Archivos de neurobiologia最新文献

This work is a review about psychoendocrinologic aspects of aggressive behavior. We have considered two approaches, the classical view focused on hormonal influences in the regulation of aggression and the most recent view which accounts for the influences of aggressive behavior and social status on hormonal secretion. In this review we differentiate the organizational from the activational effects. The main conclusions are referred to the gonadal steroids effects both organization and activation of the neural subtract of aggression. Among them it seems that aromatizable androgens have the most important effects. On the other hand, the testosterone would be predictive for dominant social status, the corticosterone would be for submission and finally, the ACTH would be predictive for the aggressive behavior but not for submission. In addition to that the literature point that the defeat experience is the main factor in submission. Referred to the effects of behavior on hormonal secretions, all the studies point out that social interaction elicits sympathetic-medullar and gonadal activation in the dominant animals and cortico-adrenal activation in the submissive ones.

Blink reflex (BR) and brainstem auditory evoked potentials (BAEP) were recorded from 168 patients with several diagnostic categories of multiple sclerosis, from which 98 complained brainstem symptoms (BSS+). From the whole group, the BR showed a higher degree of abnormality (45.75%) than BAEP (27.95). This range increased in the group BSS+ (52.15% for the BR and 34.9% for the BAEP) and even more when sings or symptoms of brainstem were present at the time of exploration (BSS+P) 60.4% for the BR and 41.3% for BAEP. Among patients who never complained brainstem symptoms, the BR disclosed a subclinical lesion in the 33.3% and the BAEP in the 16.9%. The combination of BR and BAEP were more useful than an isolated test. The localization of the lesion both clinically and in the BR were mostly on the pons. Light correlation between the presence of isolated or multiple symptoms and the disorder in the BR were present. Facial myokymia and internuclear ophthalmoplegia were most often associated with disorder in the BR, in both, the commonest localization was on the pons, and in the former about the motor nucleus of the facial nerve.

This paper analyses the relationship between oral and axillary temperatures in the waking part of the day, and verify the existence of sex differences within both parameters. We selected 20 healthy subjects (10 men and 10 women) aged 22 to 30, controlling environmental and subject variables. The women's group does show greater thermic values for axillary temperature (8 of the 13 recordings). There was a highly correlation between sex groups (r = 0.854, p less than 0.001), axillary temperature rhythms between sexes are coupled and any differences are only of degree. For oral temperature the women's group showed higher values in 3 recordings (15.00, 18.00 and 21.00), and there was no correlation between men and women throughout the day. These results evidence sex differences in rhythmic patterns of oral temperature. Correlations between temperatures were highly positive for the whole sample, men and women. Our study presents empirical data on the validity of using axillary temperature as alternative measurement of body temperature. We expect the use of axillary temperature to be increasingly employed in chronobiological field studies.

Acetylcholinesterase (AChe) hydrolyses acetylcholine to choline and acetate, thereby inactivating the neurotransmitter. However, the possible non-cholinergic function of this enzyme has been recently suggested. In the present work, changes in AChe activity during the postnatal development of the cat brain are described, in order to show if the enzyme could play a part in the maturing processes of the CNS. The study was performed in the frontal and parietal cortices, area 17 and areas 18 and 19 as a whole in the 15 and 30 days postnatal stages. Significant increases with age were observed in all the brain areas under study. It is suggested that this enzyme activity play a part in the maturation of the cat brain cortices, possibly in the cholinergic development and/or as a cell growth regulatory factor.

This paper concerns the influence of the acupuncture on the somatic afferent volley. As the main used points in experimental acupuncture, we stimulated 4GI and 7H. The results confirm the modulatory influence of the acupuncture on the somesthetic afference and, also, its different mode of action related with the nature of the point stimulated.

Background: Use of an experimentally induced neurotoxic lesion of the ascending cholinergic pathway to the neocortex, in rat brain, to study the postulated selective loss of muscarinic receptor subtypes (mAChR) presynaptically located (autoreceptors).

Methods: Stereotaxic lesion of n. basalis magnocellularis was induced by 25 nmol Ibotenic acid injection in the right brain hemisphere of adult, male, Wistar rats. The contralateral hemisphere served as control. Antagonist (quinuclidinyl-benzilate) and agonist (carbachol) specific binding to mAChR receptors at equilibrium was studied 7 days post-lesion on a P2 fraction of brain cortex homogenate. Displacement of antagonist binding by carbachol was analyzed by "one-point" and "two-point" model fits.

Results: Muscarinic receptors on the control hemisphere show no sign of lesion related changes as compared to data for intact rat brain: Bmax = 0.896 pmol/mg protein and Kd = 0.25 nM. In the lesioned hemisphere a -10.3% loss of antagonist binding (not statistically significant) was observed, with an increase in receptor affinity. Heterogeneity of agonist binding was found; receptor subtype analysis showed that the proportion M2/M1 was unchanged but an increase in carbachol (M2 selective affinity) did appeared.

Conclusions: We found no evidence of a selective presynaptic localization of muscarinic receptor sub-types on terminals of the cholinergic ascending pathway to the neocortex. A receptor loss related to the intensity of the neurotoxic lesion is suggested as well as the presence of regulative mechanisms (hypersensitivity) for receptors.

We have analyzed, with immunohistochemical staining techniques 26 meningiomas of CNS. Vimentin intermediate filaments was present in all cases in the cytoplasm of tumoral cells. Single epithelium cytokeratin was positive in only 19% cases, same that was obtained with S-100 protein. Whereas 69% of cases expressed epithelial membrane antigen. No case was stained positively with Actin, Desmin and GFAP. The results obtained for others authors are analyzed.

70 patients who had suffered an acute stroke (52 ischaemic and 18 haemorrhagic) were studied with CT and MR, performing both techniques during the first week of disease and correlating the findings with the clinical data. MR proved superior in the detection of ischaemic infarcts, specially those in the posterior territory and with a small size; it was also superior to CT in the detection of leukoaraiosis and the demonstration of vascular obstructions. CT failed to detect a small brain stem haemorrhage secondary to bleeding of a cavernoma, while its performance was similar to that of MR in the remaining cases. In all patients with intracerebral haemorrhages, including two who were examined on the first day, an area of increased density was evidenced in the T1 sequences. It is concluded that CT, due to its greater availability and easiness of performance, must be maintained as first choice in acute stroke in order to differentiate haemorrhage from ischaemia, while MR may provide additional information in selected cases.

Neuroleptic malignant syndrome (NMS) is an adverse reaction of an idiosyncratic nature to drugs having antidopaminergic activity. Pathogenesis is largely disputed. An NMS case is presented which was triggered by flupentixol and was associated with severe hyponatremia (116 mmol/l upon admission). Both clinically and analytically, the hyponatraemia fulfills criteria to be considered secondary to an inappropriate secretion of antidiuretic hormone (SIADH). Other possible causes of hyponatraemia were ruled out. After early treatment with dopaminergic agonists and water restriction, both conditions improved in parallel. The different pathogenetic possibilities which may explain the temporal coexistence of both syndromes in the same patient are discussed. The association of these two conditions is in favour of a probable central pathogenetic cause for NMS. On the other hand, it is suggested that hyponatraemia may mask the diagnosis of NMS.