RESUMEN
Although increased levels of C-reactive protein have been linked to E therapy, the significance of this finding and whether it occurs with the selective ER modulators are unknown. Thirty-five healthy postmenopausal women were enrolled in a placebo-controlled, two-period cross-over design trial to evaluate the effects of 0.625 mg oral conjugated E and 60 mg droloxifene, a structural analog of tamoxifen, on serum levels of C-reactive protein, IL-6, and endothelial cell adhesion molecules. E treatment resulted in 65.8% higher levels of C-reactive protein (P = 0.0002) and 48.1% higher levels of IL-6 (P < 0.001), but also resulted in a 10.9% reduction in soluble E-selectin (P = 0.002) and borderline reductions in vascular cell adhesion molecule-1. In contrast, droloxifene had no effect on C-reactive protein and IL-6, but did produce a significant 11% reduction in E-selectin (P < 0.00001). However, droloxifene also resulted in an 11.6% increase in vascular cell adhesion molecule-1 (P < 0.007). These data provide additional evidence of a proinflammatory effect of E that may have adverse cardiovascular consequences. However, these changes were also accompanied by a reduction in E-selectin, suggesting an antiinflammatory effect at the level of the endothelium. The net clinical impact of these changes is not yet well established. In contrast, droloxifene had little or no proinflammatory effects on C-reactive protein and IL-6 and had mixed effects on endothelial adhesion molecules. This observation provides additional rationale for continuing to evaluate the potential cardiovascular benefits of selective ER modulators.
Asunto(s)
Proteína C-Reactiva/metabolismo , Terapia de Reemplazo de Estrógeno , Inflamación/sangre , Posmenopausia/sangre , Moduladores Selectivos de los Receptores de Estrógeno/uso terapéutico , Tamoxifeno/uso terapéutico , Proteínas de Fase Aguda/metabolismo , Anciano , Biomarcadores , Índice de Masa Corporal , Moléculas de Adhesión Celular/metabolismo , Estudios Cruzados , Método Doble Ciego , Femenino , Humanos , Interleucina-6/sangre , Persona de Mediana Edad , Tamoxifeno/análogos & derivadosRESUMEN
OBJECTIVE: Reduced muscle mass and strength are characteristic findings of growth hormone deficiency (GHD) and aging. We evaluated measures of muscle strength, muscle fiber type, and cross sectional area in response to treatment with recombinant human growth hormone (rhGH) with or without a structured resistance exercise program in frail older subjects. DESIGN: Placebo-controlled, randomized, double blind trial. SETTING: Outpatient clinical research center at an urban university-affiliated teaching hospital. PARTICIPANTS: Thirty-one consenting older subjects (mean age 71.3 +/- 4.5 years) recruited as a subset of a larger project evaluating rhGH and exercise in older people, who underwent 62 quadricep-muscle biopsies. INTERVENTION: Random assignment to a 6-month course of one of four protocols: rhGH administered subcutaneously daily at bedtime, rhGH and a structured resistance exercise program, structured resistance exercise with placebo injections, or placebo injections only. MEASUREMENTS: Muscle biopsy specimens were obtained from the vastus lateralis muscle. Isokinetic dynamometry strength tests were used to monitor individual progress and to adjust the weights used in the exercise program. Serum insulin-like growth factor-I (IGF-I) was measured and body composition was measured using a Hologic QDR 1000W dual X-ray densitometer. RESULTS: The administration of rhGH resulted in significant increase in circulating IGF-I levels in the individuals receiving rhGH treatment. Muscle strength increased significantly in both the rhGH/exercise (+55.6%, P =.0004) as well as the exercise alone (+47.8%, P =.0005) groups. There was a significant increase in the proportion of type 2 fibers between baseline and six months in the combined rhGH treated subjects versus those not receiving rhGH (P =.027). CONCLUSIONS: Our results are encouraging in that they suggest an effect of growth hormone on a specific aging-correlated deficit. IGF-I was increased by administrating rhGH and muscle strength was increased by exercise. The administration of rhGH to frail older individuals in this study resulted in significant changes in the proportions of fiber types. Whether changes in fiber cross-sectional area or absolute number occur with long-term growth hormone administration requires further study.
Asunto(s)
Terapia por Ejercicio/métodos , Anciano Frágil , Hormona del Crecimiento/deficiencia , Hormona del Crecimiento/uso terapéutico , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/fisiología , Debilidad Muscular/rehabilitación , Levantamiento de Peso , Factores de Edad , Anciano , Análisis de Varianza , Biopsia , Composición Corporal , Terapia Combinada , Método Doble Ciego , Femenino , Evaluación Geriátrica , Humanos , Inyecciones Subcutáneas , Factor I del Crecimiento Similar a la Insulina/metabolismo , Masculino , Fibras Musculares Esqueléticas/ultraestructura , Debilidad Muscular/sangre , Debilidad Muscular/diagnóstico , Debilidad Muscular/etiología , Debilidad Muscular/fisiopatología , Resultado del TratamientoRESUMEN
Growth hormone secretagogues (GHSs) represent attractive therapeutic alternatives to recombinant growth hormone (GH), given their ability to amplify pulsatile hormone secretion in a relatively physiologic manner. CP-424,391 (391) is a novel, orally active pyrazolinone-piperidine [corrected] GHS. In rat pituitary cell cultures, 391 stimulated GH release with an EC50 = 3 nM. The addition of 391 to rat pituitary cells activated intracellular calcium signaling but did not elevate intracellular cyclic adenosine monophosphate (cAMP). 391 also modulated the effects of GH-releasing hormone and somatostatin on pituitary cell GH-release and intracellular signaling. In nonpituitary cell lines, the ability of 391 to stimulate intracellular signaling was dependent on the expression of recombinant human GHS receptor. Acute administration of 391 to anesthetized rats or to conscious dogs induced pulsatile release of G H in a dose-dependent manner. Plasma insulin-like growth factor-I (IGF-I) was elevated progressively over a 5-d course of daily oral dosing in dogs. Chronic oral administration of 391 augmented body weight gain in rats and dogs. Thus, the peptidomimetic GHS 391 has potential utility for the treatment of clinical conditions that could benefit from systemic augmentation of GH and IGF-I levels.
Asunto(s)
Hormona del Crecimiento/metabolismo , Péptidos/farmacología , Piperidinas/farmacología , Pirazoles/farmacología , Administración Oral , Hormona Adrenocorticotrópica/metabolismo , Animales , Peso Corporal , Calcio/metabolismo , Células Cultivadas , Perros , Femenino , Hormona del Crecimiento/sangre , Hormona Liberadora de Hormona del Crecimiento/antagonistas & inhibidores , Hormona Liberadora de Hormona del Crecimiento/farmacología , Hidrocortisona/sangre , Hidrocortisona/metabolismo , Modelos Animales , Estructura Molecular , Oligopéptidos/farmacología , Péptidos/administración & dosificación , Péptidos/antagonistas & inhibidores , Piperidinas/administración & dosificación , Adenohipófisis/efectos de los fármacos , Adenohipófisis/metabolismo , Pirazoles/administración & dosificación , Ratas , Ratas Sprague-Dawley , Ratas Wistar , Somatostatina/farmacología , Factores de TiempoRESUMEN
Selective estrogen receptor modulators, like tamoxifen and related compounds, have mixed estrogen agonistic/antagonistic effects. Tamoxifen may confer significant cardiovascular benefits without the estrogen-associated risks of endometrial and breast cancer. Droloxifene, a structural analogue of tamoxifen, has estrogen agonistic effects on bone and antagonistic effects on endometrial and breast tissue. Its cardiovascular effects in women are unknown. We enrolled 24 healthy postmenopausal women in a randomized, double-blind, 2-period crossover trial comparing the effects of droloxifene (60 mg/d) with conjugated estrogen (0.625 mg/d). Plasma lipids, coagulation and fibrinolytic factors, and brachial flow-mediated vasodilator responses were measured at the beginning and end of each treatment period. Droloxifene and estrogen resulted in 16.6% and 12.0% reductions, respectively, in low density lipoprotein cholesterol (P<0.001) and 13.2% and 9.5% reductions, respectively, in lipoprotein(a) (P<0.05). In contrast, estrogen, but not droloxifene, increased high density lipoprotein (18.5%, P<0.001). Droloxifene also reduced fibrinogen by 17.8% versus a 7.3% reduction with estrogen (P=0.004) but produced no estrogen-like changes in plasminogen, plasminogen activator inhibitor-1, or tissue plasminogen activator. Droloxifene and estrogen produced 36.4% and 27.3% increases, respectively, in flow-mediated vasodilation (percent change from baseline, P<0.05 for both). Droloxifene has estrogen agonistic properties regarding low density lipoprotein and lipoprotein(a) metabolism, certain coagulation factors, and endothelium-dependent vasodilation but, unlike estrogen, has no effect on high density lipoprotein/triglyceride metabolism and the fibrinolytic cascade. It remains unknown whether droloxifene can confer a true cardiovascular benefit.
Asunto(s)
Sistema Cardiovascular/efectos de los fármacos , Antagonistas de Estrógenos/farmacología , Estrógenos/agonistas , Posmenopausia , Tamoxifeno/análogos & derivados , Anciano , Antitrombina III/metabolismo , Arteria Braquial/efectos de los fármacos , Arteria Braquial/fisiología , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Estudios Cruzados , Método Doble Ciego , Estrógenos Conjugados (USP)/farmacología , Femenino , Fibrinógeno/metabolismo , Fibrinólisis/efectos de los fármacos , Humanos , Lípidos/sangre , Persona de Mediana Edad , Tamoxifeno/farmacología , Vasodilatación/efectos de los fármacosRESUMEN
BACKGROUND: Animal studies suggest that substance P, a peptide that preferentially activates the neurokinin-1 (NK1) receptor, is involved in pain transmission, with particular importance in pain after inflammation. METHODS: The analgesic efficacy of CP-99,994, a NK1 receptor antagonist, was compared with ibuprofen and placebo in 78 subjects undergoing third molar extraction. The initial 60 subjects randomly received 1 of 3 possible treatments in a double-blind fashion before oral surgery: 750 microg/kg CP-99,994 infused intravenously over 5 hours on a tapering regimen starting 2 hours before surgery, 600 mg oral ibuprofen 30 minutes before surgery, or placebo. In a second study, 18 subjects were randomized to the same regimens starting 30 minutes before surgery to maximize the amount of CP-99,994 circulating during pain onset. RESULTS: In the first study, ibuprofen significantly reduced pain, as measured by visual analog scale, from 90 to 240 minutes postoperatively compared with placebo. CP-99,994 produced analgesia that was significant at 90 minutes (P < 0.01 compared with placebo), but not at subsequent time points. In the second study, ibuprofen and, to a lesser extent, CP-99,994 significantly suppressed pain in comparison to placebo at 60, 90, and 120 minutes (P < 0.05). The incidence of side effects was similar across groups. CONCLUSIONS: This replicate demonstration that a NK1 receptor blocker relieves clinical pain supports the hypothesis that substance P contributes to the generation of pain in humans. The reduction in postoperative pain at doses not producing side effects suggests that NK1 antagonists may be clinically useful.
Asunto(s)
Analgésicos/farmacología , Antagonistas del Receptor de Neuroquinina-1 , Dolor Postoperatorio/tratamiento farmacológico , Piperidinas/farmacología , Extracción Dental/efectos adversos , Enfermedad Aguda , Analgésicos/uso terapéutico , Método Doble Ciego , Humanos , Dimensión del Dolor , Dolor Postoperatorio/metabolismo , Piperidinas/uso terapéutico , Factores de Tiempo , Resultado del TratamientoRESUMEN
OBJECTIVE: The hypothesis that decreased growth hormone (GH) secretion contributes to the functional decline that occurs with aging is far from substantiated. There have been few studies addressing the distribution and correlates of IGF-I, an indicator of GH activity, in nonclinical populations. As part of a growth hormone intervention trial, we examined the cross-sectional relations between IGF-I levels and multiple measures of physical function, body composition, and strength in a group of older men and women exhibiting mild to moderate reductions in measured physical performance. METHODS: Using a variety of advertising techniques, 155 older subjects were recruited from a metropolitan area to participate in a growth hormone and exercise intervention study. At baseline, all subjects had blood drawn for IGF-I and underwent testing of body composition using dual X-ray absorptiometry, muscle strength using isokinetic dynamometry, and functional assessment using timed performance measures and self-report. Associations between levels of IGF-I, body composition, strength, and physical function were assessed after dividing men and women separately into tertiles of IGF-I as well as treating IGF-I as a continuous variable. RESULTS: Men had higher IGF-I levels than women, and a significant inverse correlation was observed between age and IGF-I in men (r=-0.29, P=.009). There were no clear trends for associations between tertiles of IGF-I, and any of the variables tested. Linear regression models with IGF-I treated as a continuous measure were not associated significantly with any of the measures of physical function, body composition, or strength (all P > 0.05). CONCLUSIONS: In conclusion, although IGF-I levels declined with age in men, these data did not demonstrate an association between IGF-I and measures of muscle strength, body composition, or physical functioning. These findings support the growing body of evidence that IGF-I levels may not be an indicator of growth hormone activity in older persons.
Asunto(s)
Composición Corporal/fisiología , Personas con Discapacidad , Factor I del Crecimiento Similar a la Insulina/análisis , Músculos/fisiología , Esfuerzo Físico/fisiología , Anciano , Análisis de Varianza , Distribución de Chi-Cuadrado , Personas con Discapacidad/estadística & datos numéricos , Tolerancia al Ejercicio/fisiología , Femenino , Humanos , Masculino , Análisis de Regresión , Rhode IslandRESUMEN
Stimulation of the cornea activates neurons in two distinct regions of the spinal trigeminal nucleus: at the transition between trigeminal subnucleus interpolaris and subnucleus caudalis and at the transition between trigeminal subnucleus caudalis and the upper cervical spinal cord as estimated by expression of the immediate early gene, c-fos. To determine if receptors for substance P or neurokinin A, neurokinin 1 and neurokinin 2 receptors, respectively, contribute to the production of Fos-positive neurons in these brainstem regions, receptor-selective antagonists were given intracerebroventricularly 15 min prior to stimulation of the cornea in anesthetized rats. The number of Fos-positive neurons produced in superficial laminae at the trigeminal subnucleus caudalis/cervical cord transition by application of the selective small fiber excitant, mustard oil, to the corneal surface was reduced by the neurokinin 1 receptor antagonist, CP99,994 (5-100 nmol, i.c.v.) and the neurokinin 2 receptor antagonist, MEN10,376 (0.01-1.0 nmol, i.c.v.). Combined pretreatment with CP99,994 and the competitive N-methyl-D-aspartate receptor antagonist, CPP, caused a greater reduction in c-fos expression at the subnucleus caudalis/cervical cord transition than after either drug alone suggesting interaction between receptors for glutamate and substance P. Tachykinin receptor antagonists did not reduce the number of Fos-positive neurons produced at the subnucleus interpolaris/subnucleus caudalis transition. The elevation in plasma concentration of adrenocorticotropin, but not the increases in arterial pressure or heart rate, evoked by corneal stimulation was prevented by pretreatment with CP99,994 or MEN10,376 at doses lower than those needed to reduce c-fos expression. The results indicate that receptors for substance P and neurokinin A contribute to the transmission of sensory input from corneal nociceptors to brainstem neurons in trigeminal subnucleus caudalis and to increased activity of the hypothalamo-pituitary axis that accompanies acute stimulation of the cornea.
Asunto(s)
Córnea/fisiología , Antagonistas del Receptor de Neuroquinina-1 , Proteínas Proto-Oncogénicas c-fos/biosíntesis , Receptores de Neuroquinina-2/antagonistas & inhibidores , Núcleo Espinal del Trigémino/metabolismo , Hormona Adrenocorticotrópica/sangre , Animales , Sistema Nervioso Autónomo/efectos de los fármacos , Sistema Nervioso Autónomo/fisiología , Capsaicina/farmacología , Hormonas/sangre , Inmunohistoquímica , Masculino , Neuroquinina A/análogos & derivados , Neuroquinina A/farmacología , Fragmentos de Péptidos/farmacología , Piperidinas/farmacología , Ratas , Ratas Sprague-Dawley , Núcleo Espinal del Trigémino/efectos de los fármacos , Núcleo Espinal del Trigémino/fisiologíaRESUMEN
The percutaneous muscle biopsy technique is used in clinical practice and biomedical research. We developed a new enhanced-suction technique [suction-enhancing nipples (SEN)] and compared it with techniques currently in practice by assessing biopsy yields on anesthetized pigs. We applied the enhanced-suction technique to human subjects participating in a clinical trial. In the pig, there was a mean 91% (1.9-fold) increase in the size of the samples obtained with the 4-mm needle when SEN was used and a mean 507% (fivefold) increase in sample size when the SEN was applied to the 6-mm needles. Nine passes of the 6-mm needle with SEN obtained from five consecutive human subjects yielded a mean individual sample size of 109.4 mg or 219.4 mg per needle pass when using the double-sample technique. Adequate tissue samples for histomorphometric and other analyses were obtained in all samples obtained. The percutaneous muscle biopsy performed with enhanced suction using inexpensive, readily available nipples enhances tissue yield two- to fivefold.
Asunto(s)
Biopsia con Aguja/métodos , Músculos/patología , Succión , Anciano , Animales , Biopsia con Aguja/instrumentación , Diseño de Equipo , Femenino , Humanos , Masculino , Succión/instrumentación , PorcinosRESUMEN
To investigate the role of NK1 receptors in the pathogenesis of bronchoconstriction and cough in asthma, we performed a randomized, double-blind, crossover study on the effects of a selective non-peptide tachykinin NK1 receptor antagonist (CP-99,994) on baseline measures of lung function and on hypertonic saline-induced bronchoconstriction and cough in 14 male subjects with mild asthma. CP-99,994 (250 micrograms/2 hours) and placebo were administered intravenously in 2-h infusions during consecutive visits 5 to 7 d apart. Specific airway resistance (SRaw) was measured and spirometry was performed at baseline and at 35 and 60 min. Next, hypertonic saline challenge was performed by delivering 10 breaths of saline of increasing concentration (0.9 to 7% in 1% increments at 5-min intervals) via an ultrasonic nebulizer until SRaw increased from baseline by 200% or 20 units, whichever was greater. Throughout the challenge cough was counted from a taped record made from two microphones placed close to the subject's larynx. We found that CP-99,994 did not significantly affect SRaw or spirometric measures of lung function during the first hour of infusion. Although CP-99,994 infusion markedly attenuated the bronchoconstrictor response to the saline challenge in two subjects, it did not significantly decrease the area under curves obtained for SRaw and cough during saline challenge for the group as a whole (p = 0.9 for SRaw;p = 0.8 for cough). We conclude that administration of 250 micrograms/kg of CP-99,994 over 2 h does not significantly inhibit hypertonic saline-induced bronchoconstriction or cough in subjects with mild asthma and does not have acute bronchodilator activity in these subjects.
Asunto(s)
Asma/fisiopatología , Broncoconstricción/efectos de los fármacos , Tos/fisiopatología , Piperidinas/farmacología , Estereoisomerismo , Adulto , Resistencia de las Vías Respiratorias/efectos de los fármacos , Estudios Cruzados , Método Doble Ciego , Humanos , Masculino , Persona de Mediana Edad , Pruebas de Función Respiratoria , Solución Salina HipertónicaRESUMEN
To study the efficacy and mechanism of action of the intragastric bubble, 1- to 5-ml silicone bubbles were surgically implanted into the stomachs of 10- to 12-week-old female rats. To test the hypothesis that the satiety effects of the implant are mediated by visceral sensory nerves, a subgroup was treated as neonates with the sensory neurotoxin capsaicin, 50 mg/kg subcutaneously. In control animals, the implants caused a transient decrease in body weight, compared to sham-implanted animals, most evident at three days and abolished by 18 days after operation. In contrast, capsaicin-treated animals did not lose weight in response to gastric implantation. Substance P was decreased in the vagus nerves of capsaicin-treated animals, confirming sensory denervation. At autopsy, all gastric implanted rats had enlarged stomachs. We conclude that intact sensory innervation is essential for weight loss in response to the gastric bubble.
Asunto(s)
Capsaicina/farmacología , Balón Gástrico , Neuronas Aferentes/fisiología , Saciedad/fisiología , Estómago/inervación , Nervio Vago/fisiología , Pérdida de Peso , Animales , Femenino , Degeneración Nerviosa/efectos de los fármacos , Ratas , Ratas Endogámicas , Siliconas , Sustancia P/análisisRESUMEN
An oxonium ion at m/z317 is present in the desorption electron ionization and ammonia desorption chemical ionization mass spectra of peracetylated disaccharides, comprised of glucopyranose units linked (1-->2), (1-->3), (1-->4) and (1-->6), but is absent in the spectra of the (1-->1)-linked isomer. The ion at m/z317, which is derived from the reducing moiety, has an O-formyl group at the position of linkage to the non-reducing moiety, and O-acetyl groups at each of the remaining positions. The isomeric monoformyl, triacetyl oxonium ions (at m/z317), derived from the (1-->2)-, (1-->3)-, (1-->4)- and (1-->6)-linked disaccharides, give distinctly different mass-analysed ion kinetic energy spectra, thereby enabling the linkage position to be assigned unambiguously.
Asunto(s)
Disacáridos/análisis , Glicósidos/análisis , Acetilación , Conformación de Carbohidratos , Electroquímica , Espectrometría de MasasRESUMEN
The expression of two ProTRH derived peptides, thyrotropin--releasing hormone (TRH) and PrePro-TRH25-50 (PYE27) was studied in anterior pituitary (AP) cells cultured in monolayer for up to 21 days. TRH levels in extracted cells rose from undetectable at 3 days to 267 +/- 22.5 fmol/well (p less than 0.01) at 21 days in culture. When AP tissue was extracted without dissociation or culture TRH was undetectable. The molar ratio of TRH/PYE27 was approximately 5:1 as predicted by the structure of PreProTRH. Extracts of cultured AP cells coeluted with TRH and PYE27 standards when subjected to HPLC analysis. Basal TRH secretion was 13.2 +/- 1.8 fmol/well/30 min at 18 days in culture; depolarizing concentrations of K+ (55 mM) caused a 2.2 fold (p less than 0.01) Ca++ dependent increase in TRH release. Immunostaining for PYE27 was found in approximately 10% of the cell population. Our results suggest that authentic ProTRH peptides are synthesized by AP cells in long term culture but not in situ. While the mechanism of activation of the PreProTRH gene needs to be elucidated we propose that TRH and/or other ProTRH derived peptides may exert paracrine effects on AP function.
Asunto(s)
Adenohipófisis/metabolismo , Precursores de Proteínas/biosíntesis , Hormona Liberadora de Tirotropina/biosíntesis , Animales , Animales Recién Nacidos , Células Cultivadas , Cromatografía Líquida de Alta Presión , Técnicas para Inmunoenzimas , Masculino , Precursores de Proteínas/metabolismo , Ratas , Ratas Endogámicas , Hormona Liberadora de Tirotropina/metabolismo , Factores de TiempoAsunto(s)
Factores de Crecimiento Nervioso/farmacología , Neuronas Aferentes/fisiología , Precursores de Proteínas/genética , ARN Mensajero/genética , Taquicininas/genética , Nervio Vago/fisiología , Animales , Animales Recién Nacidos , Northern Blotting , Células Cultivadas , Neuronas Aferentes/citología , Neuronas Aferentes/efectos de los fármacos , Hibridación de Ácido Nucleico , ARN Mensajero/análisis , ARN Mensajero/efectos de los fármacos , RatasRESUMEN
Under conditions of desorption-chemical ionization or fast-atom-bombardment mass-spectrometry, the azido groups in some carbohydrate derivatives and other substances undergo apparent reduction to amino groups. Experimental evidence is provided to corroborate the reduction, and possible explanations are proposed for the phenomenon.
Asunto(s)
Azidas/química , Glicósidos/química , Amoníaco/análisis , Conformación de Carbohidratos , Secuencia de Carbohidratos , Datos de Secuencia Molecular , Espectrometría de Masa Bombardeada por Átomos Veloces/métodosRESUMEN
Substance P, the widely distributed 11 amino acid neuropeptide, is present in up to 20% of vagal sensory cell bodies and the fibers emanating from them. To study the factors regulating the release of SP, vagal sensory (nodose or nodose/jugular) ganglia were obtained from neonatal rats and dissociated using neutral protease. Survival of plated neurons on collagen substrate was 10-20% at 2 weeks and 20-30% when neurons were plated over previously dissociated rat atriacytes. Substance P content was low in cultures for the first several days, then rose linearly to 0.1-0.2 pg/surviving neuron. Substance P was released into a 4.5 mM potassium medium at a steady rate of 0.036%/min. In 50 mM K+ supplemented medium, total release during 20 min increased 5-8-fold and steady-state release increased 4-5-fold to 0.15%/min. The sensory neuron specific excitatory neurotoxin, capsaicin, evoked SP release in similar amounts to 50 mM K+. Both net K(+)- and capsaicin-evoked, but not basal release were completely inhibited by 3.5 mM cobalt chloride. Bradykinin, 1-100 nM, stimulated SP release 2-4 times above basal levels. Forskolin and phorbol ester also increased SP release 1.5-3 times basal amounts. In summary, substance P is present in cultured vagal sensory neurons in amounts similar to in vivo and is released in response to sensory specific stimuli. These cultures should allow exploration of some of the tissue specific factors regulating neurotransmitter release in the sensory vagus nerve.
Asunto(s)
Neuronas Aferentes/metabolismo , Sustancia P/metabolismo , Nervio Vago/metabolismo , Animales , Animales Recién Nacidos , Bradiquinina/farmacología , Capsaicina/farmacología , Cromatografía Líquida de Alta Presión , Cinética , Neuronas Aferentes/efectos de los fármacos , Ganglio Nudoso/efectos de los fármacos , Ganglio Nudoso/metabolismo , Forbol 12,13-Dibutirato/farmacología , Potasio/farmacología , Ratas , Ratas Endogámicas , Sustancia P/aislamiento & purificación , Nervio Vago/efectos de los fármacosRESUMEN
The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can result from diverse conditions. There have been only two published reports linking this syndrome with herpes zoster infections--one disseminated and the other confined to the chest wall. We have reported a case in which herpes zoster infection of the chest wall probably precipitated the development of this syndrome.
Asunto(s)
Herpes Zóster/complicaciones , Síndrome de Secreción Inadecuada de ADH/etiología , Enfermedades Cutáneas Infecciosas/complicaciones , Anciano , Femenino , Humanos , Hiponatremia/etiología , TóraxRESUMEN
In order to evaluate the effectiveness of a gastric implant in an animal model of dietary obesity, silicone implants (2.5 ml) were inserted into the stomachs of male rats maintained on a chow or "cafeteria" diet. At the time of implantation, the cafeteria fed rats weighed 14% more than chow fed controls. Overweight cafeteria fed animals lost weight in response to the gastric implant, whereas control chow fed animals did not. Both implant groups had significant increases in stomach weights in contrast to sham implant groups, but the increase was much less in the cafeteria diet group. The fasting plasma levels of the gastrointestinal hormones, gastrin and pancreatic polypeptide, and oxytocin (a marker of vagal afferent function) were measured by radioimmunoassay. Cafeteria fed sham or implanted animals had significantly higher fasting levels of plasma oxytocin and gastrin, and significantly lower plasma levels of pancreatic polypeptide than the chow fed groups. These studies demonstrate that the gastric implant has more effect on weight in overweight animals on a palatable mixed diet, perhaps related to both mechanical and neural factors.
Asunto(s)
Dieta , Gastrinas/sangre , Obesidad/terapia , Oxitocina/sangre , Polipéptido Pancreático/sangre , Prótesis e Implantes , Animales , Peso Corporal , Masculino , Obesidad/sangre , Obesidad/patología , Tamaño de los Órganos , Ratas , Ratas Endogámicas , Estómago/patologíaRESUMEN
Nodose (inferior vagal sensory) ganglia were removed from neonatal rats, enzymatically dispersed using neutral protease, and maintained on previously dispersed rat atriacytes. After 7-10 days in culture, calcitonin gene-related peptide (CGRP) was present in 1-3 times the molar amount of substance P (SP). The content of SP was doubled by the addition of nerve growth factor (NGF) whereas CGRP was significantly less increased by 50% or less. The addition of forskolin increased SP and CGRP levels in cultures with or without NGF by 60-80 percent. Phorbol ester (PMA) did not alter SP content but significantly raised CGRP content by 40% in NGF supplemented cultures (P less than 0.001). Corticosterone, 0.01-0.1 microM, reduced SP content by 30% independently of NGF but had no effect on CGRP. These studies demonstrate that SP in vagal sensory neurons is more sensitive than CGRP to the effects of NGF or corticosterone. Both peptides are up-regulated by presumed increases in intracellular cyclic AMP, while CGRP (or CGRP neurons) may be independently regulated by protein kinase C.
Asunto(s)
Corticosterona/farmacología , Factores de Crecimiento Nervioso/farmacología , Neuronas Aferentes/metabolismo , Neuropéptidos/metabolismo , Ganglio Nudoso/citología , Sustancia P/metabolismo , Nervio Vago/citología , Animales , Péptido Relacionado con Gen de Calcitonina , Recuento de Células , Células Cultivadas , Colforsina/farmacología , Neuronas Aferentes/efectos de los fármacos , Ganglio Nudoso/efectos de los fármacos , Ganglio Nudoso/metabolismo , Ésteres del Forbol/farmacología , Ratas , Ratas EndogámicasRESUMEN
Over the past twenty years, each of the five major hypothalamic releasing or release-inhibiting hormones has been sequenced and its gene structure determined. With the use of molecular biological techniques, such as in situ hybridization, Northern blot analysis or gene constructs for in vitro or in vivo transfection studies--together with 'traditional' neuroendocrinological techniques, such as immunocytochemistry, radio-immunoassay and portal vessel cannulation--investigators have been able to address major issues in neuroendocrine regulation. Several common themes have emerged: messenger RNA expression is uniformly present in neurons that are immunopositive for the specific hypothalamic hormone. Steady state RNA levels within the hypophysiotropic neuron groups are either increased or reduced by changes in specific target hormones that conform to predictions based on previous physiological data. Regulation by the requisite peripheral hormone is exquisitely anatomically specific and is not evident in extrahypophysiotropic regions. Determining the receptor or genetic basis of this specificity is a major focus of current research. Clarifying the apparently lesser role of afferent neural pathways to the hypothalamus in regulating releasing hormone mRNA levels is also an important challenge. Clinically, the measurement of levels of releasing hormones in the peripheral circulation appears to be of limited usefulness, except in rare cases of ectopic GRH or CRH secretion. For diagnostic purposes, each of the releasing hormones has specific utility in amplifying the release and measurement of pituitary hormones, both to clarify the overall physiological activity of the hypothalamic-pituitary-target hormone axis and to further define the anatomic locus of any underlying disturbance. The usefulness of somatostatin as a diagnostic tool is presently limited, but the development of SS receptor antagonists might have significant impact in future clinical investigation. The molecular mechanisms of action of the hypothalamic hormones have been separated into those whose receptor-effector function is mediated by the cAMP-adenylate cyclase pathway(s), GRH and CRH, and those working through the phosphoinositide-protein kinase C cascade, GnRH and TRH. Each of the hormone receptors is coupled to intermediary G proteins, somatostatin uniquely to the inhibitory subclass. The mechanisms responsible for sensitization (priming) or desensitization are not fully understood but are presumably related to receptor down regulation and protein phosphorylation.(ABSTRACT TRUNCATED AT 400 WORDS)