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E Mengual

Publications and source records attributed to E Mengual.

At least 19 recordsLinked to original sources
PubMed2001

Barrel pattern formation requires serotonin uptake by thalamocortical afferents, and not vesicular monoamine release.

Thalamocortical neurons innervating the barrel cortex in neonatal rodents transiently store serotonin (5-HT) in synaptic vesicles by expressing the plasma membrane serotonin transporter (5-HTT) and the vesicular monoamine transporter (VMAT2). 5-HTT knock-out (ko) mice reveal a nearly complete absence of 5-HT in the cerebral cortex by immunohistochemistry, and of barrels, both at P7 and adulthood. Quantitative electron microscopy reveals that 5-HTT ko affects neither the density of synapses nor the length of synaptic contacts in layer IV. VMAT2 ko mice, completely lacking activity-dependent vesicular release of monoamines including 5-HT, also show a complete lack of 5-HT in the cortex but display largely normal barrel fields, despite sometimes markedly reduced postnatal growth. Transient 5-HTT expression is thus required for barrel pattern formation, whereas activity-dependent vesicular 5-HT release is not.

Aging↗
PubMed2001

Thalamic distribution of zinc-rich terminal fields and neurons of origin in the rat.

Several cortico-cortical and limbic-related circuits are enriched in zinc, which is considered as an important modulator of glutamatergic transmission. While heavy metals have been detected in the thalamus, the specific presence of zinc has not been examined in this region. We have used two highly sensitive variations of the Timm method to study the zinc-rich innervation in the rat thalamus, which was compared to the distribution of acetylcholinesterase activity. The origin of some of these zinc-rich projections was also investigated by means of retrograde transport after intracerebral infusions of sodium selenium (Na2SeO3). The overall zinc staining in the thalamus was much lower than in the neocortex, striatum or basal forebrain; however, densely stained terminal fields were observed in the dorsal tip of the reticular thalamic nucleus, the anterodorsal and lateral dorsal thalamic nuclei and the zona incerta. In addition, moderately stained zinc-rich terminal fields were found in the rostral intralaminar nuclei, nucleus reuniens and lateral habenula. Intracerebral infusions of Na2SeO3 in the lateral dorsal nucleus resulted in retrogradely labeled neurons that were located in the postsubiculum, and also in the pre- and parasubiculum. These results are the first to establish the existence of a zinc-rich subicular-thalamic projection. Similar infusions in either the intralaminar nuclei or the zona incerta resulted in labeling of neurons in several brainstem structures related to the reticular formation. Our results provide morphological evidence for zinc modulation of glutamatergic inputs to highly selective thalamic nuclei, arising differentially from either cortical limbic areas or from brainstem ascending activation systems.

Acetylcholinesterase↗
PubMed2000

Considerations on the thalamostriatal system with some functional implications.

The thalamostriatal projections are largely neglected in current reviews dealing with basal ganglia function. In the past few years, however, several studies have re-evaluated these projections and have postulated their implication in more complex tasks within the basal ganglia organization. In this review, we try to focus on the morphological and functional importance of this system in the basal ganglia of the rat, cat and monkey. Special attention is paid to the thalamus as an important place for interaction between the input and the output systems of the basal ganglia through the thalamostriatal projections. Thus, we stress on the overlapping thalamic territories between the thalamic projection of the output nuclei of the basal ganglia and the thalamostriatal neurons. Our experimental data support the existence of several thalamic feedback circuits within the basal ganglia functional design. Finally, some considerations are provided upon the functional significance of these thalamic feedback circuits in the overall organization of the basal ganglia in health and disease.

Animals↗
PubMed1999

Double retrograde tracer study of the thalamostriatal projections to the cat caudate nucleus.

The distribution of thalamostriatal neurons projecting to the cat caudate nucleus was examined by retrograde fluorescent tracers. Thus, Fast Blue and Diamidino Yellow were concomitantly injected in different rostrocaudal, dorsoventral, or mediolateral sectors of the caudate nucleus. The main findings of this study are as follows: (1) few double-labeled cells were found after two injections in different sectors of the caudate nucleus; (2) double-labeled neurons were more abundant after adjacent injections and they were mainly located in the caudal intralaminar nuclei, in the rhomboid nucleus and in the dorsal mediodorsal nucleus; and (3) there were variations in the spatial organization of the thalamostriatal neurons projecting to various sectors of the caudate nucleus in the different thalamic nuclei known to project to this part of the striatum.

Amidines↗
PubMed1999

Induced endothelial cell loss in phacoemulsification using topical anesthesia plus intracameral lidocaine.

PURPOSE: To determine whether lidocaine 1% injected into the anterior chamber during phacoemulsification damaged the corneal endothelium. SETTING: Ophthalmology Service, University Hospital, San Juan de Alicante, Spain. METHODS: In 19 eyes of 19 patients, small incision phacoemulsification and foldable lens (AcrySof MA60BM) implantation was performed using topical anesthesia supplemented by lidocaine 1% (0.3 mL) in the anterior chamber. All cases were operated by the same surgeon. Specular microscopy was performed before surgery and 1 and 3 months postoperatively. RESULTS: Mean endothelial cell loss was 5.41% +/- 8.50 (SD) at 1 month and 5.93 +/- 8.50% at 3 months. CONCLUSIONS: The endothelial damage was similar to that described by other authors, suggesting that phacoemulsification surgery can be performed successfully using topical anesthesia supplemented by lidocaine 1% in the anterior chamber.

Aged↗
PubMed1999

Thalamic interaction between the input and the output systems of the basal ganglia.

The striatal return through the thalamus is largely neglected in current studies dealing with basal ganglia function, and its role within this circuitry remains obscure. In this contribution the thalamus is regarded as an important place of interaction between the input and the output organization of the basal ganglia. In support of this idea, a brief overview is provided of some of the most recent findings concerning the thalamus in relation to the basal ganglia circuitry. In particular, we have focused on the thalamostriatal projections themselves, on the output of the basal ganglia to the thalamus and also on the overlapping territories between the thalamic projection of the output nuclei and the thalamostriatal neurons. These data support the existence of several thalamic feedback circuits within the basal ganglia neural system. Finally, some considerations are provided upon the functional significance of these thalamic feedback circuits in the overall organization of the basal ganglia.

Animals↗
PubMed1998

Overlapping territories between the thalamostriatal and nigrothalamic projections in cats.

Fluorescent tracers were injected into different regions of the caudate nucleus and HRP-WGA in the substantia nigra of the cat in order to analyse the thalamic distribution of retrogradely labelled thalamostriatal neurones and anterogradely labelled nigrothalamic terminals within the thalamus. Overlapping thalamic territories between the thalamostriatal neurones projecting to areas of the caudate nucleus and the nigrothalamic connections were observed in the rostral nuclei of the central thalamic group (ventral anterior nucleus, ventral anterior-ventral lateral complex and ventral medial nucleus) and, more restricted, in the rostral (rhomboid, paracentral, ventral lateral, dorsal mediodorsal nuclei) and caudal intralaminar nuclei (centromedian-parafascicular complex). This study provides evidence of the existence of thalamic areas in which the input and output of the basal ganglia converge.

Animals↗
PubMed1998

Overlapping territories between the thalamostriatal and nigrothalamic projections in cats.

Fluorescent tracers were injected into different regions of the caudate nucleus and HRP-WGA in the substantia nigra of the cat in order to analyse the thalamic distribution of retrogradely labelled thalamostriatal neurones and anterogradely labelled nigrothalamic terminals within the thalamus. Overlapping thalamic territories between the thalamostriatal neurones projecting to areas of the caudate nucleus and the nigrothalamic connections were observed in the rostral nuclei of the central thalamic group (ventral anterior nucleus, ventral anterior-ventral lateral complex and ventral medial nucleus) and, more restricted, in the rostral (rhomboid, paracentral, ventral lateral, dorsal mediodorsal nuclei) and caudal intralaminar nuclei (centromedian-parafascicular complex). This study provides evidence of the existence of thalamic areas in which the input and output of the basal ganglia converge.

Animals↗
PubMed1998

Re-examination of topographic distribution of thalamic neurons projecting to the caudate nucleus. A retrograde labeling study in the cat.

The distribution of thalamic neurons projecting directly to the caudate nucleus (CN) was examined using the retrograde labeling method. Horseradish peroxidase conjugated with wheat germ agglutinin (HRP-WGA) or a fluorescent tracer (either Fast Blue (FB) or Diamidino Yellow (DY)) was injected into various parts of the CN. The main findings were as follows: (1) labeled neurons were distributed most densely in the intralaminar nuclei, midline thalamic nuclei and centre median-parafascicular complex, and less densely in the ventroanterior (VA), ventrolateral (VL) and ventromedial (VM) nuclei. (2) After injections into the rostral parts of the CN, a moderate number of retrogradely labeled neuronal cell bodies was observed in VA, VL and VM. However, only very few, if any, labeled neurons were found in these nuclei after injections into the caudal parts of the CN. (3) After injections into the most dorsolateral parts of the CN, labeled neurons were seen in the lateralmost part of the VA and VL. (4) Many retrogradely labeled neurons were consistently found in the lateral wing of the rhomboid nucleus after injections into the CN. (5) No clear topography was detected in the arrangement of labeled neurons in the rhomboid, dorsal mediodorsal, centrolateral or paracentral nuclei. (6) After injections into the rostral parts of the CN, the most prominent labeling was observed in the ventral part of the centre médian-parafascicular complex.

Amidines↗
PubMed1998

Metallic fragment deposits during phacoemulsification.

PURPOSE: To describe the nature and origin of foreign metallic intraocular bodies appearing after phacoemulsification. SETTING: Department of Ophthalmology, University Hospital of San Juan, Alicante, Spain. METHODS: Two metallic particles, 1 extracted during surgery and the other from a patient in whom surgery had been performed, were studied by scanning electronic microscopy and X-ray dispersive energy spectroscopy. Also evaluated were all metallic elements used in phacoemulsification including phaco tips, Sinskey hooks, and handpieces. A morphologic analysis at various magnifications was performed and the composition of the elements studied. RESULTS: Scanning electronic microscopy showed irregularities of the phaco tip and Sinskey hook after their use. Spectrographic analysis found that the phaco tip was mainly aluminum and titanium; the Sinskey hook, iron, chromium, cobalt, and nickel; the handpiece, iron, chromium, and nickel; and the 2 metallic particles, iron, chromium, and nickel, the same as the handpiece. CONCLUSION: The metallic particles extracted corresponded to those of the phaco handpiece. Vibration during prolonged use of the phacoemulsifier probably caused these particles to chip off the handpiece.

Alloys↗
PubMed1998

Clinical results of AcrySof intraocular lens implantation.

PURPOSE: To analyze the clinical results of AcrySof intraocular lens (IOL) implantation. SETTING: San Juan University Hospital, Alicante, Spain. METHODS: This retrospective study comprised 100 patients with cataract 81 without previous eye pathology and 19 with previous eye pathology (i.e., diabetes, traumatic cataract, central corneal leukoma, glaucoma). Phacoemulsification technique depended on the type of cataract. Mean follow-up was 9 months. RESULTS: Best corrected visual acuity was 20/40 or better in 11.52% of patients with preoperative eye pathology and in 100% of those without pathology. CONCLUSION: Implantation of AcrySof IOLs did not result in complications or adverse reactions in our series, indicating that its use is safe in small incision cataract surgery.

Acrylates↗
PubMed1996

Immunohistochemical distribution and electron microscopic subcellular localization of the proteasome in the rat CNS.

The proteasome multicatalytic proteinase (MCP) is a 20S complex that plays a major role in nonlysosomal pathways of intracellular protein degradation. A polyclonal antibody against rat liver MCP was used to investigate the distribution of MCP in the CNS of the rat and its subcellular localization within the neurons. As expected, MCP immunoreactivity (MCP-IR) was distributed ubiquitously in the rat CNS but not homogeneously. The most intensely stained neurons were the pyramidal cortical neurons of layer 5 and the motor neurons of the ventral horn in the spinal cord, which show an intense nuclear and cytoplasmatic MCP-IR and clearly stained processes. Additionally, some populations of large neurons in the mesencephalon and brainstem also displayed a moderate MCP-IR in their perikarya. The vast majority of neurons in the remaining structures did not show a strong cytoplasmatic MCP-IR, but their nuclei displayed an intense MCP-IR. The subcellular localization also was studied by immunoelectron microscopy. MCP-IR was intense in the neuronal nuclei, and significant staining also was found in the cytoplasm, dendritic, and axonic processes (including some myelinated axons) and in synaptic boutons, as illustrated in the cerebellar cortex. The distribution of MCP in the rat CNS and its subcellular localization are discussed in relation to (1) the distribution of calpain, the other major nonlysosomal cellular protease, and (2) the possible role of MCP in the degradation of regulatory proteins and key transcription factors that are essential in many neuronal responses.

Animals↗
PubMed1995

Heterogeneous and compartmental distribution of zinc in the striatum and globus pallidus of the rat.

The distribution of vesicular or chelatable zinc was analysed in the dorsal and ventral subdivisions of the striatum and globus pallidus of the rat with Danscher's selenium method. Acetylcholinesterase and Calbindin-D28k were used as striatal and pallidal markers in order to analyse the possible compartmentalization of the distribution of zinc in the striatum and globus pallidus. The main findings of this study are the following: (1) The distribution of vesicular zinc in the dorsal striatum was heterogeneous. A peripheral rim of tissue heavily stained for zinc was detected in the medial, dorsal and lateral striatal areas, along most of the rostrocaudal extent of the striatum. addition, patch-like zones intensely stained for zinc were prominent in the rostral half of the caudate-putamen complex. (2) In some regions of the rostral half of the caudate-putamen complex, the staining for zinc appeared to follow the well-known striatal patches (striosomes)/matrix organization. However, in other regions of the rostral half of the striatum such a relation was not detected. (3) The ventral striatum also showed a heterogeneous staining for zinc. Thus, in the most ventral part of the caudate-putamen complex, both subdivisions of the nucleus accumbens and parts of the olfactory tubercle displayed different patterns of compartmentalized distribution of zinc. In the dorsal half of the shell of the nucleus accumbens, some patches with an intense reaction for zinc seemed to overlap with acetylcholinesterase-poor patches. (4) There was a remarkable absence of staining for zinc in the globus pallidus. This histochemical study illustrates, on the one hand, the high content of vesicular zinc in the dorsal and ventral subdivisions of the striatum, which was distributed following different patterns of chemical compartmentalization, and on the other hand, the absence of vesicular zinc in the globus pallidus of the rat.

Acetylcholinesterase↗
PubMed1994

Immunohistochemical distribution of calbindin D-28k and parvalbumin in the head of the caudate nucleus and substantia nigra of the cat.

The heterogeneous anatomy of both the dorsal striatum at the level of the head of the caudate nucleus and of the substantia nigra of cats was analyzed immunohistochemically using two calcium-binding proteins, namely, calbindin D-28k and parvalbumin. The striatal histochemical markers nicotinamide-adenine dinucleotide phosphate diaphorase and acetylcholinesterase were revealed in sections adjacent to those used for the immunohistochemical procedure. The distribution of both the calbindin D-28k and the parvalbumin immunoreactivities is heterogeneous in dorsal, ventral, lateral, and medial areas of the head of the caudate nucleus and is in register with the striosome/matrix pattern displayed by the histochemical markers. These calcium-binding proteins preferentially are located in the matrix compartment of the rostral caudate nucleus. Moreover, in some areas of the rostral two-thirds of the substantia nigra, calbindin D-28k and parvalbumin immunoreactivities appear to follow a complementary pattern that is quite different from the mesencephalic distribution of these two calcium-binding proteins.

Acetylcholinesterase↗
PubMed1993

Nicotinamide-adenine dinucleotide phosphate diaphorase activity matches acetylcholinesterase-rich patches in the medial thalamic nuclei of the cat.

Patches of high nicotinamide-adenine dinucleotide phosphate diaphorase (NADPH-d) activity were found in the mediodorsal and midline thalamic nuclei of cats. These patches matched acetylcholinesterase (AChE)-rich patches within the medial thalamus, whereas other AChE-rich patches were NADPH-d negative. There were also patches of NADPH-d activity in the lateral habenula, but these did not match the AChE staining. These results suggest that the functional role of discrete thalamic regions may require the joint presence of AChE and NADPH-d enzymatic activities.

Acetylcholinesterase↗
PubMed1993

Local NADPH-diaphorase neurons innervate pial arteries and lie close or project to intracerebral blood vessels: a possible role for nitric oxide in the regulation of cerebral blood flow.

Electrical stimulation of perivascular nerves induced a relaxation of endothelium-denuded cat pial arteries that was significantly reduced by nitric oxide (NO) synthase inhibition, indicating that NO was involved in the neurogenic relaxation of these vessels. Histochemical staining of the pial arteries for NADPH-diaphorase (NADPH-d), used as a marker for NO synthase, showed positive nerve fibers in the adventitial layer. Interestingly, in some restricted areas stained neuronal cell bodies were also observed. These neurons were scattered or distributed in small groups in a ganglion-like manner, and they sent fibers to the vessel wall. No NADPH-d-positive nerve fibers or cell bodies were detected in forelimb, pulmonary, or coronary arteries. Within the brain parenchyma, blood vessels also showed positive fibers around their walls. These fibers were organized in a branching pattern and presented varicosities. NADPH-d-positive neurons were found in the proximity of the intracerebral vascular profiles, sending processes to the vessels and/or being directly apposed to their wall. The neurovascular contacts were preferentially located close to the interface between the cerebral cortex and white matter. The anatomical relationship between NADPH-d-positive neurons and fibers and the cerebral blood vessels, together with the participation of NO in the neurogenic relaxation of pial arteries, suggests that NO is involved in the regulation of cerebral blood flow.

Animals↗
PubMed1992

[Projections from lamina V of the cerebral cortex to the dorsomedial thalamic nucleus and neighboring nuclei].

The laminar projections from the cerebral cortex to the mediodorsal thalamic nucleus and adjacent thalamic nuclei were studied by means of the horseradish peroxidase (HRP) retrograde axonal transport method. A possible correlation was found between the connectivity arising from layer V of the cerebral cortex, and the rich-acetylcholinesterase (AChE) regions within the subcortical structures under study. This suggests the possibility that layer V of the cerebral cortex in Alzheimer's disease is initially affected and subsequently those rich-AChE subcortical regions with which it is connected.

Acetylcholinesterase↗