Circuit-Specific Control of Blood Pressure by PNMT-Expressing Nucleus Tractus Solitarii Neurons / 神经科学通报·英文版

The nucleus tractus solitarii (NTS) is one of the morphologically and functionally defined centers that engage in the autonomic regulation of cardiovascular activity. Phenotypically-characterized NTS neurons have been implicated in the differential regulation of blood pressure (BP). Here, we investigated whether phenylethanolamine N-methyltransferase (PNMT)-expressing NTS (NTSPNMT) neurons contribute to the control of BP. We demonstrate that photostimulation of NTSPNMT neurons has variable effects on BP. A depressor response was produced during optogenetic stimulation of NTSPNMT neurons projecting to the paraventricular nucleus of the hypothalamus, lateral parabrachial nucleus, and caudal ventrolateral medulla. Conversely, photostimulation of NTSPNMT neurons projecting to the rostral ventrolateral medulla produced a robust pressor response and bradycardia. In addition, genetic ablation of both NTSPNMT neurons and those projecting to the rostral ventrolateral medulla impaired the arterial baroreflex. Overall, we revealed the neuronal phenotype- and circuit-specific mechanisms underlying the contribution of NTSPNMT neurons to the regulation of BP.

Crisis suprarrenal: prevención, corticoterapia y elección del fármaco, revisión de la evidencia actual y recomendaciones / Adrenal crisis: prevention, corticotherapy and choice of the drug, review of current evidence and recommendations

INTRODUCCIÓN. La crisis suprarrenal se refiere a la insuficiencia suprarrenal aguda; la cual es un trastorno en el que la corteza adrenal no produce suficientes hormonas esteroides (en especial cortisol) para satisfacer las demandas del cuerpo, de acuerdo al mecanismo fisiopatológico se la puede clasificar como primaria, secundaria y terciaria, siendo más común en pacientes con insuficiencia suprarrenal primaria. Es una emergencia potencialmente mortal que requiere tratamiento inmediato. OBJETIVO. Establecer una estrategia de prevención y tratamiento de la crisis suprarrenal, así como la farmacoterapia ideal y sus alternativas válidas. MATERIAL Y MÉTODOS. Se realizó una revisión bibliográfica en varias revistas virtuales de alto carácter científico como Cochrane Library, Cochrane Systematic Reviews Database, MEDLINE a través de PubMed y ClinicalTrial.gov. Se seleccionaron revisiones sistemáticas con o sin metaanálisis, ensayos clínicos y recomendaciones de expertos relacionados con prevención y tratamiento de crisis suprarrenal en general. RESULTADOS. Se obtuvieron 1819 resultados, de los cuales se seleccionaron 20 artículos con mayor validez y replicabilidad en el medio para establecer un protocolo unificado de actuación. CONCLUSIÓN. El objetivo de la terapia es el tratamiento de la hipotensión y reversión de las anomalías electrolíticas y de la deficiencia de cortisol. Se deben infundir por vía intravenosa grandes volúmenes (1 a 3 litros) de solución salina al 0,9% o dextrosa al 5% en solución salina al 0,9% y la administración de hidrocortisona (bolo de 100 mg), seguido de 50 mg cada 6 horas (o 200 mg / 24 horas como infusión continua durante las primeras 24 horas). Si no se dispone de hidrocortisona, las alternativas incluyen prednisolona, prednisona y dexametasona.

INTRODUCTION. Adrenal crisis refers to acute adrenal insufficiency; which is a disorder in which the adrenal cortex does not produce enough steroid hormones (especially cortisol) to meet the body's demands, according to the pathophysiological mechanism it can be classified as primary, secondary and tertiary, being more common in patients with primary adrenal insufficiency. It is a life-threatening emergency that requires immediate treatment. OBJECTIVE. To establish a strategy for the prevention and treatment of adrenal crisis, as well as the ideal pharmacotherapy and its valid alternatives. MATERIAL AND METHODS. A literature review was performed in several highly scientific virtual journals such as Cochrane Library, Cochrane Systematic Reviews Database, MEDLINE through PubMed and ClinicalTrial.gov. Systematic reviews with or without meta-analysis, clinical trials and expert recommendations related to prevention and treatment of adrenal crisis in general were selected. RESULTS. A total of 1819 results were obtained, from which 20 articles with greater validity and replicability in the setting were selected to establish a unified protocol for action. CONCLUSIONS. The aim of therapy is the treatment of hypotension and reversal of electrolyte abnormalities and cortisol deficiency. Large volumes (1 to 3 liters) of 0.9% saline or 5% dextrose in 0.9% saline and administration of hydrocortisone (100 mg bolus), followed by 50 mg every 6 hours (or 200 mg / 24 hours as a continuous infusion for the first 24 hours) should be infused intravenously. If hydrocortisone is not available, alternatives include prednisolone, prednisone, and dexamethasone.

Effect of immobilization stress on gene expression of catecholamine biosynthetic enzymes in heart auricles of socially isolated rats

Chronic stress is associated with the development of cardiovascular diseases. The sympathoneural system plays an important role in the regulation of cardiac function both in health and disease. In the present study, the changes in gene expression of the catecholamine biosynthetic enzymes tyrosine hydroxylase (TH), dopamine-â-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) and protein levels in the right and left heart auricles of naive control and long-term (12 weeks) socially isolated rats were investigated by Taqman RT-PCR and Western blot analysis. The response of these animals to additional immobilization stress (2 h) was also examined. Long-term social isolation produced a decrease in TH mRNA level in left auricles (about 70 percent) compared to the corresponding control. Expression of the DBH gene was markedly decreased both in the right (about 62 percent) and left (about 81 percent) auricles compared to the corresponding control, group-maintained rats, whereas PNMT mRNA levels remained unchanged. Exposure of group-housed rats to acute immobilization for 2 h led to a significant increase of mRNA levels of TH (about 267 percent), DBH (about 37 percent) and PNMT (about 60 percent) only in the right auricles. Additional 2-h immobilization of individually housed rats did not affect gene expression of these enzymes in either the right or left auricle. Protein levels of TH, DBH and PNMT in left and right heart auricles were unchanged either in both individually housed and immobilized rats. The unchanged mRNA levels of the enzymes examined after short-term immobilization suggest that the catecholaminergic system of the heart auricles of animals previously exposed to chronic psychosocial stress was adapted to maintain appropriate cardiovascular homeostasis.

Association of genetic polymorphism in phenylethanolamine-N-methyl transferase with essential hypertension in Changsha Han people / 中南大学学报(医学版)

OBJECTIVE@#To investigate the association of phenylethanolamine-N-methyl transferase (PNMT) G-390A genetic polymorphism with risk of essential hypertension (EH) in Changsha Han people.@*METHODS@#A case-control association study was performed in 400 patients with essential hypertension (EH) and 388 normotensive subjects. PNMT G-390A was genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-FRLP).@*RESULTS@#The genotype frequencies for the -390 GG, GA, and AA were 39.3%,50.0%, and 10.8%, respectively in EH patients, and were 43.6%,45.6%, and 10.8%, in normal subjects. No significant difference in either genotypic frequency (P=0.433) or allele frequency (P=0.378) of PNMT G-390A between EH patients and normals was observed. When by gender, there was significant difference in genotypic frequency (P0.05).@*CONCLUSION@#PNMT G-390A polymorphism is possibly associated with EH risk in male Chinese Han population in Changsha.

Immunochemical localization of chromaffin cells during the embryogenic migration

Adrenal medulla together with the sympathetic nervous system constitute an anatomo functional unit. Both tissues derive from precursor cells which originate from the neural crest and later differentiate during migration into sympathetic neurons or chromaffin cells. Biosynthesis enzymes of catecholamines such as DBH (dopamine beta hydroxylase) and PNMT (phenylethanol amine-N-methyl transferase) as well as the neurotransmitter serotonin , can be detected by immunohistochemical techniques from 15 to 20 prenatal days. Cells migrating along the dorsal aorta could be observed at 15 prenatal days. From day 16 on, three distinct cellular groups could be distinguished according to the intensity of the immunoreactivity: chromaffin, paraganglion and sympathetic ganglion cells. From day 18, chromaffin cells immunostained as DBH' PNMT+ or DBH+ PNMT could be detected differentiating into what would be adrenergic or noradrenergic cells, respectively Progenitor cells migrating from the neural crest to the adrenal cortical blastema reach a micro-environment where glucocorticoids could possibly influence gene expression for PNMT in some of these undifferentiated cells, causing adrenaline synthesis. Serotonin(5HT) immunoreactivity is localized from 17 prenatal days in several groups of the paraganglionic cells where they could be a modulator for chromaffin differentiation.