Determination of the refractive index of glucose-ethanol-water mixtures using spectroscopic refractometry near the critical angle.

A spectroscopic refractometer was used to investigate the dispersion curves of ethanol and D-glucose solutions in water near the critical angle; here, the reflectivity was measured using a white source. Dispersion curves were obtained in the 320-1000 nm wavelength range with a resolution better than 10(-4) for the refractive index, n. The differential refractive index is measured as a function of wavelength, and a simple expression is proposed to obtain the refractive index of the glucose-ethanol-water ternary system. Using this expression, combined with the experimental differential refractive index values, the concentrations of individual components can be calculated.

Epidemiología del deterioro intelectual y neurológico progresivo en la infancia. Estudio multicéntrico en la Comunidad Valenciana / Epidemiology of progressive intellectual and neurological deterioration in childhood. A multicentre study in the Community of Valencia

Introducción: El deterioro intelectual y neurológico progresivo (DINP) en la infancia tiene una incidencia de 0,5 por mil nacimientos. Su impacto en lo que a morbimortalidad se refiere es importante. Los objetivos de este trabajo son conocer datos demográficos del DINP, su mortalidad y las principales causas que lo originan. Material y métodos: Se trata de un estudio retrospectivo y multicéntrico llevado a cabo en diferentes hospitales de la Comunidad Valenciana (España). Definición de caso: edad inferior a 18 años con pérdida de habilidades intelectuales o del desarrollo previamente adquiridas de al menos 3 meses de duración. Resultados: Participaron 9 hospitales y se reclutaron un total de 85 casos. La edad media al inicio de los síntomas fue de 1,8 años y al diagnóstico de 3,6. En el 68% de los casos existía un retraso previo al inicio de los síntomas. La mortalidad fue del 16,4%. Se llegó a un diagnóstico en el 74% de los casos. La causa más frecuentemente encontrada fue el síndrome de Rett. El 68% de los casos diagnosticados eran debidos a una metabolopatía. Discusión: La existencia de un retraso del desarrollo previo, así como el inicio tan precoz del proceso, puede dificultar la identificación de un DINP. Al igual que el resto de series, el mayor número de casos diagnosticados corresponde a metabolopatías. Conclusiones: El DINP en la infancia tiene un inicio precoz, con un amplio porcentaje de casos que permanecen sin diagnóstico etiológico y una mortalidad elevada (AU)

Background: Progressive intellectual and neurological deterioration (PIND) in childhood has an incidence of 0.5 per thousand live births. Its impact on morbimortality is important. The aim of this work is to study the epidemiology of PIND and the most important causes of this process. Methods: A retrospective and multicentre study was carried out in different hospitals of the Valencian Community (Spain). Case definition: age less than 18 years with a progressive loss of intellectual or development abilities, previously acquired for at least 3 months. Results: Nine hospitals participated in the study and a total of 85 cases were included. The mean age at the onset of symptoms was 1.8 years, and the mean age at diagnosis was 3.6 years. In 68% of cases there was an intellectual or developmental delay before the onset of symptoms. The mortality rate was 16.4%. A diagnosis was achieved in 74% of the cases. The most frequently found cause was Rett syndrome. More than two-thirds (68%) of diagnosed cases were due to a metabolic disease. Discussion: The existence of a previous development delay and the early onset of the PIND can make it difficult to identify. Like the rest of the series, the largest number of diagnosed cases involved a metabolic disease. Conclusions: PIND has an early onset, and in a large percentage of cases the origin remains unknown and with a high mortality rate (AU)

[Epidemiology of progressive intellectual and neurological deterioration in childhood. A multicentre study in the Community of Valencia]. / Epidemiología del deterioro intelectual y neurológico progresivo en la infancia. Estudio multicéntrico en la Comunidad Valenciana.

BACKGROUND: Progressive intellectual and neurological deterioration (PIND) in childhood has an incidence of 0.5 per thousand live births. Its impact on morbimortality is important. The aim of this work is to study the epidemiology of PIND and the most important causes of this process. METHODS: A retrospective and multicentre study was carried out in different hospitals of the Valencian Community (Spain). CASE DEFINITION: age less than 18 years with a progressive loss of intellectual or development abilities, previously acquired for at least 3 months. RESULTS: Nine hospitals participated in the study and a total of 85 cases were included. The mean age at the onset of symptoms was 1.8 years, and the mean age at diagnosis was 3.6 years. In 68% of cases there was an intellectual or developmental delay before the onset of symptoms. The mortality rate was 16.4%. A diagnosis was achieved in 74% of the cases. The most frequently found cause was Rett syndrome. More than two-thirds (68%) of diagnosed cases were due to a metabolic disease. DISCUSSION: The existence of a previous development delay and the early onset of the PIND can make it difficult to identify. Like the rest of the series, the largest number of diagnosed cases involved a metabolic disease. CONCLUSIONS: PIND has an early onset, and in a large percentage of cases the origin remains unknown and with a high mortality rate.

[The relationship between headache and sleep disorders: findings from an epidemiological study in a population of Spanish school-age children]. / Relación entre cefalea y trastornos del sueño: resultados de un estudio epidemiológico en población escolar.

INTRODUCTION: Headache and sleep disorders have a high impact in children, both from the point of view of prevalence and from the perspective of the quality of life of the subjects who suffer their consequences. AIM. To determine the prevalence of sleep disorders among the child population that suffers from headaches. SUBJECTS AND METHODS: The Spanish version of the Paediatric Sleep Questionnaire was administered to a representative sample of the child and teenage population that attend the different schools in the town of Gandia. This questionnaire includes two questions about the existence of headache. RESULTS: In all, 887 subjects answered the survey (68% of respondents). The sleep disorders that are clearly associated with headache are: rhythmic movement disorders, sleep-talking, nightmares, waking up more than twice during the night, unwillingness to go to bed, early waking, delayed onset of sleep, insomnia, irregular hours of going to bed and getting up, excessive daytime sleepiness, snoring and positive screening for apnea-hypopnea syndrome. CONCLUSIONS: It is shown that the population with headaches has a greater number of sleep disorders, mainly insomnia, excessive daytime sleepiness and parasomnias. It is important to gather information about sleep habits in any child who is attended because of headache.

Relación entre cefalea y trastornos del sueño: resultados de un estudio epidemiológico en población escolar / The relationship between headache and sleep disorders: findings from an epidemiological study in a population of school age children

Introducción. La cefalea y los trastornos del sueño tienen un alto impacto en la población infantil, tanto desde el punto de vista de la prevalencia como desde el punto de vista de la calidad de vida de los sujetos que los presentan. Objetivo. Conocer la prevalencia de los trastornos del sueño entre la población infantil afectada de cefalea. Sujetos y métodos. Se utilizó la versión española del Pediatric Sleep Questionnaire, que se distribuyó entre una muestra representativa de la población de niños y adolescentes que acuden a los diferentes centros escolares de la ciudad de Gandía. Dicho cuestionario incluye dos preguntas acerca de la existencia de cefalea. Resultados. Respondieron a la encuesta un total de 887 sujetos (el 68% de respondedores). Las alteraciones de sueño que se asocian de forma clara con la cefalea son: trastorno del movimiento rítmico, somniloquias, pesadillas, presentar más de dos despertares nocturnos, resistencia a acostarse, despertares tempranos, retraso en el inicio del sueño, insomnio, irregularidad en el horario de levantarse y acostarse, excesiva somnolencia diurna, ronquidos y un cribado positivo para síndrome de apnea-hipopnea. Conclusiones. Se demuestra que la población afectada de cefaleas tiene un mayor número de trastornos del sueño, fundamentalmente insomnio, excesiva somnolencia diurna y parasomnias. Es importante recabar información acerca del sueño en todo niño que sea atendido a causa de cefalea (AU)

Introduction. Headache and sleep disorders have a high impact in children, both from the point of view of prevalence and from the perspective of the quality of life of the subjects who suffer their consequences. Aim. To determine the prevalence of sleep disorders among the child population that suffers from headaches. Subjects and methods. The Spanish version of the Paediatric Sleep Questionnaire was administered to a representative sample of the child and teenage population that attend the different schools in the town of Gandia. This questionnaire includes two questions about the existence of headache. Results. In all, 887 subjects answered the survey (68% of respondents). The sleep disorders that are clearly associated with headache are: rhythmic movement disorders, sleep-talking, nightmares, waking up more than twice during the night, unwillingness to go to bed, early waking, delayed onset of sleep, insomnia, irregular hours of going to bed and getting up, excessive daytime sleepiness, snoring and positive screening for apnea-hypopnea syndrome. Conclusions. It is shown that the population with headaches has a greater number of sleep disorders, mainly insomnia, excessive daytime sleepiness and parasomnias. It is important to gather information about sleep habits in any child who is attended because of headache (AU)

[Attention-deficit/hyperactivity disorder and sleep disturbances. Results of an epidemiological study in schoolchildren in Gandia, Spain]. / Relación entre el trastorno por déficit de atención e hiperactividad y los trastornos del sueño. Resultados de un estudio epidemiológico en la población escolar de la ciudad de Gandía.

INTRODUCTION: The evaluation of comorbidity is an important factor in the treatment of children with attention-deficit/hyperactivity disorder. Sleep disturbances are one of the most common features of this disorder. OBJECTIVE: To find out the frequency of sleep disturbances among children with attention-deficit/hyperactivity disorder. MATERIAL AND METHODS: We used the Spanish version of the Paediatric Sleep Questionnaire, which was given out to a representative sample in Gandia (Spain). RESULTS: The questionnaire was answered by 887 (68 % of the sample). The sleep disturbances that showed a clear relationship with the three ADHD variables studied are: snoring, enuresis, rhythmic movement disturbances, night awakenings, and bedtime resistance. Sleep-disorder breathing, bruxism, somniloquy, day sleepiness, early awakenings and difficulty falling sleep are associated with only one of the three variables studied. CONCLUSIONS: Our study demonstrates that the population with attention-deficit/hyperactivity disorder has more sleep disturbances. The association with the enuresis is of particular interest due to the possible clinical implications.

Relación entre el trastorno por déficit de atención e hiperactividad y los trastornos del sueño. Resultados de un estudio epidemiológico en la población escolar de la ciudad de Gandía / Attention-deficit/hyperactivity disorder and sleep disturbances. Results of an epidemiological study in schoolchildren in Gandia, Spain

Introducción. Uno de los aspectos clave del tratamiento de los niños con trastorno por déficit de atención e hiperactividad (TDAH) es la valoración de la comorbilidad que dicho trastorno presenta. Uno de los trastornos comórbidos que asocia son las alteraciones del sueño. Objetivo. El objetivo de este trabajo es conocer la frecuencia con la que se presentan los trastornos del sueño en la población afectada de TDAH. Material y métodos. Se utilizó la versión española del Paediatric Sleep Questionaire, que se distribuyó entre una muestra representativa de la población de estudiantes de la ciudad de Gandía. El estudio fue aprobado por el Comité de Investigación del hospital. Resultados. Contestaron la encuesta un total de 887 sujetos (68 % de respondedores). Las alteraciones del sueño que se asocian de forma clara con las tres variables del TDAH estudiadas son: ronquido (roncar más de las mitad de la noche), enuresis, trastorno del movimiento rítmico, presentar más de dos despertares nocturnos y resistencia a acostarse. Se relacionan solamente con alguna de las tres variables estudiadas el trastorno respiratorio relacionado con el sueño, bruxismo, somniloquia, excesiva somnolencia diurna, despertares precoces y responder afirmativamente a la pregunta "¿Le cuesta dormirse por la noche?". Conclusiones. Nuestro trabajo demuestra que la población afectada de TDAH tiene un mayor número de trastornos del sueño. De particular interés pensamos que es la relación con la enuresis por las implicaciones clínicas que puede tener

Introduction. The evaluation of comorbidity is an important factor in the treatment of children with attention-deficit/hyperactivity disorder. Sleep disturbances are one of the most common features of this disorder. Objective. To find out the frequency of sleep disturbances among children with attention-deficit/hyperactivity disorder. Material and methods. We used the Spanish version of the Paediatric Sleep Questionnaire, which was given out to a representative sample in Gandia (Spain). Results. The questionnaire was answered by 887 (68 % of the sample). The sleep disturbances that showed a clear relationship with the three ADHD variables studied are: snoring, enuresis, rhythmic movement disturbances, night awakenings, and bedtime resistance. Sleep-disorder breathing, bruxism, somniloquy, day sleepiness, early awakenings and difficulty falling sleep are associated with only one of the three variables studied. Conclusions. Our study demonstrates that the population with attention-deficit/hyperactivity disorder has more sleep disturbances. The association with the enuresis is of particular interest due to the possible clinical implications

Miopatía pseudohipertrófica como manifestación de un hipotiroidismo (síndrome de Kocher-Debré-Semelaigne) / Pseudohypertrophic myopathy as a manifestation of hypothyroidism (Kocher-Debré-Semelaigne syndrome)

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[Sleep patterns and sleep disturbances among schoolchildren in the town of Gandia]. / Patrones normales y trastornos del sueño entre la población escolar de la ciudad de Gandía.

INTRODUCTION: Knowledge of sleep patterns and sleep disturbances among healthy children is interesting, particularly, amongst other things, for carrying out comparative studies with children with certain diseases. The objective of the present study was to study sleep patterns and the prevalence of sleep disturbances among schoolchildren. METHODS: We used the Spanish version of the Pediatric Sleep Questionnaire, which was given out to a representative sample of Gandia Town. RESULTS: The prevalence of sleep disturbances were as follows: insomnia 10.5 %, daytime sleepiness 13 %, a positive score for sleep-disorder breathing 5.7 %, snoring 5.7 %, enuresis 5.3 %, sleepwalking 12.5 %, night terrors 18.4 %, nightmares 12.8 %. As regards sleep patterns, the average time for getting up was 7:45 am, the average time for going to bed was 22:13 pm, and the average sleep duration was 9 hours and 30 minutes. CONCLUSIONS: Comparison among different populations studies is difficult due to the use of different instruments to measure the same variables. Our results are similar to other studies, with the exception of sleep-disorder breathing and snoring, where the prevalences are lower in our study. The sleep patterns also did not show any differences between other published studies.

Patrones normales y trastornos del sueño entre la población escolar de la ciudad de Gandía / Sleep patterns ans sleep disturbances among schoolchildren in the town of Gandia

Introducción: El conocimiento de los patrones de sueño normales y las alteraciones de éste en una población infantil sana tiene interés, entre otras cosas, para poder realizar posteriores análisis comparativos con grupos afectados de determinadas patologías. El objetivo del presente trabajo es, por tanto, conocer los patrones normales de sueño y la prevalencia de los diferentes trastornos de éste en una población escolar. Material y métodos: Se utilizó la versión española del Pediatric Sleep Questionaire, que se distribuyó entre una muestra representativa de la población de estudiantes de la ciudad de Gandía. Resultados: Se encontró una prevalencia de insomnio del 10,5 %, somnolencia diurna del 13,9 %, un cribado positivo para el trastorno respiratorio relacionado con el sueño en el 5,7 %, ronquido en el 4,3 %, enuresis en el 5,3 %, sonambulismo en el 12,5 %, terrores nocturnos en el 18,4 % y pesadillas en el 12,8 %. Respecto a los patrones de sueño, la hora media de levantarse fue las 7:45 h; la de acostarse, las 22:13 h, y la duración media de sueño nocturno de 9 h y 30 min. Conclusiones: La comparación entre estudios poblacionales diferentes es difícil, debido a la utilización de diferentes instrumentos para medir el mismo fenómeno. Nuestros resultados son similares a los de otras series a excepción del trastorno respiratorio relacionado con el sueño y el ronquido, en el que hemos detectado una menor prevalencia de la encontrada en otras series. Los hábitos de sueño tampoco difieren mucho de otras series publicadas (AU)

Introduction: Knowledge of sleep patterns and sleep disturbances among healthy children is interesting, particularly, amongst other things, for carrying out comparatives studies with children with certain diseases. The objective of the present study was to study sleep patterns and the prevalence of sleep disturbances among schoolchildren. Methods: We used the Spanish version of the Pediatric Sleep Questionnaire, which was given out to a representative sample of Gandia Town. Results: The prevalence of sleep disturbances were as follows: insomnia 10.5 %, daytime sleepiness 13 %, a positive score for sleep-disorder breathing 5.7 %, snoring 5.7 %, enuresis 5.3 %, sleepwalking 12.5 %, night terrors 18.4 %, nightmares 12.8 %. As regards sleep patterns, the average time for getting up was 7:45 am, the average time for going to bed was 22:13 pm, and the average sleep duration was 9 hours and 30 minutes. Conclusions: Comparison among different populations studies is difficult due to the use of different instruments to measure the same variables. Our results are similar to other studies, with the exception of sleep-disorder breathing and snoring, where the prevalences are lower in our study. The sleep patterns also did not show any differences between other published studies (AU)

Point mutation of an EYA1-gene splice site in a patient with oto-facio-cervical syndrome.

Mutations of the EYA1 gene (8q13.3) are the most common known cause of the branchio-oto-renal dysplasia (BOR), an autosomal dominant disease that includes developmental defects of branchial arch structures, middle and/or inner ear and kidney. The distinction between BOR and other dysplasias, such as oto-facio-cervical syndrome (OFC), is challenged by frequent association of the former to other diverse malformations, and by variable expressivity even within the same family. OFC is characterized by trophic alterations of the facies and shoulder girdle in addition to the malformations seen in BOR. Recent characterization of one OFC patient shed some light on the controversy over whether OFC and BOR are the same disease, and led to the hypothesis that OFC is caused by contiguous deletions of EYA1 and adjacent genes. By contrast, we show here that an OFC patient bears a single-nucleotide substitution in a splice site of EYA1. Our results indicate that not only major rearrangements, but also point mutations altering the EYA1 reading frame, can be found in patients with OFC syndrome.

Lectin histochemistry of foam cells in tissues of cattle grazing Brachiaria spp.

Brachiaria decumbens and B. brizantha (signal grass), which occupy millions of acres in Brazil, are an important source of fodder for ruminants. Sporadic outbreaks of photosensitization in ruminants grazing on signal grass have been reported. Intoxicated animals showed the presence of foamy cells in the liver, spleen, intestinal submucosa and lymph nodes. These foamy cells are macrophages. They are very difficult to distinguish with haematoxylin and eosin stain, especially in the case of isolated cells. The purpose of the present study was to detect specific carbohydrate residues of storage material in the foamy cells in tissues of cattle exposed to Brachiaria spp. The characterization of glycoconjugates provides clues to the pathogenesis of these cells. Besides, the lectin peanut agglutinin was found to be an excellent marker to differentiate and quantify the foam cells, and could be used as a specific marker.

Effects of plant-induced hypervitaminosis D on cutaneous structure, cell differentiation and cell proliferation in cattle.

Solanum glaucophyllum (Sg) (synonym S. malacoxylon) is a plant toxic to cattle due to its high levels of 1,25-dihydroxyvitamin D3 as glycoside derivatives. Sg causes a disease characterized by wasting and calcification of soft tissues. The effects of vitamin D are not only important in calcium homeostasis, but also in immune regulation, cell growth and cell differentiation. Skin samples in Sg-intoxicated and control heifers were studied histologically. Cellular differentiation and proliferation were analysed by immunohistochemical expression of cytokeratins, involucrin and proliferating cell nuclear antigen (PCNA). The results were obtained by image processing and analysis and were statistically evaluated. Sg-intoxicated cattle showed atrophy of epidermis and severe involution of hair follicles and of sebaceous and sweat glands. As judged by PCNA expression, cellular proliferation was reduced, even though the reduction was not statistically significant. The analysed markers of differentiation, e.g. involucrin and cytokeratins 10 and 11, changed in relation to Sg-poisoning. The possible pathogenesis of the skin lesions is discussed.

Reflectivity of a gaussian beam near the critical angle with external optically absorbing media.

One can use the angle-modulated reflectance of a gaussian beam near the critical angle to sense with high resolution the index of refraction of the external medium. We analyze in detail the reflectivity of a gaussian beam near the critical angle and its dependence on the optical absorption of the external medium. The given formulation is relatively simple and is useful in discerning the effects of the various parameters involved on the reflectivity and its differentials with respect to the angle of incidence. The results presented can be readily used for the quantitative design of novel sensors based on modulated reflectance near the critical angle. We provide a simple algebraic expression for the loss of sensitivity of modulated reflectance near the critical angle as the sample's absorption coefficient increases. We find that, in a typical case, the sensitivity has decreased to approximately half its value for transparent samples when the absorption coefficient has increased to 25 cm(-1). We conclude that modulated reflectance near the critical angle remains a competitive technique for monitoring the index of refraction of an external medium with an absorption coefficient of as much as 120 cm(-1). We compared experimentally obtained curves of the first differential of the reflectivity with respect to the angle of incidence with theory and found good agreement.

Participation of ACTH1-10 and ACTH4-10 on the melatonin modulation of benzodiazepine receptors in rat cerebral cortex.

In this study, we examined the effect of intracerebroventricular (i.c.v) injection of melatonin and/or ACTH1-10 and ACTH4-10 on [3H]flunitrazepam binding sites in the cerebral cortex of hypophysectomized rats. Hypophysectomy increased the Bmax (maximum number of binding sites) of benzodiazepine (BNZ) receptors for at least 7 days after surgery, without changing KD (dissociation constant). The i.c.v. injection of melatonin to hypophysectomized rats significantly increased Bmax, whereas the same doses of melatonin were ineffective in sham-operated animals. In both cases, KD values were unchanged. The i.c.v. injection of ACTH1-10 to hypophysectomized animals significantly increased Bmax, an effect that was enhanced by simultaneous i.c.v. injection of ACTH1-10 + melatonin, reaching higher values of Bmax than the i.c.v. injection of these hormones individually. No significant changes in KD values were found after ACTH1-10 and/or melatonin administration. However, the i.c.v. injection of ACTH4-10 to hypophysectomized rats did not change Bmax, although it significantly increased KD values, indicating a decrease in the BNZ binding affinity. Melatonin injection counteracted this effect of ACTH4-10, returning KD to the control value. Moreover, although the lower dose of i.c.v. melatonin used, 10 ng, was unable to modify Bmax of BNZ binding in the ACTH4-10-injected group, the higher dose, 20 ng, significantly increased Bmax. The results suggest that these ACTH-derived peptides can modulate the effect of melatonin on brain benzodiazepine receptors.

Influence of the behaviorally active peptides ACTH1-10 and ACTH4-10 on the melatonin modulation of 3H-flunitrazepam receptor binding in the rat cerebral cortex.

Possible interactions of ACTH-like peptides with melatonin regulation of central-type benzodiazepine (BNZ) receptors have been studied by means of high-affinity 3H-flunitrazepam binding to rat cerebral cortex membrane preparations. Intracerebroventricular injections of melatonin produce a dose-dependent increase in Bmax in pinealectomized rats, without changes in KD. Analogous effects were obtained after intracerebroventricular injection of melatonin in adrenalectomized and in adrenalectomized plus pinealectomized rats, which indicated the lack of participation of adrenal steroids in this response. Moreover, intracerebroventricular injection of ACTH1-10 induced a similar dose-dependent increased Bmax in sham-operated animals, whereas pinealectomy, but not adrenalectomy, partially counteracted this effect of ACTH1-10 administration. Besides, simultaneous injection of ACTh1-10 plus melatonin reverses the effects of pinealectomy, resulting in an additive effect of both compounds on Bmax. The response obtained when using ACTh4-10 was somewhat different, because no dose response was obtained in any experiment. Although lack of endogenous melatonin partially reduced the increasing effect of ACTH4-10 on Bmax, there were no additive effects at the different doses used. The results strongly suggest that ACTH-like peptides, in addition to melatonin, play a role in regulating central-type rat BNZ receptors.

Melatonin counteracts pinealectomy-dependent decreases in rat brain [3H]flunitrazepam binding through an opioid mechanism.

The effect of intracerebroventricular (i.c.v.) injection of melatonin and/or beta-endorphin on the [3H]flunitrazepam binding sites in the cerebral cortex of pinealectomized or superior cervical ganglionectomized rats was studied. Pinealectomy decreased the maximum concentration of benzodiazepine receptors (Bmax) without affecting the dissociation constant (KD), while melatonin, ineffective in control animals, counteracted the effect of pinealectomy. Intracerebroventricular injection of beta-endorphin increases Bmax in both control and pinealectomized animals, the effect being significantly higher in the latter. Simultaneous i.c.v. injection of melatonin + beta-endorphin did not further increase Bmax in any group, whereas i.c.v. injection of naloxone significantly blocked the effects of melatonin and/or beta-endorphin administration. Pineal sympathetic denervation produced a significant increase in Bmax and KD, whereas i.c.v. injection of melatonin further increased the former, restoring KD to control values. Neither i.c.v. administration of beta-endorphin or melatonin + beta-endorphin significantly modified the ganglionectomy-dependent increase in Bmax, although both treatments restored KD to control values. Naloxone administration had no effect on beta-endorphin- and melatonin + beta-endorphin-treated ganglionectomized groups, but counteracted the increased effect of melatonin on Bmax in ganglionectomized animals.