Neurophysiological, cognitive-behavioral and neurochemical effects in practitioners of transcendental meditation - A literature review

SUMMARY The term meditation can be used in many different ways, according to the technique to which it refers. Transcendental Meditation (MT) is one of these techniques. TM could serve as a model for research on spiritual meditation, unlike the meditation techniques based on secular knowledge. The purpose of the present study is to conduct a bibliographic review to organize scientific evidence on the effects of TM on neurophysiology, neurochemistry, and cognitive and behavioral aspects of its practitioners. To conduct this critical narrative review of the literature, we searched for scientific papers on the PubMed database of the National Center for Biotechnology Information. The keywords used in the search were Transcendental Meditation, Neuroscience of meditation e Meditation and behavior. We selected 21 papers that analyzed different aspects that could be altered through meditation practice. We concluded that TM has positive and significant documentable neurochemical, neurophysiological, and cognitive-behavioral effects. Among the main effects are the reduction of anxiety and stress (due to the reduction of cortisol and norepinephrine levels), increase of the feeling of pleasure and well-being (due to the increase of the synthesis and release of dopamine and serotonin), and influence on memory recall and possible consolidation. Further studies are needed using creative and innovative methodological designs that analyze different neural circuitry and verify the clinical impact on practitioners.

RESUMO O termo meditação pode ser utilizado de diversas formas, de acordo com a técnica a que se refere. A meditação transcendental (MT) é uma dessas técnicas meditativas. A MT pode ser um modelo para pesquisas de meditação espiritual, diferentemente de técnicas de meditação baseadas em uma compreensão secular. O presente estudo objetiva realizar uma revisão bibliográfica para organizar as evidências científicas sobre os efeitos da MT sobre a neurofisiologia, neuroquímica e aspectos cognitivos e comportamentais dos seus praticantes. Para a realização desta revisão narrativa crítica da literatura, foi realizado um levantamento dos artigos científicos presentes na base de dados PubMed do National Center for Biotechnology Information. As palavras-chave utilizadas na busca foram Transcendental Meditation, Neuroscience of meditation e Meditation and behavior. Foram selecionados 21 artigos que analisavam diferentes aspectos que poderiam ser alterados pela prática meditativa. Conclui-se que a MT produz efeitos neuroquímicos, neurofisiológicos e cognitivo-comportamentais documentáveis em seus praticantes, de caráter positivo e significativo. Entre os principais efeitos estão a diminuição da ansiedade e do estresse (via diminuição nos níveis de cortisol e noradrenalina), aumento na sensação de prazer e bem-estar (em decorrência ao aumento na síntese e liberação de dopamina e serotonina) e influência na evocação e possível consolidação da memória. São necessários mais estudos utilizando desenhos metodológicos inovadores e criativos, analisando diferentes circuitos neurais e verificando o impacto clínico sobre os praticantes.

Serum zinc level in children with febrile convulsion and its comparison with that of control group

Febrile convulsion is the most common disorder in childhood with good prognosis. There are different hypotheses about neurotransmitters and trace element [such as zinc] changes in cerebrospinal fluid and serum, which can have a role in pathogenesis of febrile convulsion. The aim of the present prospective analytical case-control study was to determine whether there was any changes in serum zinc level in children with febrile convulsion during seizure. Ninety-two children aged 6 months to 5 years were divided into three groups: group A, 34 children with febrile convulsion, group B, 40 children having fever without convulsion, and group C, and 18 children with non-febrile convulsion. Serum zinc levels for the three groups were estimated by atomic absorption spectrophotometry [AAS]. Data were analyzed to compare zinc level among the three groups using appropriate statistical tools employing SPSS 13. Serum zinc levels of groups A, B, and C had a mean value of 76.82 +/- 24.36mg/1, 90.12 +/- 14.63 mg/1 and 94.53 +/- 17.39 mg/l, respectively. Serum zinc level of group A was lower than those of the other two groups [P < 0.006]. It was also lower in group B than in group C [P < 0.006]. These findings revealed that serum zinc level decreases during infection; this decrease was more significant in patients with febrile convulsion

Mecanismos neuroendócrinos envolvidos na puberdade de novilhas / Neuroendocrine mechanisms in puberty heifers / Mecanismos neuroendocrinos involucrados en la pubertad de novillas

Sob o ponto de vista fisiológico, a puberdade em novilhas Bos taurus e Bos indicus caracteriza-se por um aumento na concentração e freqüência pulsátil de LH e um decréscimo na sensibilidade do hipotálamo aos esteróides gonadais, com participação ou não de neurotransmissores com capacidade de estimular ou inibir a secreção de LH, o que resultará na primeira ovulação. Os eventos fisiológicos relacionados à primeira ovulação são similares, tanto nas novilhas Bos taurus, quanto nas novilhas Bos indicus, ocorrendo mais tardiamente nesta última. O sistema extensivo de criação do Zebu, adotado na maioria dos países sul-americanos, contribui para que a puberdade aconteça mais tardiamente, refletindo na idade ao primeiro parto. A idade à primeira ovulação é uma característica de alta herdabilidade, sendo a seleção genética, através da precocidade sexual, uma ferramenta para reduzir a idade ao primeiro parto e melhorar a eficiência reprodutiva do sistema de produção. Aliado à seleção genética, o uso de técnicas de manejo melhorando a qualidade nutricional e a oferta de alimentos, o cruzamento entre raças, a exposição das novilhas a touros e o uso de biotecnologias que permitam manipular a primeira ovulação, podem contribuir para o aumento da produtividade. Esta revisão tem como objetivo abordar aspectos fisiológicos relacionados à puberdade de novilhas Bos taurus e Bos indicus.

Under a physiological perspective, puberty in both Bos taurus and Bos indicus heifers is characterized by an increase in the LH concentration, frequency pulses, and decreasing of the hypothalamic-pituitary axis sensibility to gonadal steroid, with, or without, the participation of the neurotransmitters capable of either stimulating or to inhibiting the LH secretion, which will result in the first ovulation. The physiological events related to the first ovulation are similar for both Bos taurus and Bos indicus, occurring later for Bos indicus. The extensive Zebu management carried out in the majority of the South American countries contributes for puberty to occur later influencing the age of the first calving. Regarding the first ovulation, age is a characteristic of high heritability, as the genetic selection, through sexual precocity, is a tool for first¬calving age reduction; and the improvement of the nutritional quality and feeding supply, crossbreeding, heifer exposition to bulls and the use o biotechnologies which ensure the manipulation of the first ovulation might contribute for the productivity increasing. This review aims at approaching physiological aspects related to the puberty of both Bos taurus and Bos indicus heifers.

Detection of amino acids in human nasal mucosa using microdialysis technique: increased glutamate in allergic rhinitis.

Amino acids, the smaller basic biochemical units of neuropeptides, have not been evaluated in the nasal cavity. The purpose of this study was to measure the concentration of neurotransmitting amino acids of the central nervous system, glutamate, aspartate, serine, taurine (2-aminoethane sulfonic acid; a conditionally essential amino acids), and GABA (gamma-amino-butyric acid; an amino acid produced in the brain), in nasal mucosa of allergic rhinitis patients and normal controls using a microdialysis technique. A microdialysis probe appropriate for use on human nasal mucosa was developed using Cuprophan hollow fiber. Glutamate concentration in allergy group was significantly higher (p = 0.004) than in control group, while the concentrations of the other four amino acids showed no significant difference between the two groups. Our findings and review of the literature suggest that glutamate is one of the most potent neurotransmitters associated with the parasympathetic nerve in the nasal cavity, and that the microdialysis technique is useful in studying the pharmacokinetics in situ and local organ chemistry of the nasal cavity.

Níveis dos neurotransmissores estriatais durante o estado epiléptico / Striatal monoamines levels during status epilepticus

O objetivo desse estudo foi verificar os níveis dos neurotransmissores estriatais de ratas adultas durante o estado epiléptico induzido pela pilocarpina. Ratas wistar foram tratadas com uma única dose de pilocarpina (400 mg/kg por via subcutânea (S.C.); P400) e os controles receberam salina. A concentração dos neurotransmissores foi determinada através do HPLC eletroquímico, no corpo estriado de ratas que no período de observação de 1 hora desencadearam estado epiléptico e que sobreviveram à fase aguda do quadro convulsivo. Foi observada redução nos níveis de dopamina, serotonina, ácido diidroxifenilacético e aumento na concentração do ácido 5-hidroxiindolacético. Nenhuma alteração foi observada no 4-hidroxi-3-metoxi-fenilacético. Os resultados sugerem que a ativação do sistema colinérgico pode interagir com os sistemas dopaminérgico e serotonérgico nos mecanismos referentes à fase aguda do processo convulsivo no corpo estriado de ratos desenvolvidos.

As bases biologicas do transtorno de panico / The biological basis of panic disorder

O transtorno do panico e uma condicao clinica complexa que envolve fatores biologicos e psicossociais na genese de seus sintomas. Este artigo reve brevemente modelos biologicos e neuroquimicos...

Studies on the changes of c-fos protein in spinal cord and neurotransmitter in dorsal root ganglion of the rat with an experimental peripheral neuropathy

Animal models for human chronic pain syndromes have been developed and widely used for pain research. One of these neuropathic pain models by Kim and Chung (1992) has many advantages for operation and pain elicitation. In this neuropathic model we have examined the c-fos protein, substance P, CGRP immunoreactivity in dorsal root ganglia and dorsal horn. 50 Sprague-Dawley rats were used for this study. L5 and L6 spinal nerves were ligated tightly to produce the neuropathic pain model. After 2, 4, 8, 16, and 24 hours and 1 week of surgery, rats were anesthetized and sacrificed by perfusion. After confirmation of the roots transected by the surgery, the L5 and L6 dorsal root ganglions and spinal cord were removed and processed for immunohistochemistry. All tissue sections were immunohistochemically stained for substance P, CGRP and c-fos using the peroxidase-antiperoxidase (PAP) method. The number of immunostained substance P and CGRP dorsal root ganglion cells and c-fos immunoreactive dorsal horn cells were counted and analyzed statistically with Mann-Whitney U test. The results are as follows. The number of c-fos protein immunoreactive neurons in the superficial layer of dorsal horn were increased markedly 2 hours after operation, and gradually decreased to normal level 1 week after operation. The number of c-fos protein immunoreactive neurons in the deep layer of the dorsal horn gradually increased to a peak 24 hours after operation, then decreased to the normal level 1 week after operation. The number of substance P and CGRP immunoreactive L5 and L6 dorsal root ganglion neurons were decreased markedly 1 week after the pain model operation. In conclusion, after neuropathic pain model operation, c-fos proteins were immediately expressed in the superficial layer of spinal dorsal horn, thereafter c-fos proteins in the deep layer of spinal dorsal horn were expressed. CGRP and substance P immunoreactive neurons in DRG were decreased markedly 1 week after neuropathic pain model operation. These decrements do not coincide with the other chronic pain models, which show great increases in these pain transmitting substances. Therefore, the relationship between pain and c-fos, SP and CGRP should be investigated further.

Elevación de la fracción libre de L-triptófano plasmático en lactantes desnutridos in utero hasta el tercer mes de edad postnatal / Increased levels of free plasma L-trypthophan in nursing infants with malnutrition in utero up to the third month of extra-uterine life

Introducción. Se ha demostrado en la rata que la desnutrición adquirida durante la gestación y en la lactancia produce elevación del L-Triptófano (L-Trp) tisular y de la actividad de la triptófano-5-hidroxilasa (TrpOH), que da como resultado una aceleración de la síntesis de 5-hidroxitriptamina (5-HT, serotonina). Este cambio metabólico parece también cumplirse en los recién nacidos humanos desnutridos in utero, en cuyo plasma aumenta la fracción libre del L-Trp y disminuye el unido a albúmina, lo que sugiere que hay más L-Trp disponible para pasar al cerebro humano y aumentar la síntesis del neurotransmisor. El objetivo del presente estudio fue demostrar que la fracción libre de L-Trp plasmático, está aumentada hasta el tercer mes de edad en los lactantes desnutridos in utero. Material y métodos. Se realizó un estudio prospectivo longitudinal y comparativo, con el seguimiento de 2 grupos de recién nacidos pretérmino de 33 a 36 semanas de edad gestacional; un grupo de 11 niños desnutridos y el otro de 14 niños sanos; durante los primeros 3 meses de vida en los que se determinó la fracción libre y la unida a albúmina de L-Trp, así como la 5-HT y la albúmina en el plasma. Los resultados fueron comparados con la prueba de anova de dos vías para mediciones repetidas y el coeficiente de Pearson; con un nivel de significancia de P menor de 0.05. Resultados. En los lactantes desnutridos, al nacimiento, al primero, segundo y tercer mes de edad se observó: a) elevación de la fracción libre del L-Trp; b) la fracción unida o albúmina del aminoácido y la albúmina en el plasma fueron significativamente menores en comparación a sus controles de la misma edad y c) la concentración de 5-HT plásmatica mostró disminución significativa en los desnutridos a partir del segundo mes de edad. Conclusiones. Los resultados de este estudio confirman que la fracción libre del L-Trp está significativamente elevada en los lactantes desnutridos in utero durante los primeros tres meses de vida. El aumento de L-Trp en el plasma sugiere que el transporte del aminoácido al cerebro está aumentado y que hay activación en la síntesis de serotonina cerebral. Por lo anterior se ha propuesto en la síntesis de serotonina cerebral. Por lo anterior se ha propuesto en este estudio a la fracción libre de L-Trp plasmático como un indicador indirecto de la alteración en la síntesis de serotonina cerebral en este tipo de pacientes

El efecto de un "neurotónico" popular sobre la velocidad de conducción nerviosa periférica y tiempo de conducción del sistema nerviosa central / Effect of a popular neurotonic on peripheral nerve conduction and time conduction and central nervous system

Nuestra población es llevada por la propaganda a consumir productos que argumentan combatir la fatiga, la debilidad nerviosa, mental y muscular, disminución de la capacidad intelectual, depresión psíquica, proporcionando deseos de trabajar y estudiar, reactiva la memoria, aumenta la capacidad de concentración, y mejorar la capacidad mental, los cuales hemos denominado "NEUROTONICOS". Evaluamos el efecto de los neurotónicos (CERENERVON), usando 2 médidas estándar de la función nerviosa, la velocidad de conducción periférica del nervio cubital y el tiempo de conducción del sistema nervioso central (SNC) por medio de potenciales evocados somatosensoriales (PESS)

Brain monoamines during footshock-induced aggression in paired rats.

Regional brain monoamine concentrations were investigated following footshock induced fighting behaviour in paired rats, by a spectrophotofluorometric method. The dopamine (DA) levels of the diencephalon-midbrain (DM), and that of the caudate nucleus (CN), were significantly augmented as compared to unshocked but paired rats, the increase being substantially more in DM. Noradrenaline (NA) concentrations of both DM and pons-medulla (PM) increased to almost similar extents, though the data remained statistically insignificant in comparison to controls. The 5-hydroxytryptamine (5HT) of both DM and PM, however, recorded a decrease, which was statistically significant in the latter brain area. The biochemical data are consonant with the reported facilitatory effect of central DA, and the inhibitory role of central 5HT, in experimental aggression. The observed changes in NA levels, for which a role in experimental aggression remains equivocal, may be due to the stress of footshock kept minimal due to the coping factor of fighting in response to the shock.