidity that was observed to have a different frequency by age at diagnosis, being more common in the participants diagnosed at a younger age. CONCLUSIONS: These results show differences and similarities between type 1 diabetes diagnosed in childhood vs adulthood; notably, there was a tendency for there was a higher frequency of diabetic ketoacidosis at onset in children and a higher frequency of use of oral antidiabetes agents in adults. The data indicate that there is little distinction between the clinical characteristics and outcomes of type 1 diabetes diagnosed in childhood vs adulthood. Optimizing glycaemic control remains a challenge in all age groups, with lower use of insulin pumps impacting those diagnosed as adults.


Asunto(s)
Diabetes Mellitus Tipo 1/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Adolescente , Adulto , Edad de Inicio , Automonitorización de la Glucosa Sanguínea , Niño , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Femenino , Hemoglobina Glucada/metabolismo , Humanos , Bombas de Infusión Implantables , Insulina/uso terapéutico , Sistemas de Infusión de Insulina , Masculino , Triglicéridos/sangre , Adulto Joven
2.
Transplant Proc ; 47(9): 2727-31, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26680082

RESUMEN

PURPOSE: Hyperglycemia increases risks of kidney and liver transplant rejection. To determine whether perioperative and subsequent glycemic control was associated with increased risk of heart transplant rejection over the year after transplantation, we performed a retrospective analysis of glycemic control and rejection rates in heart transplantation patients. METHODS: Perioperative glucose levels were analyzed in 157 patients undergoing transplantation at Northwestern Memorial Hospital from June 2005 to December 2012 and compared in patients with and without rejection found on routine follow-up biopsy specimens. RESULTS: Grade ≤1R rejection on biopsy was observed in 116 patients and grade ≥2R rejection (grade requiring increased anti-rejection treatment) in 41 patients. Although no significant differences in the preoperative fasting or inpatient mean glucose levels were found, the mean glucose levels from discharge to 1 year trended higher in those with grade ≥2R compared to grade ≤1R (128.8 ± 40.9 versus 142.2 ± 46.6 mg/dL, P = .084). In a multivariable logistic regression model, neither the lowest nor highest quartile of glucose levels had significantly different odds ratios (ORs) for the development of ≥2R compared to the middle 50% glucose levels. Older age (OR 0.96, P = .020) and higher body mass index levels (OR 0.86, P = .004) were significantly associated with lower odds of developing grade ≥2R. CONCLUSIONS: Although the glucose trend regarding rejection was not statistically significant, we cannot exclude the possibility that much higher glucose levels would influence rejection rates.


Asunto(s)
Rechazo de Injerto/etiología , Trasplante de Corazón/efectos adversos , Hiperglucemia/complicaciones , Complicaciones Posoperatorias/etiología , Adulto , Anciano , Biopsia , Glucemia/análisis , Femenino , Estudios de Seguimiento , Rechazo de Injerto/sangre , Rechazo de Injerto/patología , Humanos , Hiperglucemia/sangre , Modelos Logísticos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/sangre , Complicaciones Posoperatorias/patología , Estudios Retrospectivos
3.
Endocrinology ; 138(3): 1058-65, 1997 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9048609

RESUMEN

Repeated stimulation of pituitary cell cultures with GH-releasing hormone (GHRH) results in diminished responsiveness, a phenomenon referred to as homologous desensitization. One component of GHRH-induced desensitization is a reduction in GHRH-binding sites, which is reflected by the decreased ability of GHRH to stimulate a rise in intracellular cAMP. In the present study, we sought to determine if homologous down-regulation of GHRH receptor number is due to a decrease in GHRH receptor synthesis. To this end, we developed and validated a quantitative RT-PCR assay system that was capable of assessing differences in GHRH-R messenger RNA (mRNA) levels in total RNA samples obtained from rat pituitary cell cultures. Treatment of pituitary cells with GHRH, for as little as 4 h, resulted in a dose-dependent decrease in GHRH-R mRNA levels. The maximum effect was observed with 0.1 and 1 nM GHRH, which reduced GHRH-R mRNA levels to 49 +/- 4% (mean +/- SEM) and 54 +/- 11% of control values, respectively (n = three separate experiments; P < 0.05). Accompanying the decline in GHRH-R mRNA levels was a rise in GH release; reaching 320 +/- 31% of control values (P < 0.01). Because of the possibility that the rise in medium GH level is the primary regulator of GHRH-R mRNA, we pretreated pituitary cultures for 4 h with GH to achieve a concentration comparable with that induced by a maximal stimulation with GHRH (8 micrograms GH/ml medium). Following pretreatment, cultures were stimulated for 15 min with GHRH and intracellular cAMP accumulation was measured by RIA. GH pretreatment did not impair the ability of GHRH to induce a rise in cAMP concentrations. However, as anticipated, GHRH pretreatment (10 nM) significantly reduced subsequent GHRH-stimulated cAMP to 46% of untreated controls. These data suggest that GHRH, but not GH, directly reduces GHRH-R mRNA levels. To determine whether this effect was mediated through cAMP, cultures were treated with forskolin, a direct stimulator of adenylate cyclase. Forskolin (10 microM) significantly reduced GHRH-R mRNA concentrations (37 +/- 6% of control values) indicating that GHRH acts through the cAMP-second messenger system cascade to regulate GHRH-R mRNA. The somatostatin analogue, octreotide (10 nM), which has been previously reported to decrease adenylate cyclase activity, did not affect GHRH-R mRNA levels. Taken together, these results indicate that GHRH inhibits the production of its own receptor by a receptor-mediated, cAMP-dependent reduction of GHRH-R mRNA accumulation.


Asunto(s)
Regulación hacia Abajo , ARN Mensajero/metabolismo , Receptores de Neuropéptido/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Animales , Células Cultivadas , Colforsina/farmacología , Medio de Cultivo Libre de Suero , Dexametasona/farmacología , Femenino , Hormona Liberadora de Hormona del Crecimiento/farmacología , Octreótido/farmacología , Adenohipófisis/citología , Adenohipófisis/metabolismo , Reacción en Cadena de la Polimerasa , Ratas , Ratas Sprague-Dawley , Transcripción Genética
4.
Endocrinology ; 137(11): 4630-6, 1996 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8895326

RESUMEN

Dwarf tyrosine hydroxylase-human GH (TH-hGH) transgenic mice carrying the hGH reporter gene targeted by the TH promoter express hGH in those regions of the hypothalamus responsible for regulation of pituitary GH secretion. Central expression of the hGH gene decreases GH-releasing hormone (GHRH) and increases somatostatin, which ultimately impacts on pituitary function by reducing the overall amount of GH produced. In the present study, we sought to determine if the reduction of pituitary GH in TH-hGH mice could be attributed to a decrease in somatotrope cell numbers and/or an impairment of somatotrope function. Pituitaries from TH-hGH or wild-type (WT) male and female mice were enzymatically dispersed, counted, and immunostained for GH, PRL, TSH, and ACTH. The total number of pituitary cells recovered from TH-hGH pituitaries was approximately one-half of that from WT controls. However, the proportion of cells that stained for GH and PRL were virtually identical (males, GH-TH-hGH, 58.1 +/- 1.0% [mean +/- SEM] vs. WT, 60.7 +/- 1.0%; PRL-TH-hGH, 43.4 +/- 2.2% vs. WT, 43.1 +/- 0.7%; females, GH-TH-hGH, 47.9 +/- 2.3% vs. WT, 41.5 +/- 3.5%; PRL-TH-hGH, 43.3 +/- 3.2% vs. WT, 47.1 +/- 3.3%). In contrast, percentages of both TSH- and ACTH-containing cells were increased in TH-hGH pituitaries relative to controls (males, TSH-TH-hGH, 15.1 +/- 2.3% vs. WT, 9.6 +/- 1.5%; ACTH-TH-hGH, 24.5 +/- 2.5% vs. WT, 10.9 +/- 0.9%; females: TSH-TH-hGH, 11.3 +/- 0.7% vs. WT, 7.5 +/- 0.6%; ACTH-TH-hGH, 19.8 +/- 1.6% vs. WT, 9.3 +/- 0.8%; P < 0.05). Calculation of the absolute number of each cell type per pituitary demonstrated TH-hGH mice to have about one-half the number of GH and PRL cells, whereas TSH and ACTH cell populations were comparable with that of their WT counterparts. Immunocytochemical localization of GH cells within pituitary sections from TH-hGH mice revealed that somatotropes were confined primarily to the lateral wings of the adenohypophysis, in contrast to the heterogeneous distribution of GH-immunostained cells in WT pituitaries. To assess the functional capacity of the somatotrope populations, pituitary cells from TH-hGH and WT mice were challenged with mouse GHRH (0.01-10 nM). The quantity of GH released (as assessed by both RIA and reverse hemolytic plaque assay) under basal and stimulated conditions did not differ among TH-hGH and WT pituitary cell cultures. Similarly, GHRH induced intracellular cAMP levels were comparable. These results indicate that proliferation of pituitary somatotropes and lactotropes is much more sensitive to changes in GHRH input than is the capability of developing regulated GH secretory function.


Asunto(s)
Hormona del Crecimiento/deficiencia , Hormona de Crecimiento Humana/genética , Hipotálamo/fisiología , Adenohipófisis/metabolismo , Regiones Promotoras Genéticas , Tirosina 3-Monooxigenasa/genética , Hormona Adrenocorticotrópica/biosíntesis , Animales , Peso Corporal , Células Cultivadas , Femenino , Hormona de Crecimiento Humana/biosíntesis , Humanos , Hipotálamo/fisiopatología , Masculino , Ratones , Ratones Transgénicos , Adenohipófisis/citología , Prolactina/biosíntesis , Caracteres Sexuales , Tirotropina/biosíntesis , Tirosina 3-Monooxigenasa/biosíntesis
5.
Eur J Neurosci ; 8(11): 2407-15, 1996 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8950104

RESUMEN

We have characterized the expression pattern and pharmacological profile of activation of metabotropic glutamate receptors (mGluRs) in immortalized, gonadotropin releasing hormone (GnRH)-secreting GT1-7 cells, which represent a homogeneous cellular population of hypothalamic origin. These cells are known to respond to the mGluR agonist (1S,3R)-cyclopentanedicarboxylic acid (1S,3R-ACPD) with increased GnRH release. To establish which specific mGluR subtypes are expressed by GT1-7 cells, we used polyclonal antibodies raised against non-conserved regions of the carboxy-terminal domains of individual subtypes. The selectivity of these antibodies was tested in HEK 293 cells transiently transfected with each mGluR subtype. GT1-7 cells stained positively for the subtypes mGluR1a, -1b and -5 (belonging to group I mGluR2/3 (group II) and mGluR7 (group III). Agonists of group I mGluRs, including 1S,3R-ACPD, activated phosphoinositide hydrolysis in GT1-7 cells. This effect, however, was manifested only when cell density was low, and it disappeared when cells reached confluence. Stimulation of phosphoinositide hydrolysis could not therefore have been related to hormone secretion because 1S,3R-ACPD effectively released GnRH in confluent cultures. We then focused on group II and III mGluRs, which in transfected cells are negatively linked to adenylate cyclase activity. Unexpectedly, however, agonist which preferentially activate group II and III mGluRs increased both basal and forskolin-stimulated cAMP accumulation in GT1-7 cells. Stimulation of cAMP accumulation by mGluR agonists was not prevented by enzymatic depletion of endogenous adenosine, but was obliterated when cells were incubated with agonists of receptors positively coupled to adenylate cyclase, such as beta-adrenergic and prostaglandin E2 receptors. These results suggest that GT1-7 cells express a novel mGluR subtype positively coupled to adenylate cyclase, which shares the same transduction pathway of other classical receptors coupled with a Gs-type of GTP-binding protein.


Asunto(s)
AMP Cíclico/metabolismo , Cicloleucina/análogos & derivados , Hormona Liberadora de Gonadotropina/biosíntesis , Hipotálamo/metabolismo , Neuronas/metabolismo , Receptores de Glutamato Metabotrópico/biosíntesis , Animales , División Celular , Línea Celular Transformada , Colforsina/farmacología , Cicloleucina/farmacología , Dinoprostona/farmacología , Agonistas de Aminoácidos Excitadores/farmacología , Hormona Liberadora de Gonadotropina/metabolismo , Ratones , Neuronas/citología , Neuronas/efectos de los fármacos , Norepinefrina/farmacología , Fosfatidilinositoles/metabolismo , Ácido Quiscuálico/farmacología , Receptores de Glutamato Metabotrópico/agonistas
6.
Brain Res Bull ; 41(6): 359-62, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8973840

RESUMEN

GnRH release from hypothalamic explants from young and aged male Wistar-Kyoto rats was evaluated following stimulation with glutamate receptor agonists. Glutamate stimulated GnRH release to a similar extent in hypothalami from young and old animals, whereas N-methyl-D-Aspartate (NMDA) and kainate appeared more efficacious in young and old rats, respectively. Old rats were unable to respond to a maximal stimulating concentration of glutamate when they had been previously exposed to a challenge with the same agent. These results demonstrate that responsiveness to glutamate receptor agonists changes during aging, suggesting the involvement of distinct glutamate receptors in the control of GnRH release during different phases of lifespan.


Asunto(s)
Envejecimiento/metabolismo , Hormona Liberadora de Gonadotropina/metabolismo , N-Metilaspartato/farmacología , Receptores de Glutamato/efectos de los fármacos , Factores de Edad , Envejecimiento/efectos de los fármacos , Animales , Masculino , Ratas , Ratas Endogámicas WKY
7.
J Neural Transm Suppl ; 45: 297-305, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-8748638

RESUMEN

Dihydroergocryptine is an ergot alkaloid endowed with pharmacological actions mainly related to its dopaminomimetic activity. Free radical formation and subsequent lipid peroxidation had been postulated to participate broadly to the pathogenesis of tissue injury, including the brain injury induced by hypoxia, ischemia or trauma, as well as in the physiopathology of chronic neurodegenerative diseases, such as Parkinson's disease. Here we report that dihydroergocryptine protects cultured rat cerebellar granule cells against age-dependent and glutamate-induced neurotoxicity. Dihydroergocryptine antagonizes in fact both the neuronal death produced by acute exposure to a toxic glutamate concentration as well as the normal age-dependent degeneration in culture, presumably by exerting a scavenger action. This effect does not seem mediated entirely by interactions with the dopamine D2 receptors. The neuroprotective action of dihydroergocryptine suggests a potential usefulness in halting the acute and chronic neurodegenerative diseases related to excitotoxic damage and free radical formation, including Parkinson's disease.


Asunto(s)
Dihidroergotoxina/farmacología , Agonistas de Dopamina/farmacología , Peroxidación de Lípido/efectos de los fármacos , Degeneración Nerviosa/efectos de los fármacos , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Animales , Células Cultivadas , Radicales Libres , Humanos
8.
Endocrinology ; 134(4): 1782-7, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7511093

RESUMEN

A role for nitric oxide (NO) in the regulation of hypothalamic neurohormone secretion has been suggested. The aim of the present study was to establish a direct involvement of this novel intracellular regulatory molecule in the control of GnRH release. For this purpose, the GT1-1 GnRH-secreting continuous cell line was treated with various agents that can modify the endogenous NO synthase activity or, alternatively, with substances that can liberate NO, mimicking an increased concentration of this molecule in the cell. Treatment of GT1-1 cells with increasing concentrations of L-arginine, the direct precursor of NO, produced a marked reduction of norepinephrine-stimulated GnRH release despite a lack of effect on basal secretion. Similarly, the NO donors SIN-1 and acidified NaNO2 potently reduced basal as well as KCl-stimulated GnRH secretion. Conversely, sodium nitroprusside caused a significant inhibition of KCl-stimulated, but not basal, GnRH secretion. Addition of these agents to GT1-1 cells resulted in a marked increase in intracellular cGMP accumulation. Addition of the NO synthase inhibitors N-nitro-L-arginine and N-nitro-L-arginine methyl ester stimulated basal GnRH secretion without modifying norepinephrine- or KCl-stimulated release. In addition, treatment of GT1-1 cells with both L-arginine analogs produced a significant inhibition of the basal cGMP concentration. Together, these data suggest an inhibitory role for NO in the control of GnRH secretion from GT1-1 cells.


Asunto(s)
Hormona Liberadora de Gonadotropina/metabolismo , Neuronas/metabolismo , Óxido Nítrico/fisiología , Aminoácido Oxidorreductasas/antagonistas & inhibidores , Animales , Arginina/análogos & derivados , Arginina/farmacología , Línea Celular , GMP Cíclico/metabolismo , Hormona Liberadora de Gonadotropina/antagonistas & inhibidores , Ratones , Ratones Transgénicos , Molsidomina/análogos & derivados , Molsidomina/farmacología , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa , Nitroprusiato/farmacología , Norepinefrina/farmacología , Nitrito de Sodio/farmacología
9.
Endocrinology ; 134(3): 1219-24, 1994 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8119162

RESUMEN

Expression of the mouse GH-releasing hormone (GRH) gene is restricted to neurons within the hypothalamus and to placenta. In an attempt to generate immortalized mouse hypothalamic neurons expressing GRH, the proximal 872-nucleotide segment of the 5'-flanking region of the hypothalamic mouse GRH gene was cloned by polymerase chain reaction and ligated to a 2.7-kilobase DNA sequence encoding the simian virus-40 (SV40) T-antigen, so that regulation of SV40 T-antigen expression was dependent on sequences within the mGRH 5'-flanking region. This region contains both TATA and CAAT boxes. The mouse GRH/SV40 T-antigen fusion gene was injected into 1-cell mouse embryos, and SV40 T-antigen incorporation in the mouse genome was found in 11 of 77 live births (3 males and 8 females). Although no evidence of hypothalamic tumors was found, all mice that expressed the transgene also developed tumors originating in the adrenal medulla. Gene copy number varied from 1-20 and was inversely proportional to survival, which ranged from 7-16 weeks. Corticosterone levels were normal. The male transgenic mice were fertile, and their progeny expressed the transgene and developed similar tumors. Microscopic examination of the tumors revealed a primitive neuroectodermal neoplasm that exhibited hematogenous and lymph node metastases and contained 100 ng norepinephrine, 2.85 ng epinephrine, and 1.1 ng dopamine/mg tumor tissue. Primary culture of dispersed tumor cells released norepinephrine into the medium (180 pg/ml.24 h). Cell lines from 2 tumors were established and exhibited characteristics similar to those of mixed neuroblastoma or primitive neuroectodermal tumors. In conclusion, the proximal 872 nucleotides of the hypothalamic mouse GRH promoter contain elements directing tissue-specific expression limited to early adrenal neuroectodermal cells. Other GRH DNA sequences appear to be required for restricted expression of mouse GRH within the hypothalamus.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales/etiología , Médula Suprarrenal , Antígenos Transformadores de Poliomavirus/genética , Hormona Liberadora de Hormona del Crecimiento/genética , Neoplasias Neuroepiteliales/etiología , Virus 40 de los Simios/inmunología , Animales , Secuencia de Bases , Clonación Molecular , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Datos de Secuencia Molecular , Células Tumorales Cultivadas
10.
Pharmacol Toxicol ; 74(2): 95-100, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8190709

RESUMEN

Repeated, but not single injections of L-alpha-glyceryl-phosphorylcholine (alpha GPC) significantly increased basal [3H]inositol monophosphate (InsP) formation in hippocampal, cortical, and striatal slices of male rats. The effect was dose-dependent and was accompanied by an increased incorporation of [3H]inositol into the phospholipid fraction. Incubation of brain slices with different neurotransmitter antagonists, such as atropine, prazosin, or L-2-amino-4-phosphonobutanoate (L-AP4) did not modify the increase in [3H]InsP formation produced by alpha GPC, suggesting that the effect is not mediated by an increased availability of a specific neurotransmitter. Similar results were obtained in cerebellar and cortico-striatal neurones in primary culture exposed to daily addition of alpha GPC since the second day of maturation in vitro. We suggest that alpha GPC treatment may result in an increased rate of phospholipid synthesis, including the phosphoinositides available for signal transduction at central nervous system level.


Asunto(s)
Encéfalo/efectos de los fármacos , Glicerilfosforilcolina/farmacología , Fosfatos de Inositol/biosíntesis , Neuronas/efectos de los fármacos , Animales , Encéfalo/metabolismo , Células Cultivadas , Hidrólisis , Inositol/metabolismo , Masculino , Neuronas/metabolismo , Técnicas de Cultivo de Órganos , Ratas , Ratas Sprague-Dawley
11.
Pharmacol Toxicol ; 73(4): 224-8, 1993 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7905201

RESUMEN

Dihydroergocryptine is a hydrogenated ergot derivative with pharmacological actions mainly related to its dopaminomimetic activity. Here we report that dihydroergocryptine can protect cultured rat cerebellar granule cells against glutamate-induced neurotoxicity, assessing cell viability with the fluorescein diacetate-propidium iodide technique. Dihydroergocryptine antagonized both the neuronal death produced by acute exposure to a toxic glutamate concentration as well as the normal age-dependent degeneration in culture. The effect of dihydroergocryptine might be mediated by a scavenger action as suggested by the fact that the compound in a concentration-dependent manner reduced the formation of intracellular peroxides produced in cerebellar granule cells by exposure to 100 microM glutamate. This action is apparently not mediated entirely by interactions with the dopamine D2 receptors. The neuroprotective action suggests that dihydroergocryptine might be a potential useful drug in the therapy and/or prophylaxis of acute and chronic neurodegenerative diseases related to excitotoxic damage.


Asunto(s)
Corteza Cerebelosa/efectos de los fármacos , Dihidroergotoxina/farmacología , Antagonistas de Aminoácidos Excitadores , Envejecimiento , Animales , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Corteza Cerebelosa/citología , Relación Dosis-Respuesta a Droga , Fluoresceínas/metabolismo , Glutamatos/toxicidad , Ácido Glutámico , Degeneración Nerviosa/efectos de los fármacos , Neuronas/efectos de los fármacos , Peróxidos/metabolismo , Propidio , Ratas
12.
Gynecol Endocrinol ; 7(2): 89-96, 1993 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8213232

RESUMEN

Three different calcitonins: salmon calcitonin, eel calcitonin and the semi-synthetic analog [Asu1,7]eel calcitonin have been evaluated for their ability to affect phosphoinositide hydrolysis in primary cultures of anterior pituitary cells and in the osteoblast-like UMR-106 cells. In both cellular systems a repeated treatment with any form of calcitonin induced an inhibition of inositol phospholipid turnover. Eel calcitonin and its analog were always more potent than salmon calcitonin, but the efficacy of the three polypeptides was comparable. In cultured anterior pituitary cells, the inhibitory effect on phosphoinositide hydrolysis observed after chronic treatment with calcitonin was accompanied by a reduction of prolactin release. In contrast, a single treatment of cultured anterior pituitary cells with eel calcitonin or its analog [Asu1,7]eel calcitonin induced an increase of inositol phosphate accumulation, while salmon calcitonin was inactive. Accordingly, eel and [Asu1,7]eel calcitonin, but not salmon calcitonin, induced a slight but significant stimulation of prolactin secretion. In UMR-106 cells, the three calcitonins exhibited similar potency and efficacy in reducing parathyroid hormone-stimulated 4 beta[3H]-phorbol-12,13-dibutyrate ([3H]PdBu) binding, an indirect index of protein kinase C activation. Taken together, these results suggest that, either at the pituitary or in osteoblast-like cells, some of the effects exerted by calcitonin may be ascribed to an interference with the intracellular events initiated by modulation of phosphoinositide turnover.


Asunto(s)
Calcitonina/farmacología , Osteoblastos/efectos de los fármacos , Adenohipófisis/efectos de los fármacos , Análisis de Varianza , Animales , Calcitonina/análogos & derivados , Células Cultivadas , Células Clonales , Relación Dosis-Respuesta a Droga , Anguilas , Hidrólisis , Fosfatos de Inositol/biosíntesis , Masculino , Osteoblastos/metabolismo , Hormona Paratiroidea/farmacología , Forbol 12,13-Dibutirato/metabolismo , Adenohipófisis/metabolismo , Prolactina/biosíntesis , Ratas , Ratas Sprague-Dawley , Salmón , Hormona Liberadora de Tirotropina/farmacología
13.
Funct Neurol ; 8(3): 183-8, 1993.
Artículo en Inglés | MEDLINE | ID: mdl-8406136

RESUMEN

The effect of dihydroergocryptine, a natural alkaloid derivative which exhibits D2 dopaminomimetic properties, has been studied in Lewis female rats with experimentally induced allergic encephalomyelitis. A chronic treatment with dihydroergocryptine started two days before immunization, induced a dramatic reduction of prolactin levels accompanied by a marked amelioration of neurological signs. In addition, the proliferative activity of splenic lymphocytes induced by the mitogen Concanavalin-A (Con-A) was reduced in dihydroergocryptine-treated animals. It is suggested that this effect is related to the ability of dihydroergocryptine to lower prolactin concentrations or also, partially, to a neuroprotective action of this drug.


Asunto(s)
Dihidroergotoxina/farmacología , Encefalomielitis Autoinmune Experimental/fisiopatología , Animales , Sistema Nervioso Central/efectos de los fármacos , Sistema Nervioso Central/inmunología , Sistema Nervioso Central/fisiopatología , Encefalomielitis Autoinmune Experimental/inmunología , Femenino , Activación de Linfocitos/efectos de los fármacos , Activación de Linfocitos/inmunología , Examen Neurológico/efectos de los fármacos , Prolactina/sangre , Ratas , Ratas Endogámicas Lew
14.
Brain Res ; 600(1): 166-8, 1993 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-7678535

RESUMEN

We have tested the interaction between amyloid beta protein (A beta P) and tachykinin receptors in cultured UC-11MG astrocytoma cells, which express high affinity substance P receptors and respond to substance P with an unusually large stimulation of polyphosphoinositide hydrolysis. Both the full-length A beta P (A beta P1-40) and the fragment 25-35 (A beta P25-35) did not affect the stimulation of [3H]inositolmonophosphate (InsP) formation by substance P. A beta P25-35 was also inactive when applied to the cultures 18 or 72 h prior to the assay. In addition, A beta P25-35 did not displace specifically bound [3H]SarMet substance P from its recognition sites in intact UC-11MG cells. These results suggest that, at least in this specific cell type, amyloid peptides do not interact with substance P receptors.


Asunto(s)
Péptidos beta-Amiloides/farmacología , Astrocitoma/metabolismo , Fosfatos de Inositol/metabolismo , Fosfatidilinositoles/metabolismo , Receptores de Neurotransmisores/metabolismo , Dimetilsulfóxido/farmacología , Humanos , Fragmentos de Péptidos/farmacología , Fosfatos de Fosfatidilinositol , Receptores de Neurotransmisores/efectos de los fármacos , Receptores de Taquicininas , Sustancia P/análogos & derivados , Sustancia P/metabolismo , Sustancia P/farmacología , Células Tumorales Cultivadas
15.
Funct Neurol ; 7(5): 413-22, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1338053

RESUMEN

The nootropic drug, aniracetam, behaves as a positive modulator of AMPA-sensitive glutamate receptors in a variety of systems, including intact brain tissue, amphibian oocytes injected with rat brain mRNA, and cultured neurons. In electrophysiological studies, aniracetam both increases the peak amplitude and reduces the rate of decay of the ion current generated by AMPA or quisqualate. In cultured neurons, aniracetam (as well as oxiracetam and piracetam) enhances the stimulation of 45Ca2+ influx produced by AMPA but not that produced by kainate or NMDA. In addition, aniracetam (as other nootropic drugs) increases the maximal density of low affinity binding sites for [3H]AMPA in crude synaptic membranes. Positive modulation of AMPA receptors by aniracetam provides a novel molecular substrate which explains the clinical efficacy of nootropic drugs as memory and cognition enhancers.


Asunto(s)
Aminoácidos/metabolismo , Encéfalo/efectos de los fármacos , Plasticidad Neuronal/efectos de los fármacos , Pirrolidinonas/farmacología , Receptores de Glutamato/efectos de los fármacos , Animales , Encéfalo/metabolismo , Calcio/metabolismo , Células Cultivadas , Aprendizaje/efectos de los fármacos , Masculino , Memoria/efectos de los fármacos , Ratas , Receptores AMPA , Membranas Sinápticas/efectos de los fármacos , Xenopus
16.
Eur J Pharmacol ; 226(3): 273-7, 1992 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-1330635

RESUMEN

The mechanism of action of ipriflavone, an isoflavone derivative, was studied in the osteoblastic-like UMR-106 cell line. Ipriflavone affected both phosphoinositide hydrolysis and 45Ca2+ uptake. A repeated treatment of UMR-106 cells (once a day, for 3 days) with ipriflavone decreased, in a concentration-dependent manner, [3H]inositol monophosphate accumulation. This effect was also achieved after single addition of high concentrations of ipriflavone or 100 nM [Asu1,7]eel-calcitonin, a semi-synthetic analog of eel calcitonin. When repeatedly added to UMR-106 cells, 17 beta-estradiol produced a marked inhibition of [3H]inositol monophosphate accumulation, an effect which appeared significant only at a concentration of 1 microM and which was accompanied by a reduced incorporation of [3H]inositol into membrane phospholipids. A repeated treatment with ipriflavone reduced 45Ca2+ uptake as well. This effect was observed also after a single addition of [Asu1,7]eel-calcitonin but not following single or repeated treatment with 17 beta-estradiol. The present data indicate the osteoblast as a direct and specific target for ipriflavone and suggest that this compound may share intracellular transducing mechanisms with other antiosteoporotic hormones such as estrogen and calcitonin.


Asunto(s)
Calcio/metabolismo , Isoflavonas/farmacología , Osteoblastos/metabolismo , Fosfatidilinositoles/metabolismo , Calcitonina/farmacología , Radioisótopos de Calcio , Línea Celular , Estradiol/farmacología , Hidrólisis , Osteoblastos/efectos de los fármacos , Transducción de Señal/efectos de los fármacos
17.
Funct Neurol ; 7(4): 275-81, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1330841

RESUMEN

Repeated addition of CDP-choline (100 microM, once a day since the 2nd day of maturation in culture) to corticostriatal neurons led to an increased basal hydrolysis of inositol phospholipids, as revealed by an enhanced formation of [3H]inositolmonophosphate ([3H]InsP) in the presence of 10 mM Li+. This increase was prevented by the muscarinic receptor antagonist, atropine, or by tetrodotoxin, but not by other receptor antagonists, such as L-2-amino-4-phosphonobutanoate (L-AP4), prazosin or ketanserin. The increase in inositol phospholipid hydrolysis induced by repeated addition of CDP-choline was obliterated when cultures were incubated in the presence of the muscarinic receptor agonist, carbamylcholine. CDP-choline had no effect on inositol phospholipid hydrolysis in cultured cerebellar neurons, which are devoid of cholinergic cells. The basal hydrolysis of inositol phospholipids was also increased in hippocampal slices prepared from rats repeatedly injected with CDP-choline (200 mg/kg, i.p. for 15 days). As observed in cultured cortico-striatal neurons, this increase was prevented by atropine and was masked in the presence of carabamylcholine. Taken collectively, these data indicate that repeated exposure to exogenous CDP-choline increases polyphosphoinositide turnover, an effect that results from an increased availability of acetylcholine acting on muscarinic receptors.


Asunto(s)
Encéfalo/efectos de los fármacos , Citidina Difosfato Colina/farmacología , Fosfatidilinositoles/metabolismo , Receptores Muscarínicos/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Acetilcolina/fisiología , Animales , Encéfalo/fisiología , Cerebelo/efectos de los fármacos , Cerebelo/fisiología , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/fisiología , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/fisiología , Técnicas de Cultivo , Hidrólisis , Neuronas/efectos de los fármacos , Neuronas/fisiología , Ratas , Receptores Muscarínicos/fisiología , Transmisión Sináptica/fisiología
18.
J Neurochem ; 58(4): 1199-204, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1372342

RESUMEN

Micromolar concentrations of piracetam, aniracetam, and oxiracetam enhanced alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-stimulated 45Ca2+ influx in primary cultures of cerebellar granule cells. Nootropic drugs increased the efficacy but not the potency of AMPA and their action persisted in the presence of the voltage-sensitive calcium channel blocker nifedipine. Potentiation by oxiracetam was specific for AMPA receptor-mediated signal transduction, as the drug changed neither the stimulation of 45Ca2+ influx by kainate or N-methyl-D-aspartate nor the activation of inositol phospholipid hydrolysis elicited by quisqualate or (+-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid. Piracetam, aniracetam, and oxiracetam increased the maximal density of the specific binding sites for [3H]AMPA in synaptic membranes from rat cerebral cortex. Taken collectively, these results support the view that nootropic drugs act as positive modulators of AMPA-sensitive glutamate receptors in neurons.


Asunto(s)
Ácido Iboténico/análogos & derivados , Neuronas/metabolismo , Psicotrópicos/farmacología , Receptores de Neurotransmisores/efectos de los fármacos , Animales , Calcio/metabolismo , Células Cultivadas , Corteza Cerebral/citología , Corteza Cerebral/metabolismo , Glutamatos/metabolismo , Ácido Iboténico/farmacología , Cinética , Modelos Neurológicos , Receptores de Glutamato , Receptores de Neurotransmisores/metabolismo , Membranas Sinápticas/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico
19.
Acta Neurol (Napoli) ; 14(1): 15-21, 1992 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1580200

RESUMEN

Daily addition of acetyl-L-carnitine (100 microM) to cultured cerebellar granule cells since the first day of maturation led to an increased rate of expression of D-[3H]aspartate uptake (an established marker of maturation of glutamatergic neurons) and of N-methyl-D-aspartate (NMDA) receptors linked to large conductance ion channels permeable to Ca2+. Acetyl-L-carnitine treatment also increased neuronal survival, as reflected by a greater percentage of cultures retaining functional NMDA receptors after 15 days of maturation. These results support the view that acetyl-L-carnitine exerts neuronotrophic activity and prevents age-dependent neuronal degeneration.


Asunto(s)
Acetilcarnitina/farmacología , Neuronas/efectos de los fármacos , Animales , Células Cultivadas , Senescencia Celular/efectos de los fármacos , Cerebelo/citología , Degeneración Nerviosa/efectos de los fármacos , Neuronas/metabolismo , Ratas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA