Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
1.
Clin Exp Rheumatol ; 27(1): 7-14, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19327223

RESUMEN

OBJECTIVE: The aim of the present study was to investigate the long-term efficacy of a 3-week intensive residential multidisciplinary non-pharmacological treatment program (including individually prescribed and monitored aerobic exercise and cognitive behavioural therapy) on fibromyalgia symptoms and aerobic fitness. METHODS: Twenty-five women with fibromyalgia participated in six experimental sessions (pre-admission, immediately before and immediately after the treatment, and to 2, 5 and 12 months afterwards) in which they underwent clinical, psychophysical and psychological examinations: pain intensity (VAS), pain area (percentage of total body surface), deep pressure pain threshold at 18 tender point sites measured with a pressure algometer, an incremental step test with blood lactate determination and calculation of the individual intensity of exercise corresponding to 2 mM of lactate concentration (W2, index of aerobic fitness). Depression and coping were evaluated with the Center for Epidemiologic Studies Depression Scale (CES-D) and Brief Pain Coping Inventory (BPCI), respectively. RESULTS: Pain intensity, pain area and number of positive tender points were significantly reduced up to 12 months, while deep pressure pain threshold and W2 increased. CES-D score decreased until two months. Among the 18 items of the BCPI, only item 3 ("physical exercise/stretching") changed significantly, increasing until 12 months. CONCLUSION: In fibromyalgia patients, whose symptoms before treatment were constant, a 3-week intensive residential multidisciplinary treatment program showed one-year efficacy in improving pain and aerobic fitness. The acquisition of physical exercise as a coping strategy for chronic pain acceptance could explain the long-term effects of our brief treatment.


Asunto(s)
Terapia Cognitivo-Conductual , Terapia por Ejercicio/métodos , Fibromialgia/terapia , Terapia por Relajación , Adaptación Psicológica , Adulto , Terapia Combinada , Depresión/complicaciones , Depresión/terapia , Ejercicio Físico , Femenino , Fibromialgia/psicología , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Dolor/psicología , Manejo del Dolor , Dimensión del Dolor , Índice de Severidad de la Enfermedad
4.
J Biol Chem ; 270(36): 20942-51, 1995 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-7673118

RESUMEN

In bovine adrenal zona fasciculata (AZF) cells, angiotensin II (AII) may stimulate depolarization-dependent Ca2+ entry and cortisol secretion through inhibition of a novel potassium channel (IAC), which appears to set the resting potential of these cells. Aspects of the signaling pathway, which couples AII receptors to membrane depolarization and secretion, were characterized in patch clamp and membrane potential recordings and in secretion studies. AII-mediated inhibition of IAC, membrane depolarization, and cortisol secretion were all blocked by the AII type I (AT1) receptor antagonist losartan. These responses were unaffected by the AT2 antagonist PD123319. Inhibition of IAC by AII was prevented by intracellular application of guanosine 5'-O-2-(thio)-diphosphate but was not affected by pre-incubation of cells with pertussis toxin. Although mediated through an AT1 receptor, several lines of evidence indicated that AII inhibition of IAC occurred through an unusual phospholipase C (PLC)-independent pathway. Acetylcholine, which activates PLC in AZF cells, did not inhibit IAC. Neither the PLC antagonist neomycin nor PLC-generated second messengers prevented IAC expression or mimicked the inhibition of this current by AII. IAC expression and inhibition by AII were insensitive to variations in intracellular or extracellular Ca2+ concentration. AII-mediated inhibition of IAC was markedly reduced by the non-hydrolyzable ATP analog adenosine 5'-(beta, gamma-imino)triphosphate and by the non-selective protein kinase inhibitor staurosporine. The protein phosphatase antagonist okadaic acid reversibly inhibited IAC in whole cell recordings. These findings indicate that AII-stimulated effects on IAC current, membrane voltage, and cortisol secretion are linked through a common AT1 receptor. Inhibition of IAC in AZF cells appears to occur through a novel signaling pathway, which may include a losartan-sensitive AT1 receptor coupled through a pertussis-insensitive G protein to a staurosporine-sensitive protein kinase. Apparently, the mechanism linking AT1 receptors to IAC inhibition and Ca2+ influx in adrenocortical cells is separate from that involving inositol trisphosphate-stimulated Ca2+ release from intracellular stores. AII-stimulated cortisol secretion may occur through distinct parallel signaling pathways.


Asunto(s)
Glándulas Suprarrenales/metabolismo , Compuestos de Bifenilo/farmacología , Hidrocortisona/metabolismo , Imidazoles/farmacología , Receptores de Angiotensina/metabolismo , Transducción de Señal , Tetrazoles/farmacología , Glándulas Suprarrenales/fisiología , Angiotensina II/farmacología , Animales , Bovinos , Activación Enzimática , Proteínas de Unión al GTP/metabolismo , Nucleótidos de Guanina/metabolismo , Técnicas In Vitro , Activación del Canal Iónico , Losartán , Potenciales de la Membrana , Fosfolipasas/metabolismo , Fosforilación , Bloqueadores de los Canales de Potasio , Proteínas Quinasas/metabolismo , Receptores de Angiotensina/efectos de los fármacos
5.
J Gen Physiol ; 102(2): 217-37, 1993 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8228909

RESUMEN

The whole cell version of the patch clamp technique was used to identify and characterize voltage-gated Ca2+ channels in enzymatically dissociated bovine adrenal zona fasciculata (AZF) cells. The great majority of cells (84 of 86) expressed only low voltage-activated, rapidly inactivating Ca2+ current with properties of T-type Ca2+ current described in other cells. Voltage-dependent activation of this current was fit by a Boltzmann function raised to an integer power of 4 with a midpoint at -17 mV. Independent estimates of the single channel gating charge obtained from the activation curve and using the "limiting logarithmic potential sensitivity" were 8.1 and 6.8 elementary charges, respectively. Inactivation was a steep function of voltage with a v1/2 of -49.9 mV and a slope factor K of 3.73 mV. The expression of a single Ca2+ channel subtype by AZF cells allowed the voltage-dependent gating and kinetic properties of T current to be studied over a wide range of potentials. Analysis of the gating kinetics of this Ca2+ current indicate that T channel activation, inactivation, deactivation (closing), and reactivation (recovery from inactivation) each include voltage-independent transitions that become rate limiting at extreme voltages. Ca2+ current activated with voltage-dependent sigmoidal kinetics that were described by an m4 model. The activation time constant varied exponentially at test potentials between -30 and +10 mV, approaching a voltage-independent minimum of 1.6 ms. The inactivation time constant (tau i) also decreased exponentially to a minimum of 18.3 ms at potentials positive to 0 mV. T channel closing (deactivation) was faster at more negative voltages; the deactivation time constant (tau d) decreased from 8.14 +/- 0.7 to 0.48 +/- 0.1 ms at potentials between -40 and -150 mV. T channels inactivated by depolarization returned to the closed state along pathways that included two voltage-dependent time constants. tau rec-s ranged from 8.11 to 4.80 s when the recovery potential was varied from -50 to -90 mV, while tau rec-f decreased from 1.01 to 0.372 s. At potentials negative to -70 mV, both time constants approached minimum values. The low voltage-activated Ca2+ current in AZF cells was blocked by the T channel selective antagonist Ni2+ with an IC50 of 20 microM. At similar concentrations, Ni2+ also blocked cortisol secretion stimulated by adrenocorticotropic hormone. Our results indicate that bovine AZF cells are distinctive among secretory cells in expressing primarily or exclusively T-type Ca2+ channels.(ABSTRACT TRUNCATED AT 400 WORDS)


Asunto(s)
Canales de Calcio/fisiología , Activación del Canal Iónico/fisiología , Zona Fascicular/citología , Zona Fascicular/fisiología , Animales , Bovinos , Membrana Celular/fisiología , Membrana Celular/ultraestructura , Células Cultivadas , Potenciales de la Membrana/fisiología , Níquel/farmacología , Zona Fascicular/ultraestructura
6.
J Biol Chem ; 268(12): 8640-4, 1993 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-8386167

RESUMEN

Adrenocorticotropic hormone (ACTH) and angiotensin II (AII) are peptides that regulate the production of steroid hormones by cells of the adrenal cortex. The cellular mechanisms linking these peptides to corticosteroid hormone secretion are not understood. In patch clamp recordings from bovine adrenal zona fasciculata (AZF) cells, we have identified a novel cholera toxin-sensitive K+ current (IAC), which is potently inhibited by both ACTH and AII with respective EC50 values of 4.5 and 145 pM. These two peptides depolarize AZF cells with a temporal pattern and potency that parallels the inhibition of IAC. With the discovery of IAC, we have identified a common molecular target for both ACTH and AII. The convergent inhibition of IAC by these two peptides suggests a mechanism whereby biochemical signals originating at the cell membrane can be transduced to depolarization-dependent Ca2+ entry and steroid hormone secretion.


Asunto(s)
Corteza Suprarrenal/metabolismo , Hormona Adrenocorticotrópica/farmacología , Angiotensina II/farmacología , Canales de Potasio/metabolismo , Corteza Suprarrenal/citología , Corticoesteroides/metabolismo , Animales , Bovinos , Células Cultivadas , Cinética , Potenciales de la Membrana , Potasio/metabolismo
7.
Thorac Cardiovasc Surg ; 41(1): 16-20, 1993 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8103610

RESUMEN

An histological comparison was made between left internal mammary arteries (LIMAs) harvested and prepared with different techniques prior to coronary artery bypass grafting. The mobilization of LIMA was made as follows: conventional technique (group I), extra pleural takedown with lysis of the endothoracic fascia (group II), and LIMA skeletonization (group III). Each group was divided into two other sub-groups according to the LIMA graft preparation: papaverine-saline solution sprayed on the pedicle (sub-group A) and intraluminal hydrostatic dilatation (sub-group B). Free blood flow from the LIMAs was measured immediately before cardiopulmonary bypass and ultrasonic duplex scanning (UDS) was performed to analyze the flow patterns and velocities during the early postoperative course. The results showed that the technique by which the LIMA is harvested bears no significant relationship to microscopical graft damage, while intimal lesions were observed in all sub-groups that adopted intraluminal hydrostatic dilatation (sub-group B). No difference in intraoperative LIMA flows were noted between groups and sub-groups of patients except in the case of group I-sub-group B, in which the flow was markedly reduced. Intramural haematoma or subadventitial blood effusion was observed with low incidence and magnitude in all groups and subgroups of patients, without any reduction of blood flow, and all LIMAs were patent at UDS measurements. In conclusion, the results showed that the method by which the IMA is harvested bears little and insignificant relationship to arterial wall damage.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Arterias Mamarias/patología , Revascularización Miocárdica/métodos , Anciano , Velocidad del Flujo Sanguíneo , Puente de Arteria Coronaria/métodos , Femenino , Técnicas Histológicas , Humanos , Periodo Intraoperatorio , Masculino , Arterias Mamarias/diagnóstico por imagen , Arterias Mamarias/fisiopatología , Persona de Mediana Edad , Ultrasonografía , Grado de Desobstrucción Vascular
8.
Am J Physiol ; 263(5 Pt 1): C986-94, 1992 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-1443107

RESUMEN

The whole cell version of the patch-clamp technique was used to identify and characterize voltage-gated Ca2+, Na+, and K+ currents in the calcitonin-secreting human thyroid TT cell line. Ca2+ current consisted of a single low-voltage-activated rapidly inactivating component. The current was one-half maximally activated at a potential of -27 mV, while steady-state voltage-dependent inactivation was one-half complete at -51 mV. The Ca2+ current inactivated with a voltage-dependent time constant that reached a minimum of 16 ms at potentials positive to -15 mV. Deactivation kinetics could also be fit with a single voltage-dependent time constant of approximately 2 ms at -80 mV. Replacing Ca2+ with Ba2+ reduced the maximum current by 18 +/- 5% (n = 6). The dihydropyridine Ca2+ agonist (-)BAY K 8644 did not affect the Ca2+ current, but 50 microM Ni2+ reduced it by 81 +/- 0.8% (n = 5). TT cells also possessed tetrodotoxin-sensitive voltage-gated Na+ channels and tetraethylammonium-sensitive delayed rectifier type K+ currents. These results indicate that TT cells possess membrane currents necessary for the generation of action potentials. T-type Ca2+ channels are the sole pathway for voltage-dependent Ca2+ entry into these cells and may couple electrical activity to calcitonin secretion.


Asunto(s)
Calcitonina/metabolismo , Carcinoma/fisiopatología , Neoplasias de la Tiroides/fisiopatología , Carcinoma/metabolismo , Carcinoma/patología , Electrofisiología , Humanos , Cinética , Potasio/fisiología , Sodio/fisiología , Tetrodotoxina/farmacología , Neoplasias de la Tiroides/metabolismo , Neoplasias de la Tiroides/patología , Células Tumorales Cultivadas
9.
Mol Pharmacol ; 42(2): 364-72, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1355264

RESUMEN

We have used the whole-cell version of the patch-clamp technique to analyze the inhibition of Ca2+ currents by antipsychotic agents in neural crest-derived rat and human thyroid C cell lines. Diphenylbutylpiperidine (DPBP) antipsychotics, including penfluridol and fluspirilene, potently and preferentially block T-type Ca2+ current in the rat medullary thyroid carcinoma 6-23 (clone 6) cell line. When step depolarizations were applied at 0.1 Hz from a holding potential of -80 mV, with 10 mM Ca2+ as the charge carrier, the DPBP penfluridol inhibited T-type current with an IC50 of 224 nM. High voltage-activated L and N currents were less potently blocked. At a concentration of 500 nM, penfluridol inhibited 78.0 +/- 2.3% (n = 29) of inactivating T-type Ca2+ current, whereas the sustained high voltage-activated current was reduced by 25.6 +/- 3.5% (n = 28). Block of T-type current by penfluridol was enhanced by depolarizing test pulses applied at frequencies above 0.03 Hz. The use-dependent component of block was largely reversed by pulse-free periods at -80 mV. T-type Ca2+ channels in the human TT C cell line were blocked by penfluridol, and the potency was enhanced by reduction of extracellular Ca2+. Non-DPBP antipsychotics, including haloperidol, clozapine, and thioridazine, also blocked T-type channels, but these were 20-100 times less potent than the DPBPs. These results identify the DPBPs as a new class of organic Ca2+ channel antagonists, which are distinctive in their ability to preferentially block T-type channels. These agents will be useful in defining the function of T channels in various excitable cells. Their potent block of T-type Ca2+ channels, which would be enhanced in rapidly firing cells, suggests that this action may be relevant to the therapeutic or toxic effects of these drugs when used in clinical pharmacology.


Asunto(s)
Antipsicóticos/farmacología , Bloqueadores de los Canales de Calcio/farmacología , Cresta Neural/efectos de los fármacos , Animales , Canales de Calcio/fisiología , Electrofisiología , Humanos , Potenciales de la Membrana/efectos de los fármacos , Cresta Neural/patología , Cresta Neural/fisiología , Penfluridol/farmacología , Ratas , Neoplasias de la Tiroides/patología , Neoplasias de la Tiroides/fisiopatología , Células Tumorales Cultivadas/efectos de los fármacos
10.
Am J Physiol ; 262(5 Pt 1): G940-4, 1992 May.
Artículo en Inglés | MEDLINE | ID: mdl-1590403

RESUMEN

In a previous study [B. Biagi, Y.-Z. Wang, and H. J. Cooke, Am. J. Physiol. 258 (Gastrointest. Liver Physiol. 21): G223-G230, 1990], carbachol stimulated active chloride transport in rabbit distal colon, yet had no effect on the basolateral membrane potential (Vbl) of cells from isolated crypts from the same tissue. In the present study, crypt cells were first depolarized with vasoactive intestinal peptide (VIP; 1 x 10(-9) M) (control Vbl = -62 mV; VIP Vbl = -48 mV) and then exposed to carbachol in the presence of VIP. The VIP-induced depolarization of Vbl was completely reversed by carbachol (0.1 mM; repolarization to -65 mV). Similar repolarization was seen by applying carbachol to crypt cells depolarized by 10 mM aminophylline. Intracellular K+ activity (aiK), measured with K(+)-selective microelectrodes, was 64.3 mM (concn = 85 mM), yielding a K+ equilibrium potential (EK+) of -76 mV. Neither carbachol nor VIP application caused significant changes in aiK. These results demonstrate the presence of cholinergic receptors on colonic crypt cells. The magnitude of the carbachol effect on Vbl is greater when Vbl is depolarized relative to EK+. The results are consistent with the hypothesis that carbachol acts by increasing basolateral K+ conductance, driving the cell toward the EK+.


Asunto(s)
Carbacol/farmacología , Colon/efectos de los fármacos , Mucosa Intestinal/efectos de los fármacos , Péptido Intestinal Vasoactivo/farmacología , Animales , Colon/citología , Colon/fisiología , Interacciones Farmacológicas , Técnicas In Vitro , Mucosa Intestinal/citología , Mucosa Intestinal/fisiología , Potenciales de la Membrana , Conejos
11.
Mol Endocrinol ; 6(4): 563-71, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1374838

RESUMEN

We have studied the interaction between dihydropyridine (DHP) Ca2+ modulators and the phorbol ester phorbol 12-myristate 13-acetate (PMA) on whole cell Ca2+ currents, 45Ca2+ uptake, immediate early gene (IEG) expression, and proliferation in the rat pituitary GH4C1 cell line. When short (3- to 5-msec) depolarizing voltage clamp steps were used to activate L-type Ca2+ channels, the DHP Ca2+ agonist (-)Bay K 8644 markedly enhanced Ca2+ entry by slowing channel closing upon repolarization. In contrast, the Ca2+ agonist induced only small and inconsistent increases in c-fos mRNA and did not measurably increase NGFI-A. Ca2+ channel activation by depolarization with 50 mM KCl in the presence of (-)Bay K 8644 induced large increases in 45Ca2+ uptake, but failed to markedly induce either of the IEGs. The phorbol ester PMA did not alter T- or L-type Ca2+ current or 45Ca2+ uptake by GH4C1 cells, but triggered large increases in both c-fos and NGFI-A mRNA. In combination, PMA and (-)Bay K 8644 acted synergistically to increase mRNAs for both IEGs. The effect of the DHPs was stereospecific; (+)Bay K 8644, a Ca2+ antagonist, inhibited PMA-induced increases in c-fos and NGFI-A mRNAs. Both PMA and (-)Bay K 8644 inhibited the proliferation of GH4C1 cells, measured by cell count or [3H]thymidine incorporation. The inhibition by the Ca2+ agonist was stereoselective and approximately additive to that of PMA. These results indicate that the expression of c-fos IEG and that of NGFI-A IEG are differentially regulated by separate second messenger pathways in GH4C1 cells.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Ácido 3-piridinacarboxílico, 1,4-dihidro-2,6-dimetil-5-nitro-4-(2-(trifluorometil)fenil)-, Éster Metílico/farmacología , Canales de Calcio/fisiología , Calcio/metabolismo , Genes Reguladores/efectos de los fármacos , Proteína Quinasa C/metabolismo , Acetato de Tetradecanoilforbol/farmacología , Animales , Canales de Calcio/efectos de los fármacos , División Celular/efectos de los fármacos , Línea Celular , Replicación del ADN/efectos de los fármacos , Activación Enzimática , Genes fos/efectos de los fármacos , Isomerismo , Cinética , Potenciales de la Membrana/efectos de los fármacos , Neoplasias Hipofisarias , ARN Mensajero/genética , ARN Mensajero/metabolismo , Timidina/metabolismo
12.
Ann Thorac Surg ; 52(6): 1292-4, 1991 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1684491

RESUMEN

Four hundred thirty-three patients underwent coronary bypass grafting using both internal mammary artery (IMA) and saphenous vein graft. In 233 patients the IMA was exposed with a conventional technique (group 1), whereas in the remaining patients the IMA was harvested leaving the pleura intact and performing an associated lysis of the endothoracic fascia (group 2). Postoperative course and complications of these groups were studied and compared in a period of time ranging from 8 to 28 months. Postoperatively, the blood transfused was significantly less in group 2 patients than in group 1; group 2 also had a reduction of surgical reexploration. Pleural effusion and hemidiaphragm impairment were infrequent or absent in group 2 patients, whereas pericarditis, severe postoperative chest pain, and respiratory insufficiency were noted only in group 1 patients. Our data suggest that extrapleural access without pleurotomy may be preferred owing to its low rate of chest wall complications.


Asunto(s)
Arterias Mamarias/cirugía , Revascularización Miocárdica/métodos , Pleura/cirugía , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Distribución Aleatoria
13.
Resuscitation ; 22(2): 123-7, 1991 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-1661017

RESUMEN

Spontaneous rupture of one or more cardiac chambers following open heart surgery is not common. A case is reported of a 45 year-old woman who sustained a spontaneous rupture of the right atrium in the intensive care unit after mitral valve replacement. Exsanguination of the patient was very rapid. On the basis of clinical and experimental convincing studies in this case a high dose of ACTH was used to prevent the damaging effect of haemorrhagic shock. During the reopening manoeuvre and initial conventional management, 10 mg ACTH (1-24) was injected into a peripheral vein. Although the blood lost was 93% of her circulating blood volume and a lot of fluid transfused via the central venous catheter was lost into the pericardium and hemithorax, the patient's condition improved rapidly after the occlusion of the atrial tear with initial small volume of transfusion. Based on the review of recent investigations the use of ACTH is emphasized.


Asunto(s)
Hormona Adrenocorticotrópica/uso terapéutico , Prótesis Valvulares Cardíacas , Complicaciones Posoperatorias/tratamiento farmacológico , Choque Hemorrágico/tratamiento farmacológico , Femenino , Atrios Cardíacos , Rotura Cardíaca/complicaciones , Humanos , Persona de Mediana Edad , Válvula Mitral , Estenosis de la Válvula Mitral/cirugía , Fragmentos de Péptidos/uso terapéutico , Choque Hemorrágico/etiología
14.
Am J Physiol ; 260(6 Pt 1): C1253-63, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-1647663

RESUMEN

The whole cell version of the patch-clamp technique was used to characterize voltage-gated Ca2+ channels in the calcitonin-secreting rat thyroid C-cell line 6-23 (clone 6). Three types of Ca2+ channels could be distinguished based on differences in voltage dependence, kinetics, and pharmacological sensitivity. T-type current was half-maximal at -31 mV, showed steady-state voltage-dependent inactivation that was half-maximal at -57 mV, inactivated with a voltage-dependent time constant that reached a minimum of 20 ms at potentials positive to -20 mV, and deactivated with a single time constant of approximately 2 ms at -80 mV. Reactivation of inactivated channels occurred with a time constant of 1.26 s at -90 mV. T current was selectively blocked by Ni2+ at concentrations between 5 and 50 microM. La3+ and Y3+ blocked the T current at 10- to 20-fold lower concentrations. Dihydropyridine-sensitive L-type current was half-maximal at a test potential of -3 mV and was approximately doubled in size when Ba2+ replaced Ca2+ as the charge carrier. Unlike L-type Ca2+ current in many cells, this current in C-cells displayed little Ca(2+)-dependent inactivation. N-type current was composed of inactivating and sustained components that were inhibited by omega-conotoxin. The inactivating component was half-maximal at +9 mV and could be fitted by two exponentials with time constants of 22 and 142 ms. A slow inactivation of N current with a time constant of 24.9 s was observed upon switching the holding potential from -80 to -40 mV. These results demonstrate that, similar to other neural crest derived cells, thyroid C-cells express multiple Ca2+ channels, including one previously observed only in neurons.


Asunto(s)
Canales de Calcio/fisiología , omega-Conotoxinas , Animales , Bario/farmacología , Calcio/farmacología , Canales de Calcio/efectos de los fármacos , Línea Celular , Cinética , Potenciales de la Membrana/efectos de los fármacos , Nimodipina/farmacología , Péptidos Cíclicos/farmacología , Ratas , Neoplasias de la Tiroides
15.
Ann Thorac Surg ; 51(2): 320-2, 1991 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1989557

RESUMEN

Tricuspid valve incompetence from ruptured papillary muscle or chordae as a result of nonpenetrating trauma is uncommon. Blunt trauma causing partial detachment of a leaflet from the annulus is very rare. We report the case of a young adult involved in a car accident who had these findings. Operative repair with resuture of the leaflet to the annulus and annuloplasty using a Carpentier ring resulted in complete recovery.


Asunto(s)
Músculos Papilares/lesiones , Insuficiencia de la Válvula Tricúspide/etiología , Heridas no Penetrantes/complicaciones , Adulto , Humanos , Masculino , Insuficiencia de la Válvula Tricúspide/cirugía
16.
J Biol Chem ; 265(27): 16373-9, 1990 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-1697857

RESUMEN

The effects of diphenylbutylpiperidine (DPBP) antipsychotics on Ca2+ currents and prolactin (PRL) synthesis were studied in rat pituitary growth hormone (GH) cell lines (GH3 and GH4C1). In whole-cell patch-clamp experiments, DPBPs including fluspirilene, penfluridol, and pimozide at concentrations ranging from 0.25 to 5 microM each blocked current through low threshold T-type as well as high threshold L-type channels. Each of the drugs preferentially blocked T-type current, and complete inhibition was observed at concentrations as low as 1 microM. Inhibition of L-type channels by DPBPS was enhanced at depolarized holding potentials and promoted by prolonged channel activation. At concentrations similar to those which blocked Ca2+ currents, each of the three DPBPs markedly reduced basal PRL production by GH cells. PRL synthesis stimulated by the dihydropyridine Ca2+ agonist R5417 or thyrotropin releasing hormone (TRH) was also inhibited. The inhibitory effects of the DPBPs were observed at the level of gene transcription. Penfluridol and fluspirilene inhibited basal, Ca2(+)- and TRH-stimulated expression of a fusion gene construct containing the 5'-flanking sequence of the rat PRL gene linked to the luciferase gene. The effect was concentration-dependent with the IC50 values for both drugs of less than 1 microM. Nimodipine also reduced basal, R5417, and TRH-stimulated expression of the reporter gene construct. Similar results were obtained with a reporter gene construct containing the 5'-flanking sequence of the rat GH gene. The GH luciferase construct was only slightly responsive to R5417 and TRH; however, these responses were reduced by fluspirilene and nimodipine at concentrations of less than 1 microM. These studies demonstrate that the DPBP antipsychotics block T- as well as L-type Ca2+ channels in GH cells and inhibit PRL production at the level of transcription. They also indicate that functioning Ca2+ channels are necessary for TRH-stimulated PRL gene transcription.


Asunto(s)
Canales de Calcio/fisiología , Fluspirileno/farmacología , Expresión Génica/efectos de los fármacos , Penfluridol/farmacología , Pimozida/farmacología , Piperidinas/farmacología , Prolactina/genética , Compuestos de Espiro/farmacología , Ácido 3-piridinacarboxílico, 1,4-dihidro-2,6-dimetil-5-nitro-4-(2-(trifluorometil)fenil)-, Éster Metílico/farmacología , Animales , Canales de Calcio/efectos de los fármacos , Línea Celular , Cinética , Luciferasas/biosíntesis , Luciferasas/genética , Potenciales de la Membrana/efectos de los fármacos , Neoplasias Hipofisarias , Prolactina/biosíntesis , Proteínas Recombinantes de Fusión/biosíntesis , Hormona Liberadora de Tirotropina/farmacología
17.
Am J Physiol ; 259(3 Pt 1): C515-20, 1990 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-2169198

RESUMEN

The inhibition of L- and T-type Ca2+ currents by Gd3+ was studied in the rat pituitary GH4C1 cell line. In whole cell patch recordings, Gd3+ at concentrations of 50 nM to 5 microM blocked Ca2+ current through L-type channels. Block was promoted by prolonged channel activation. With 4.5-s test pulses to + 10 mV, Gd3+ at concentrations as low as 200 nM produced near-complete block of L current. At higher Gd3+ concentrations (5 microM), complete block occurred with short test pulses and appeared to be independent of channel activation. Gd3+ also blocked current through low-threshold T channels in GH4C1 cells. Two other trivalent elements, La3+ and Y3+, blocked L-type Ca2+ channels in GH4C1 cells with potency similar to Gd3+. These results indicate that these trivalent cations are effective nonselective inhibitors of both low- and high-threshold Ca2+ channels in endocrine cells. In this regard, they are among the most potent inorganic Ca2+ antagonists yet discovered.


Asunto(s)
Canales de Calcio/fisiología , Calcio/metabolismo , Gadolinio/farmacología , Animales , Canales de Calcio/efectos de los fármacos , Línea Celular , Ácido Egtácico/farmacología , Cinética , Lantano/farmacología , Potenciales de la Membrana/efectos de los fármacos , Neoplasias Hipofisarias , Itrio/farmacología
18.
Mol Endocrinol ; 4(5): 727-35, 1990 May.
Artículo en Inglés | MEDLINE | ID: mdl-1703274

RESUMEN

Dihydropyridine (DHP) Ca2+ channel modulators were used to explore the relationship between voltage-gated Ca2+ channels and PRL secretion, synthesis, and mRNA in PRL-secreting pituitary cells. Optical isomers of the Ca2+ channel agonist Bay K 8644 produced stereospecific and opposing effects on L-type Ca2+ current, PRL release, and synthesis in GH3 and GH4C1 cells. (-)-Bay K 8644 (R5417) behaved as a pure agonist, enhancing Ca2+ current several-fold while shifting the current-voltage curve 10-15 mV in the hyperpolarizing direction. The agonist effect was independent of holding potential, but decreased during prolonged Ba2+ or Ca2+ entry. R5417 produced a concentration-dependent increase in acute PRL release and enhanced PRL production by GH cells several-fold during a 72-h period. (+)-Bay K 8644 (R4407) behaved as a weak Ca2+ channel antagonist, inhibiting L-type Ca2+ current, KCl-stimulated PRL secretion, and PRL production at concentrations of 0.5-5 microM. These two isomers produced similar effects on PRL production by normal rat pituitary cells in dispersed culture. R5417 (500 nM) increased PRL produced in 72 h to 233 +/- 8% of the control value. R4407 reduced this quantity by 36 +/- 9%. The effects of the DHPs on PRL mRNA levels were consistent with the effects observed for acute secretion and hormone production. The agonist R5417 increased PRL mRNA 147 +/- 5% over a 30-h period, and the potent DHP Ca2+ channel blocker nimodipine inhibited PRL mRNA production 2-fold. These results demonstrate that racemic Bay K 8644 interacts with L-type Ca2+ channels in normal and transformed pituitary cells as a mixed agonist-antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Ácido 3-piridinacarboxílico, 1,4-dihidro-2,6-dimetil-5-nitro-4-(2-(trifluorometil)fenil)-, Éster Metílico/farmacología , Canales de Calcio/efectos de los fármacos , Prolactina/metabolismo , Animales , Línea Celular , Electroquímica , Hipófisis/efectos de los fármacos , Hipófisis/metabolismo , Prolactina/biosíntesis , Prolactina/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Estereoisomerismo
19.
Am J Physiol ; 258(2 Pt 1): G223-30, 1990 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2305888

RESUMEN

The effects of tetrodotoxin (TTX) were examined in muscle-stripped segments of rabbit distal colon and in cells of isolated colonic crypts. Electrical field stimulation (EFS) of the submucosa/mucosa evoked an increase in short-circuit current (ISC) that was due to an increase in chloride secretion. The EFS-evoked response was reduced 81% by 10(-7) M TTX and 30% by 5 X 10(-6) M atropine. Vasoactive intestinal peptide (VIP), carbachol, aminophylline, and 1,1-dimethyl-4-phenylpiperazinium increased ISC. Bumetanide reduced the responses to neural stimulation, aminophylline, and VIP. To determine whether TTX had direct effects on crypt epithelial cells, crypts were isolated and cells were impaled with microelectrodes. Mean resting potential (Vbl) was -67 +/- 1.1 mV (n = 63). VIP and aminophylline depolarized Vbl by 34 +/- 4.6 (n = 13) and 34 +/- 3.5 mV (n = 18), respectively. TTX had no significant effect on resting Vbl or on the responses to VIP or aminophylline. We conclude that stimulation of submucosal neurons in the rabbit distal colon evokes a TTX- and bumetanide-sensitive increase in net chloride secretion that is dependent on the release of acetylcholine and other secretory neurotransmitters. Electrophysiological studies rule out a direct effect of TTX on colonic crypt cells.


Asunto(s)
Cloruros/metabolismo , Colon/fisiología , Mucosa Intestinal/efectos de los fármacos , Tetrodotoxina/farmacología , Amilorida/farmacología , Aminofilina/farmacología , Animales , Bumetanida/farmacología , Carbacol/farmacología , Colon/efectos de los fármacos , Yoduro de Dimetilfenilpiperazina/farmacología , Conductividad Eléctrica , Estimulación Eléctrica , Epitelio/efectos de los fármacos , Epitelio/fisiología , Femenino , Técnicas In Vitro , Mucosa Intestinal/fisiología , Potenciales de la Membrana/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Conejos , Péptido Intestinal Vasoactivo/farmacología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA