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4.
Front Endocrinol (Lausanne) ; 12: 727915, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34526970

RESUMEN

In obesity and type 2 diabetes, numerous genes are differentially expressed, and microRNAs are involved in transcriptional regulation of target mRNAs, but miRNAs critically involved in the appetite control are not known. Here, we identified upregulation of miR-342-3p and its host gene Evl in brain and adipose tissues in C57BL/6 mice fed with high fat-high sucrose (HFHS) chow by RNA sequencing. Mir342 (-/-) mice fed with HFHS chow were protected from obesity and diabetes. The hypothalamic arcuate nucleus neurons co-express Mir342 and EVL. The percentage of activated NPY+pSTAT3+ neurons were reduced, while POMC+pSTAT3+ neurons increased in Mir342 (-/-) mice, and they demonstrated the reduction of food intake and amelioration of metabolic phenotypes. Snap25 was identified as a major target gene of miR-342-3p and the reduced expression of Snap25 may link to functional impairment hypothalamic neurons and excess of food intake. The inhibition of miR-342-3p may be a potential candidate for miRNA-based therapy.


Asunto(s)
Regulación del Apetito/genética , MicroARNs/genética , Obesidad , Células 3T3-L1 , Animales , Núcleo Arqueado del Hipotálamo/metabolismo , Núcleo Arqueado del Hipotálamo/fisiología , Células Cultivadas , Dieta Alta en Grasa , Regulación de la Expresión Génica , Humanos , Hipotálamo/metabolismo , Hipotálamo/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Obesos , MicroARNs/metabolismo , Neuronas/metabolismo , Neuronas/fisiología , Obesidad/etiología , Obesidad/genética , Obesidad/metabolismo , Regulación hacia Arriba/genética
5.
Biochem Biophys Res Commun ; 557: 199-205, 2021 06 11.
Artículo en Inglés | MEDLINE | ID: mdl-33872989

RESUMEN

Malignant peripheral nerve sheath tumor (MPNST), a highly malignant tumor that arises in peripheral nerve tissues, is known to be highly resistant to radiation and chemotherapy. Although there are several reports on genetic mutations and epigenetic changes that define the pathogenesis of MPNST, there is insufficient information regarding the microenvironment that contributes to the malignancy of MPNST. In the present study, we demonstrate that adrenaline increases the cancer stem cell population in MPNST. This effect is mediated by adrenaline stimulation of beta-2 adrenergic receptor (ADRB2), which activates the Hippo transducer, YAP/TAZ. Inhibition and RNAi experiments revealed that inhibition of ADRB2 attenuated the adrenaline-triggered activity of YAP/TAZ and subsequently attenuated MPNST cells stemness. Furthermore, ADRB2-YAP/TAZ axis was confirmed in the MPNST patients' specimens. The prognosis of patients with high levels of ADRB2 was found to be significantly worse. These data show that adrenaline exacerbates MPNST prognosis and may aid the development of new treatment strategies for MPNST.


Asunto(s)
Epinefrina/farmacología , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Neoplasias de la Vaina del Nervio/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Transducción de Señal/efectos de los fármacos , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Línea Celular Tumoral , Humanos , Neoplasias de la Vaina del Nervio/genética , Neoplasias de la Vaina del Nervio/patología , Pronóstico , Interferencia de ARN , Receptores Adrenérgicos beta 2/genética , Transducción de Señal/genética , Factores de Transcripción/metabolismo , Proteínas Señalizadoras YAP
6.
Acta Neuropathol Commun ; 9(1): 29, 2021 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-33618763

RESUMEN

Glioblastoma (GBM) is the most lethal primary brain tumor characterized by significant cellular heterogeneity, namely tumor cells, including GBM stem-like cells (GSCs) and differentiated GBM cells (DGCs), and non-tumor cells such as endothelial cells, vascular pericytes, macrophages, and other types of immune cells. GSCs are essential to drive tumor progression, whereas the biological roles of DGCs are largely unknown. In this study, we focused on the roles of DGCs in the tumor microenvironment. To this end, we extracted DGC-specific signature genes from transcriptomic profiles of matched pairs of in vitro GSC and DGC models. By evaluating the DGC signature using single cell data, we confirmed the presence of cell subpopulations emulated by in vitro culture models within a primary tumor. The DGC signature was correlated with the mesenchymal subtype and a poor prognosis in large GBM cohorts such as The Cancer Genome Atlas and Ivy Glioblastoma Atlas Project. In silico signaling pathway analysis suggested a role of DGCs in macrophage infiltration. Consistent with in silico findings, in vitro DGC models promoted macrophage migration. In vivo, coimplantation of DGCs and GSCs reduced the survival of tumor xenograft-bearing mice and increased macrophage infiltration into tumor tissue compared with transplantation of GSCs alone. DGCs exhibited a significant increase in YAP/TAZ/TEAD activity compared with GSCs. CCN1, a transcriptional target of YAP/TAZ, was selected from the DGC signature as a candidate secreted protein involved in macrophage recruitment. In fact, CCN1 was secreted abundantly from DGCs, but not GSCs. DGCs promoted macrophage migration in vitro and macrophage infiltration into tumor tissue in vivo through secretion of CCN1. Collectively, these results demonstrate that DGCs contribute to GSC-dependent tumor progression by shaping a mesenchymal microenvironment via CCN1-mediated macrophage infiltration. This study provides new insight into the complex GBM microenvironment consisting of heterogeneous cells.


Asunto(s)
Neoplasias Encefálicas/patología , Diferenciación Celular , Proteína 61 Rica en Cisteína/metabolismo , Progresión de la Enfermedad , Glioblastoma/patología , Macrófagos/metabolismo , Microambiente Tumoral , Animales , Línea Celular Tumoral , Femenino , Humanos , Macrófagos/inmunología , Ratones , Análisis de Secuencia de ARN
7.
Clin Auton Res ; 31(2): 165-178, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-32926324

RESUMEN

PURPOSE: The autonomic nervous system, consisting of sympathetic and parasympathetic/vagal nerves, is known to control the functions of any organ, maintaining whole-body homeostasis under physiological conditions. Recently, there has been increasing evidence linking sympathetic and parasympathetic/vagal nerves to cancers. The present review aimed to summarize recent developments from studies addressing the relationship between sympathetic and parasympathetic/vagal nerves and cancer behavior. METHODS: Literature review. RESULTS: Human and animal studies have revealed that sympathetic and parasympathetic/vagal nerves innervate the cancer microenvironment and alter cancer behavior. The sympathetic nerves have cancer-promoting effects on prostate cancer, breast cancer, and melanoma. On the other hand, while the parasympathetic/vagal nerves have cancer-promoting effects on prostate, gastric, and colorectal cancers, they have cancer-suppressing effects on breast and pancreatic cancers. These neural effects may be mediated by ß-adrenergic or muscarinic receptors and can be explained by changes in cancer cell behavior, angiogenesis, tumor-associated macrophages, and adaptive antitumor immunity. CONCLUSIONS: Sympathetic nerves innervating the tumor microenvironment promote cancer progression and are related to stress-induced cancer behavior. The parasympathetic/vagal nerves have variable (promoting or suppressing) effects on different cancer types. Approaches directed toward the sympathetic and parasympathetic/vagal nerves can be developed as a new cancer therapy. In addition to existing pharmacological, surgical, and electrical approaches, a recently developed virus vector-based genetic local neuroengineering technology is a powerful approach that selectively manipulates specific types of nerve fibers innervating the cancer microenvironment and leads to the suppression of cancer progression. This technology will enable the creation of "cancer neural therapy" individually tailored to different cancer types.


Asunto(s)
Neoplasias , Sistema Nervioso Parasimpático , Animales , Sistema Nervioso Autónomo , Humanos , Masculino , Neoplasias/terapia , Sistema Nervioso Simpático , Microambiente Tumoral , Nervio Vago
8.
Parasite Immunol ; 43(5): e12804, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33124059

RESUMEN

Ticks are blood-feeding ectoparasites that transmit a variety of pathogens to host animals and humans, causing severe infectious diseases such as Lyme disease. In a certain combination of animal and tick species, tick infestation elicits acquired immunity against ticks in the host, which can reduce the ability of ticks to feed on blood and to transmit pathogens in the following tick infestations. Therefore, our understanding of the cellular and molecular mechanisms of acquired tick resistance (ATR) can advance the development of anti-tick vaccines to prevent tick infestation and tick-borne diseases. Basophils are a minor population of white blood cells circulating in the bloodstream and are rarely observed in peripheral tissues under steady-state conditions. Basophils have been reported to accumulate at tick-feeding sites during re-infestation in cattle, rabbits, guinea pigs and mice. Selective ablation of basophils resulted in a loss of ATR in guinea pigs and mice, illuminating the essential role of basophils in the manifestation of ATR. In this review, we discuss the recent advance in the elucidation of the cellular and molecular mechanisms underlying basophil recruitment to the tick-feeding site and basophil-mediated ATR.


Asunto(s)
Basófilos/fisiología , Infestaciones por Garrapatas/inmunología , Garrapatas/inmunología , Inmunidad Adaptativa , Animales , Bovinos , Cabras , Cobayas , Histamina/inmunología , Histamina/metabolismo , Humanos , Inmunoglobulina E/metabolismo , Recuento de Leucocitos , Ratones , Conejos , Infestaciones por Garrapatas/prevención & control
9.
Cells ; 9(10)2020 09 23.
Artículo en Inglés | MEDLINE | ID: mdl-32977522

RESUMEN

Boron neutron capture therapy (BNCT) requires pharmaceutical innovations and molecular-based evidence of effectiveness to become a standard cancer therapeutic in the future. Recently, in Japan, 4-borono-L-phenylalanine (BPA) was approved as a boron agent for BNCT against head and neck (H&N) cancers. H&N cancer appears to be a suitable target for BPA-BNCT, because the expression levels of L-type amino acid transporter 1 (LAT1), one of the amino acid transporters responsible for BPA uptake, are elevated in most cases of H&N cancer. However, in other types of cancer including malignant brain tumors, LAT1 is not always highly expressed. To expand the possibility of BNCT for these cases, we previously developed poly-arginine peptide (polyR)-conjugated mercaptoundecahydrododecaborate (BSH). PolyR confers the cell membrane permeability and tumor selectivity of BSH. However, the molecular determinants for the properties are not fully understood. In this present study, we have identified the cluster of differentiation 44 (CD44) protein and translational machinery proteins as a major cell surface target and intracellular targets of BSH-polyR, respectively. CD44, also known as a stem cell-associated maker in various types of cancer, is required for the cellular uptake of polyR-conjugated molecules. We showed that BSH-polyR was predominantly delivered to a CD44High cell population of cancer cells. Once delivered, BSH-polyR interacted with the translational machinery components, including the initiation factors, termination factors, and poly(A)-biding protein (PABP). As a proof of principle, we performed BSH-polyR-based BNCT against glioma stem-like cells and revealed that BSH-polyR successfully induced BNCT-dependent cell death specifically in CD44High cells. Bioinformatics analysis indicated that BSH-polyR would be suitable for certain types of malignant tumors. Our results shed light on the biochemical properties of BSH-polyR, which may further contribute to the therapeutic optimization of BSH-BNCT in the future.


Asunto(s)
Borohidruros/farmacología , Terapia por Captura de Neutrón de Boro , Neoplasias Encefálicas/tratamiento farmacológico , Fenilalanina/farmacología , Compuestos de Sulfhidrilo/farmacología , Terapia por Captura de Neutrón de Boro/métodos , Humanos , Péptidos/metabolismo , Péptidos/farmacología , Fenilalanina/metabolismo , Sodio/metabolismo , Sodio/farmacología
10.
NMC Case Rep J ; 7(2): 47-52, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32322450

RESUMEN

Intracranial mesenchymal chondrosarcoma (MCS) is a rare neoplasm. The diagnosis of MCS is confirmed by the presence of a biphasic pattern on histological examination, comprising undifferentiated small round cells admixed with islands of well-differentiated hyaline cartilage; however, a differential diagnosis may be challenging in some cases. A 28-year-old woman with a 2-month history of headache was referred to our hospital. Radiologic studies showed an extra-axial lobulated mass composed of calcified and uncalcified areas occupying the left middle fossa. Surgical resection was planned, but her headache suddenly worsened before her planned hospital admission and she was admitted as an emergency. Radiologic studies showed an acute hemorrhage in the uncalcified part of the mass. The mass was resected via the left zygomatic approach after embolization of the feeder vessels. The most likely histopathological diagnosis was MCS. However, the typical bimorphic pattern was not identified in our surgical samples; each undifferentiated area and well-differentiated area was observed separately in different tissue specimens, and no islands of well-differentiated hyaline cartilage were identified within the undifferentiated areas in the same specimen. Molecular assays confirmed the presence of HEY1-NCOA2 fusion. IRF2BP2-CDX1 fusion and IDH1/2 mutations were negative. The final diagnosis of MCS was made based on the presence of HEY1-NCOA2 gene fusion. MCS should be included in the differential diagnosis when radiologic studies show an extra-axial lobulated mass with calcification. Furthermore, molecular demonstration of HEY1-NCOA2 gene fusion may help make a precise diagnosis of MCS, especially in surgical samples lacking the typical histopathological features.

11.
Nat Neurosci ; 22(8): 1289-1305, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31285612

RESUMEN

The effects of autonomic innervation of tumors on tumor growth remain unclear. Here we developed a series of genetic techniques to manipulate autonomic innervation in a tumor- and fiber-type-specific manner in mice with human breast cancer xenografts and in rats with chemically induced breast tumors. Breast cancer growth and progression were accelerated following stimulation of sympathetic nerves in tumors, but were reduced following stimulation of parasympathetic nerves. Tumor-specific sympathetic denervation suppressed tumor growth and downregulated the expression of immune checkpoint molecules (programed death-1 (PD-1), programed death ligand-1 (PD-L1), and FOXP3) to a greater extent than with pharmacological α- or ß-adrenergic receptor blockers. Genetically induced simulation of parasympathetic innervation of tumors decreased PD-1 and PD-L1 expression. In humans, a retrospective analysis of breast cancer specimens from 29 patients revealed that increased sympathetic and decreased parasympathetic nerve density in tumors were associated with poor clinical outcomes and correlated with higher expression of immune checkpoint molecules. These findings suggest that autonomic innervation of tumors regulates breast cancer progression.


Asunto(s)
Fibras Autónomas Preganglionares/patología , Neoplasias de la Mama/patología , Antagonistas Adrenérgicos/farmacología , Animales , Antígeno B7-H1/genética , Desnervación , Progresión de la Enfermedad , Femenino , Factores de Transcripción Forkhead/genética , Xenoinjertos , Humanos , Ratones , Ratones Endogámicos BALB C , Trasplante de Neoplasias , Sistema Nervioso Parasimpático/patología , Receptor de Muerte Celular Programada 1/genética , Ratas , Estudios Retrospectivos , Estrés Psicológico/psicología , Sistema Nervioso Simpático/patología
12.
Ultrasound Med Biol ; 45(6): 1455-1465, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30857759

RESUMEN

Arginine-glycine-aspartate (RGD)-carrying microbubbles (MBs) have been utilized as a specific contrast agent for glycoprotein IIb/IIIa (αIIbß3 integrin)-expressing activated platelets in ultrasound molecular imaging. Recently, we found that surface modification with lactadherin provides the RGD motif on the surface of phosphatidylserine-containing clinically available MBs, Sonazoid. Here, we examined the potential of lactadherin-bearing Sonazoid MBs to be targeted MBs for glycoprotein IIb/IIIa using the custom-designed in vitro settings with recombinant αIIbß3 integrin, activated platelets or erythrocyte-rich human clots. By modification of the surface with lactadherin, a large number of Sonazoid MBs were attached to the αIIbß3 integrin-coated and platelet-immobilized plate. Additionally, the video intensity of clots after incubation with lactadherin-bearing Sonazoid MBs was significantly higher than that with unmodified Sonazoid MBs, implying the number of attached Sonazoid MBs was increased by the modification with lactadherin. Our results suggest that the lactadherin-bearing Sonazoid MBs have the potential to be thrombus-targeted MBs.


Asunto(s)
Antígenos de Superficie/farmacología , Medios de Contraste/farmacocinética , Compuestos Férricos/farmacocinética , Aumento de la Imagen/métodos , Hierro/farmacocinética , Microburbujas , Proteínas de la Leche/farmacología , Óxidos/farmacocinética , Ultrasonografía/métodos , Femenino , Humanos , Masculino , Imagen Molecular/métodos , Valores de Referencia
13.
Ultrasound Med Biol ; 44(5): 1063-1073, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29501282

RESUMEN

The usefulness of ultrasound molecular imaging with αvß3 integrin-targeted microbubbles for detecting tumor angiogenesis has been demonstrated. Recently, we developed αvß3 integrin-targeted microbubbles by modifying clinically available microbubbles (Sonazoid, Daiichi-Sankyo Pharmaceuticals, Tokyo, Japan) with a secreted glycoprotein (lactadherin). The aims of our present study were to simplify the preparation of lactadherin-bearing Sonazoid and to examine the diagnostic utility of lactadherin-bearing Sonazoid for αvß3 integrin-expressing tumor vessels by using SK-OV-3-tumor-bearing mice. By incubating 1.2 × 107 Sonazoid microbubbles with 1.0 µg lactadherin, the complicated washing and centrifugation steps during the microbubble preparation could be omitted with no significant reduction in labeling ratio of lactadherin-bearing Sonazoid. In addition, the number of Sonazoid microbubbles accumulated in the SK-OV-3 tumor was significantly increased by modifying Sonazoid with lactadherin. Our data suggest that the lactadherin-bearing Sonazoid is an easily prepared and potentially clinically translatable targeted microbubble for αvß3 integrin-expressing vessels.


Asunto(s)
Medios de Contraste , Aumento de la Imagen/métodos , Integrina alfaVbeta3 , Microburbujas , Neoplasias Ováricas/diagnóstico por imagen , Ultrasonografía/métodos , Animales , Línea Celular Tumoral , Modelos Animales de Enfermedad , Femenino , Compuestos Férricos , Hierro , Ratones , Ratones Endogámicos BALB C , Óxidos , Reproducibilidad de los Resultados
14.
J Physiol Sci ; 68(2): 103-111, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29270856

RESUMEN

The recent development of computer technology has made it possible to simulate the hemodynamics of congenital heart diseases on a desktop computer. However, multi-scale modeling of the cardiovascular system based on computed tomographic and magnetic resonance images still requires long simulation times. The lumped parameter model is potentially beneficial for real-time bedside simulation of congenital heart diseases. In this review, we introduce the basics of the lumped parameter model (time-varying elastance chamber model combined with modified Windkessel vasculature model) and illustrate its usage in hemodynamic simulation of congenital heart diseases using examples such as hypoplastic left heart syndrome and Fontan circulation. We also discuss the advantages of the lumped parameter model and the problems for clinical use.


Asunto(s)
Cardiopatías Congénitas/fisiopatología , Hemodinámica/fisiología , Animales , Simulación por Computador , Ventrículos Cardíacos/fisiopatología , Corazón Auxiliar , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/fisiopatología , Modelos Cardiovasculares
15.
Am J Physiol Regul Integr Comp Physiol ; 314(3): R459-R467, 2018 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-29118022

RESUMEN

Although electrical activation of the carotid sinus baroreflex (baroreflex activation therapy) is being explored as a device therapy for resistant hypertension, possible effects on baroreflex dynamic characteristics of interaction between electrical stimulation and pressure inputs are not fully elucidated. To examine whether the electrical stimulation of the baroreceptor afferent nerve impedes normal short-term arterial pressure (AP) regulation mediated by the stimulated nerve, we electrically stimulated the right aortic depressor nerve (ADN) while estimating the baroreflex dynamic characteristics by imposing pressure inputs to the isolated baroreceptor region of the right ADN in nine anesthetized rats. A Gaussian white noise signal with a mean of 120 mmHg and standard deviation of 20 mmHg was used for the pressure perturbation. A tonic ADN stimulation (2 or 5 Hz, 10 V, 0.1-ms pulse width) decreased mean sympathetic nerve activity (367.0 ± 70.9 vs. 247.3 ± 47.2 arbitrary units, P < 0.01) and mean AP (98.4 ± 7.8 vs. 89.2 ± 4.5 mmHg, P < 0.01) during dynamic pressure perturbation. The ADN stimulation did not affect the slope of dynamic gain in the neural arc transfer function from pressure perturbation to sympathetic nerve activity (16.9 ± 1.0 vs. 14.7 ± 1.6 dB/decade, not significant). These results indicate that electrical stimulation of the baroreceptor afferent nerve does not significantly impede the dynamic characteristics of the arterial baroreflex concomitantly mediated by the stimulated nerve. Short-term AP regulation by the arterial baroreflex may be preserved during the baroreflex activation therapy.


Asunto(s)
Aorta/inervación , Presión Arterial , Barorreflejo , Seno Carotídeo/inervación , Terapia por Estimulación Eléctrica/métodos , Corazón/inervación , Presorreceptores/fisiología , Sistema Nervioso Simpático/fisiología , Animales , Masculino , Mecanotransducción Celular , Ratas Endogámicas WKY , Factores de Tiempo
16.
J Appl Physiol (1985) ; 123(4): 914-921, 2017 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-28751370

RESUMEN

Although the pulsatility of an input pressure is an important factor that determines the arterial baroreflex responses, whether the difference in the input waveforms can meaningfully affect the baroreflex function remains unknown. This study aimed to compare baroreflex responses between two distinct pressure waveforms: a forward saw wave (FSW) and a backward saw wave (BSW). In seven anesthetized rats, carotid sinus pressure was exposed to the FSW or the BSW with a mean of 120 mmHg, pulse pressure of 40 mmHg, and pulse frequency of 1 Hz. Changes in efferent sympathetic nerve activity (SNA) and arterial pressure (AP) during six consecutive saw wave trials (FSW1, BSW1, FSW2, BSW2, FSW3, and BSW3) were examined. The steady-state SNA value during FSW1 was 91.1 ± 1.9%, which was unchanged during FSW2 and FSW3 but significantly increased during BSW1 (106.6 ± 3.4%, P < 0.01), BSW2 (110.6 ± 2.5%, P < 0.01), and BSW3 (111.6 ± 2.3%, P < 0.01). The steady-state AP value during FSW1 was 98.2 ± 8.1 mmHg, which was unchanged during FSW2 and FSW3 but significantly increased during BSW1 (106.7 ± 7.4 mmHg, P < 0.01), BSW2 (105.6 ± 7.8 mmHg, P < 0.01), and BSW3 (103.8 ± 7.2 mmHg, P < 0.05). In conclusion, the FSW was more effective than the BSW in reducing mean SNA and AP. The finding could be applied to designing an artificial pulsatile pressure such as that generated by left ventricular assist devices.NEW & NOTEWORTHY This study examined whether the waveforms of an input pressure alone can affect the baroreflex function by using a forward saw wave and a backward saw wave with the same mean pressure, pulse pressure, and pulse frequency. The forward saw wave was more effective than the backward saw wave in reducing sympathetic nerve activity and arterial pressure. The finding could be applied to designing an artificial pulsatile pressure such as that generated by left ventricular assist devices.


Asunto(s)
Presión Arterial/fisiología , Barorreflejo/fisiología , Presión Sanguínea/fisiología , Seno Carotídeo/fisiología , Animales , Masculino , Ratas , Ratas Endogámicas WKY , Sistema Nervioso Simpático/fisiología
18.
Auton Neurosci ; 205: 21-25, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28242182

RESUMEN

Desipramine (DMI) is a blocker of neuronal norepinephrine (NE) uptake transporter. Although intravenous DMI has been shown to cause centrally-mediated sympathoinhibition and peripheral NE accumulation, its parasympathetic effect remains to be elucidated. We hypothesized that intravenous DMI activates the cardiac vagal nerve via an α2-adrenergic mechanism. Using a cardiac microdialysis technique, changes in myocardial interstitial acetylcholine (ACh) levels in the left ventricular free wall in response to intravenous DMI (1mg·kg-1) were examined in anesthetized rats. In rats with intact vagi (n=7), intravenous DMI increased ACh from 1.67±0.43 to 2.48±0.66nM (P<0.01). In rats with vagotomy (n=5), DMI did not significantly change ACh (from 0.92±0.16 to 0.85±0.23nM). In rats with intact vagi pretreated with intravenous yohimbine (2mg·kg-1), DMI did not significantly change ACh (from 1.25±0.23 to 1.13±0.15nM). In conclusion, while DMI is generally considered to be an agent that predominantly affects sympathetic neurotransmission, it can activate the cardiac vagal nerve via α2-adrenergic stimulation in experimental settings in vivo.


Asunto(s)
Agonistas alfa-Adrenérgicos/farmacología , Fármacos Cardiovasculares/farmacología , Desipramina/farmacología , Parasimpaticomiméticos/farmacología , Acetilcolina/metabolismo , Administración Intravenosa , Inhibidores de Captación Adrenérgica/farmacología , Antagonistas de Receptores Adrenérgicos alfa 2/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Corazón/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Masculino , Miocardio/metabolismo , Ratas Endogámicas WKY , Receptores Adrenérgicos alfa/metabolismo , Vagotomía , Nervio Vago/efectos de los fármacos , Nervio Vago/metabolismo , Yohimbina/farmacología
19.
Am J Physiol Regul Integr Comp Physiol ; 312(5): R787-R796, 2017 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-28274940

RESUMEN

Recent clinical trials in patients with drug-resistant hypertension indicate that electrical activation of the carotid sinus baroreflex can reduce arterial pressure (AP) for more than a year. To examine whether the electrical stimulation from one baroreflex system impedes normal short-term AP regulation via another unstimulated baroreflex system, we electrically stimulated the left aortic depressor nerve (ADN) while estimating the dynamic characteristics of the carotid sinus baroreflex in anesthetized normotensive Wistar-Kyoto (WKY; n = 8) rats and spontaneously hypertensive rats (SHR; n = 7). Isolated carotid sinus regions were perturbed for 20 min using a Gaussian white noise signal with a mean of 120 mmHg for WKY and 160 mmHg for SHR. Tonic ADN stimulation (2 Hz, 10 V, and 0.1-ms pulse width) decreased mean sympathetic nerve activity (73.4 ± 14.0 vs. 51.6 ± 11.3 arbitrary units in WKY, P = 0.012; and 248.7 ± 33.9 vs. 181.1 ± 16.6 arbitrary units in SHR, P = 0.018) and mean AP (90.8 ± 6.6 vs. 81.2 ± 5.4 mmHg in WKY, P = 0.004; and 128.6 ± 9.8 vs. 114.7 ± 10.3 mmHg in SHR, P = 0.009). The slope of dynamic gain in the neural arc transfer function from carotid sinus pressure to sympathetic nerve activity was not different between trials with and without the ADN stimulation (12.55 ± 0.93 vs. 13.03 ± 1.28 dB/decade in WKY, P = 0.542; and 17.37 ± 1.01 vs. 17.47 ± 1.64 dB/decade in SHR, P = 0.946). These results indicate that the tonic ADN stimulation does not significantly modify the dynamic characteristics of the carotid sinus baroreflex.


Asunto(s)
Aorta/fisiopatología , Barorreflejo , Presión Sanguínea , Seno Carotídeo/fisiopatología , Hipertensión/fisiopatología , Nervio Vago/fisiopatología , Animales , Aorta/inervación , Estimulación Eléctrica/métodos , Retroalimentación Fisiológica , Masculino , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY
20.
J Physiol Sci ; 67(5): 587-593, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27660058

RESUMEN

This study examined the mechanism of release of endogenous acetylcholine (ACh) in rabbit renal cortex by applying a microdialysis technique. In anesthetized rabbits, a microdialysis probe was implanted into the renal cortex and perfused with Ringer's solution containing high potassium concentration, high sodium concentration, a Na+/K+-ATPase inhibitor (ouabain), or an epithelial Na+ channel blocker (benzamil). Dialysate samples were collected at baseline and during exposure to each agent, and ACh concentrations in the samples were measured by high-performance liquid chromatography. High potassium had no effect on renal ACh release. High sodium increased dialysate ACh concentrations significantly. Ouabain increased dialysate ACh concentration significantly. Benzamil decreased dialysate ACh concentrations significantly both at baseline and under high sodium. The finding that high potassium-induced depolarization does not increase ACh release suggests that endogenous ACh is released in renal cortex mainly by non-neuronal mechanism. Sodium ion transport may be involved in the non-neuronal ACh release.


Asunto(s)
Acetilcolina/metabolismo , Transporte Iónico/fisiología , Corteza Renal/metabolismo , Sodio/metabolismo , Amilorida/análogos & derivados , Amilorida/farmacología , Animales , Transporte Iónico/efectos de los fármacos , Corteza Renal/efectos de los fármacos , Microdiálisis/métodos , Ouabaína/farmacología , Potasio/metabolismo , Conejos , Canales de Sodio/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Nervio Vago/efectos de los fármacos , Nervio Vago/metabolismo
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