PubMed Health⌕ Search

Biomedical subjects

F Bermúdez-Rattoni

Publications and source records attributed to F Bermúdez-Rattoni.

46 records · Page 3Linked to original sources
PubMed1986

Flavor-illness aversions: the role of the amygdala in the acquisition of taste-potentiated odor aversions.

In the present experiments the role of the amygdaloid complex and its specific nuclei were tested in the conditioning of taste potentiated odor aversions. In the first experiment two groups of rats were given either large electrolytic lesions in the amygdala (AMX) or sham operations (SH). Postoperatively, these rats were trained to avoid either a taste, an odor, or a taste-odor compound using LiCl illness. Subsequent tests with odor and taste alone showed that the SH group developed strong taste and odor aversions; however, the AMX group failed to display either an odor or taste aversion. In the second experiment, another four groups of rats received either lesions in the medial and basomedial nuclei (M), central nuclei (C), lateral and basolateral (L), or sham operations (SH). The results from postoperative conditioning showed that all groups had strong taste and odor aversions, except group L which displayed a significant disruption of odor aversion learning. In conclusion, these data indicate that the amygdala is involved in the acquisition of taste, odor and potentiated odor aversions learning. Moreover, it is demonstrated that the lateral and/or basolateral nuclei are particularly involved in the development of potentiated odor aversions learning.

Amygdala↗
PubMed1986

Is cholinergic activity of the striatum involved in the acquisition of positively-motivated behaviors?

Cholinergic activity of the caudate-putamen (CPU) is crucial for the acquisition of aversively-reinforced behaviors (active and passive avoidance). To determine whether this activity is also involved in the acquisition of a positively-rewarded behavior, in the present experimental series the effects of scopolamine applications to the antero-dorsal or postero-dorsal aspects of the striatum on auto-shaping were assessed. The auto-shaping procedure that was used allowed rats to learn to bar press at their own rate. It was found that scopolamine injection into either region of the CPU produced a marked retardation in the acquisition of the conditioned behavior. These results indicate that cholinergic activity of the striatum is critically involved in the early phases of positively-reinforced learning.

Animals↗
PubMedDate not supplied

Nerve growth factor with insular cortical grafts induces recovery of learning and reestablishes graft choline acetyltransferase activity.

Rats showing disrupted taste aversion due to insular cortex (IC)-lesions received either IC-grafts with NGF, grafts without NGF, or NGF alone. An additional group served as lesioned controls. Only those animals that received IC-grafts with NGF recovered the ability to learn the conditioned taste aversion task, at 15 days post-graft. Choline acetyltransferase (ChAT) activity in the IC-grafts with, but not without NGF, was similar to the IC activity of unoperated controls. In contrast, glutamate decarboxylase activity was similar in all the groups. These findings suggest that IC-grafts associated with NGF induce recovery of learning abilities in IC-lesioned rats, which correlates with reestablishment of ChAT activity in the grafts at 15 days post-implantation.

Animals↗
PubMedDate not supplied

Adrenal medullary grafts restore olfactory deficits and catecholamine levels of 6-OHDA amygdala lesioned animals.

Aside from motor and cognitive deficits, Parkinson patients also manifest a little-studied olfactory deficit. Since in Parkinson's disease there is a dopamine depletion of the amygdala due to mesocorticolimbic system degeneration, we decided to test olfactory and taste performance of 6-OHDA amygdala lesioned rats, as well as the possible restoration of either function with adrenal medullary transplants. Two 6-OHDA lesioned groups and one control group were tested in the potentiation of odor by taste aversion paradigm. On taste aversion none of the groups showed any impairment. In contrast, the 6-OHDA lesioned rats showed a marked impairment in olfactory aversion. At this point, one of the lesioned groups received a bilateral adrenal medullary graft within the lesioned area. After two months, all groups were submitted again to the behavioral paradigm. Taste remained unaffected, but the lesioned only group did not recover either olfactory aversion or normal catecholamine levels. The grafted group, on the other hand, restored olfactory aversion and catecholamine levels. It can be concluded from this study that catecholamine depletion of the amygdala is sufficient to produce a selective olfactory deficit, not accompanied by taste impairments, and that such a deficit can be reversed by adrenal medullary transplants, which in turn restore catecholamine levels.

Adrenal Medulla↗
PubMedDate not supplied

Graft-induced recovery of inhibitory avoidance conditioning in striatal lesioned rats is related to choline acetyltransferase activity.

Four groups of male Wistar rats showing disrupted inhibitory avoidance conditioning due to striatal lesions received either striatal or ventral mesencephalic brain grafts. Two additional non-lesioned groups were used as controls. Half of the groups was retrained in an inhibitory avoidance task at fifteen days postgraft and the other half at sixty days postgraft. Those animals receiving striatal grafts significantly improved their ability to acquire the inhibitory avoidance task at fifteen and sixty days postgraft, as opposed to those receiving mesencephalic grafts, which did not show behavioral recovery. Choline acetyltransferase and glutamate decarboxylase activities, as well as dopamine content, were measured in the grafted tissue. Striatal grafts showed levels of choline acetyltransferase activity similar to the control group. Moreover, a positive correlation was found between the choline acetyltransferase activity and the behavioral recovery. In contrast, both glutamate decarboxylase activity and dopamine levels were significantly lower in striatal and in mesencephalic grafts, as compared to the controls. These results show that striatal but not mesencephalic grafts can promote the restoration of the ability to acquire an inhibitory avoidance task even at early stages (15 days) of the development of the grafts. The results also suggest that acetylcholine plays an important role in behavioral recovery.

Animals↗
PubMedDate not supplied

Morphometric study of fetal brain transplants in the insular cortex and NGF effects on neuronal and glial development.

Homotopic grafts supplemented with nerve growth factor (NGF) speed the recovery from learning deficits observed following electrolytic lesions of the insular cortex in rats. NGF also reduces the time in which the activity of choline acetyltransferase (ChAT) is first detected inside the graft by histochemical techniques. It is not known whether this behavioral and biochemical recovery correlates with an advanced maturation of the cellular elements within the graft, presumably induced by NGF. To investigate the degree of maturation of neurons, glial cells and blood vessels in NGF-supplemented grafts, adult rats were lesioned electrolytically in the insular cortex, and homotopic embryonic grafts (E16) with or without NGF supplementation were transplanted into the lesion. Fifteen days post grafting, the rats were perfused and the brains stained using silver impregnation techniques. Our results showed that neuronal maturation, as evaluated through several morphometric parameters, was advanced in NGF-supplemented grafts when compared with other experimental groups. Furthermore, grafts supplemented with NGF also showed significant increases in the number of neurons, oligodendrocytes, astrocytes and blood vessels. These observations indicated that the addition of NGF to insular cortex grafts promoted the maturation of neuronal and glial elements within the graft. They also support the possibility that the advanced morphological maturation of insular cortex grafts supplemented with NGF underlies the accelerated functional and biochemical recovery of animals with lesions of the insular cortex.

Animals↗
PubMedDate not supplied

[Behavior-immunity relationship: the role of cytokines].

There are several phenomena in which the immune and the central nervous systems regulate each other. However, their mechanisms are poorly understood. Since cytokines have a central role in the regulation of the immune response, this review describes their participation in two forms of neuro-immune communication, immunomodulation by psychological stress and behavioral conditioning of immune response. The role of cytokines in the endocrine and behavioral effects of acute phase, where cytokines have an effect in functions of the central nervous system, is also reviewed. The effects of psychological stress are described as both immunosuppressing and immunoenhancing. Among them, a relevant immunosuppressing one is the reduction of IL-1, IL-2, and IFN-gamma levels. In contrast, some of the pro-inflammatory effects of stress are mediated by an increase in the levels of IL-6, IL-1, and TNF mediated by the neurotransmitter Substance P. A possible role for IL-1 and IFN-beta as possible messengers in immune regulation by behavioral conditioning is proposed. Pro-inflammatory cytokines in turn can activate the hypothalamus-pituitary-adrenal axis and induce sickness behavior during the acute phase response, during which the parasympathetic nervous system serves as pathway for their detection by the central nervous system. An account is given about recent findings on the regulation of cytokine expression by neurotransmitters from the sympathetic nervous system (epinephrine and norepinephrine), a key piece in all these mechanisms of brain-immune communication. Possible mechanisms and pathways of communication between the brain and the immune system, as well as the possible participation of other cytokines are discussed.

Animals↗
PubMedDate not supplied

[Memory-linked morphological changes].

INTRODUCTION: It has been suggested that storing information in the brain takes place by means of changes in synaptic communication efficiency, which is known as neuronal plasticity. Plastic events include changes in the function, structure, distribution and number of synapses, and it has been suggested that these plastic events could be related to learning and memory. DEVELOPMENT: In this work we will review some studies that report structural changes in which experience and learning intervene. In particular, structural changes have been observed in a region of the brain called the hippocampus, which plays a crucial role in the learning and memory of spatial tasks. It has been claimed that the appearance of new synapses after learning a spatial task is linked to the formation of long-term memory and that the functioning of NMDA-type glutamate receptors is needed for both learning and the formation of new synapses to take place. CONCLUSIONS: Understanding the cellular mechanisms involved in the formation of memory is of utmost importance to be able to check the memory deficiencies that arise from injuries or as a consequence of old age and neurodegenerative diseases.

Animals↗