RESUMEN
Ependymomas are relatively rare neuroglial tumours that derive from ependymal cells, lining the ventricles of the brain and the central canal of the spinal cord. They occur particularly in dogs, while reports in goats are extremely scarce. A 15-year-old female dwarf goat was found in lateral recumbency, developed opisthotonus and was killed humanely. Necropsy revealed a well-demarcated, non-encapsulated mass in the diencephalon at the level of the interthalamic adhesion. Histologically, the neoplasm showed highly cellular sheets of tumour cells with occasional perivascular pseudorosettes and true rosettes. Immunohistochemistry revealed an extensive and perivascularly accentuated expression of S100 protein and glial fibrillary acidic protein, while vimentin expression was observed to a minor extent. Tumour cells were negative for cytokeratin and CNPase. Ultrastructurally, intercellular junctions were present, but cilia and blepharoblasts were lacking. The presented findings are consistent with a cellular subtype of an ependymoma. Ependymomas should be regarded as a rare cause of central nervous signs in goats.
Asunto(s)
Neoplasias Encefálicas/veterinaria , Diencéfalo/patología , Ependimoma/veterinaria , Enfermedades de las Cabras/patología , Animales , Autopsia/veterinaria , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/ultraestructura , Diencéfalo/ultraestructura , Ependimoma/patología , Ependimoma/ultraestructura , Eutanasia Animal , Femenino , Cabras , Inmunohistoquímica/veterinaria , Microscopía Electrónica de Transmisión/veterinariaRESUMEN
We have studied the influence of bilateral carotid ischemia-reperfusion on the indices of the functional and morphological condition of the vascular endothelium of the brain hypothalamolimbic complex. It has been established that a decrease of the density of endothelial location in an early ischemic-reperfusion period in the control rats has a relative characterstipulated by edema of cells whereas on the 12-th day of observation an increase of the absolute density of cells takes place. During both periods of observation there is an increased content of the tjtal RNA in the capillary endotheliocytes of all the structures. An early reaction of the morpho-functional states of endotheliocytes to ischemic-reperfusion is absent in animal with diabetes mellitus, exept the vessels of the ventromedial hypothalamus while a late one is restricted by a growth content in RNA cells.
Asunto(s)
Diabetes Mellitus Experimental/patología , Diencéfalo/irrigación sanguínea , Endotelio Vascular/ultraestructura , Daño por Reperfusión/patología , Animales , Glucemia/metabolismo , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/metabolismo , Diencéfalo/ultraestructura , Masculino , Microscopía Electrónica , Ratas , Daño por Reperfusión/complicaciones , Daño por Reperfusión/metabolismoRESUMEN
This study investigated the nuclear organization of four immunohistochemically identifiable neural systems (cholinergic, catecholaminergic, serotonergic and orexinergic) within the brain of the African pygmy mouse (Mus minutoides). The African pygmy mice studied had a brain mass of around 275 mg, making these the smallest rodent brains to date in which these neural systems have been investigated. In contrast to the assumption that in this small brain there would be fewer subdivisions of these neural systems, we found that all nuclei generally observed for these systems in other rodent brains were also present in the brain of the African pygmy mouse. As with other rodents previously studied in the subfamily Murinae, we observed the presence of cortical cholinergic neurons and a compactly organized locus coeruleus. These two features of these systems have not been observed in the non-Murinae rodents studied to date. Thus, the African pygmy mouse displays what might be considered a typical Murinae brain organization, and despite its small size, the brain does not appear to be any less complexly organized than other rodent brains, even those that are over 100 times larger such as the Cape porcupine brain. The results are consistent with the notion that changes in brain size do not affect the evolution of nuclear organization of complex neural systems. Thus, species belonging to the same order generally have the same number and complement of the subdivisions, or nuclei, of specific neural systems despite differences in brain size, phenotype or time since evolutionary divergence.
Asunto(s)
Acetilcolina/fisiología , Encéfalo/anatomía & histología , Encéfalo/fisiología , Catecolaminas/fisiología , Núcleo Celular/fisiología , Péptidos y Proteínas de Señalización Intracelular/fisiología , Ratones/fisiología , Neuropéptidos/fisiología , Serotonina/fisiología , Animales , Ganglios Basales/fisiología , Ganglios Basales/ultraestructura , Encéfalo/ultraestructura , Núcleo Celular/ultraestructura , Corteza Cerebral/fisiología , Corteza Cerebral/ultraestructura , Cuerpo Estriado/fisiología , Cuerpo Estriado/ultraestructura , Diencéfalo/fisiología , Diencéfalo/ultraestructura , Inmunohistoquímica , Masculino , Bulbo Raquídeo/fisiología , Bulbo Raquídeo/ultraestructura , Mesencéfalo/fisiología , Mesencéfalo/ultraestructura , Orexinas , Rombencéfalo/fisiología , Rombencéfalo/ultraestructuraRESUMEN
Zona incerta in dog diencephalon was studied by the methods of Nissl and Kluver-Barrera. As a result of this study, 5 individual sectors were identified on the basis of the analysis of fiber Organization, morphological types of neurons and the density of their distribution. The mapping of zona incerta was performed, and the borders of the sectors were accurately determined by histochemical demonstration of NADPH-diaphorase-positive neurons.
Asunto(s)
Neuronas , Subtálamo , Animales , Diencéfalo/fisiología , Diencéfalo/ultraestructura , Perros , NADPH Deshidrogenasa/metabolismo , Neuronas/enzimología , Neuronas/fisiología , Neuronas/ultraestructura , Subtálamo/fisiología , Subtálamo/ultraestructuraRESUMEN
Interthalamic adhesion between the medial surfaces of the left and right thalamus is a variable structure and contains the midline thalamic nuclei, which are not much developed in humans. The research has been done on 6 human brains obtained during routine autopsy (age 45 to 65; 4 male and 2 female). Every tenth 10 microm thick frontal section was stained according to Klüver-Barrera method. In all cases the authors found a specific organization of certain groups of neurons within the interthalamic adhesion (IA) in form of circles on frontal sections. These circular groups were present on all sections but only 1-2 in each. The larger mean diameter of these circular arrangements was R = 229.4 microm, and smaller was r = 203.1 microm. These circular groups within the human IA were formed in average by 7.29 neurons. In periventricular region (PVR) of thalamus similar circular groups of neurons also were present in all cases as in IA. These neuronal groups in PVR were of smaller size than in the IA, with larger mean diameter R = 201.4, smaller mean diameter r = 181.2 microm and they contained fewer neurons, 6.69 on average. All three values (both diameters of circular arrangements, and number of neurons forming them) were significantly smaller in PVR (p < .01). Morphological types and sizes of neurons in both investigated structures (IA and PV) were not different. The circular neuronal groups in IA were formed in 61% of fusiform neurons and in PVR in 48% of fusiform neurons. According to their subependymal localization, size and form, these circular groups can represent in vivo correlates of neurospheres.
Asunto(s)
Diencéfalo/ultraestructura , Núcleos Talámicos de la Línea Media/ultraestructura , Conducción Nerviosa/fisiología , Neuronas/ultraestructura , Anciano , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The visual cells in the retinae of the sturgeon were studied by scanning electron microscopy and transmission electron microscopy. Our investigations revealed the presence of rods, two types of single cones, one type of double cone (two nonidentical cone components adhered together), and one type of twin cone (two identical cone components adhered together). In some of the cones, large glycogen bodies were present in the inner segments and all cones contained oil droplets. Such cone morphology was very similar to that described in the retinae of higher vertebrates, for example the chicken. DiI tracing of retinofugal pathways following uniocular injection demonstrated their bilateral localization and extensive termination in the diencephalon and mesencephalon of both sides. Fibers also crossed over from one side to another through commissures, including the posterior commissure. The complexity of the pathway surpassed that of the teleosts and further indicated the evolutionary importance of this fish.
Asunto(s)
Peces/anatomía & histología , Células Fotorreceptoras Retinianas Conos/ultraestructura , Células Fotorreceptoras Retinianas Bastones/ultraestructura , Vías Visuales/cirugía , Animales , Carbocianinas/metabolismo , Diencéfalo/ultraestructura , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Coloración y Etiquetado , Vacuolas/ultraestructuraRESUMEN
Experimental allergic encephalomyelitis (EAE) is an animal model for the human demyelinating disease multiple sclerosis (MS). Increased permeability of the blood-brain barrier (BBB) precedes the development of clinical or pathologic findings in MS and may be induced by perivascular brain mast cells secreting vasoactive and proinflammatory molecules. Brain mast cells were investigated ultrastructurally in acute EAE of the non-human primate common marmoset Callithrix jacchus, which develops a mild neurologic relapsing-remitting course. Control diencephalic samples contained perivascular mast cells with mostly intact electron dense granules. In contrast, EAE samples had marked demyelination and mast cells with numerous altered secretory granules; their electron dense content varied in amount and texture with a "honeycomb" or "target" appearance, but without degranulation. These changes were evident even before the development of any clinical symptoms and suggest that brain mast cells may be involved in EAE, and possibly MS, through a unique process that may involve selective secretion of molecules able to disrupt the BBB.
Asunto(s)
Encéfalo/ultraestructura , Degranulación de la Célula , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Mastocitos/metabolismo , Mastocitos/ultraestructura , Animales , Encéfalo/irrigación sanguínea , Encéfalo/metabolismo , Encéfalo/patología , Callithrix , Gránulos Citoplasmáticos/metabolismo , Gránulos Citoplasmáticos/patología , Gránulos Citoplasmáticos/ultraestructura , Diencéfalo/irrigación sanguínea , Diencéfalo/metabolismo , Diencéfalo/patología , Diencéfalo/ultraestructura , Exocitosis , Humanos , Masculino , Mastocitos/patología , Vaina de Mielina/patología , Vaina de Mielina/ultraestructuraRESUMEN
Gonadal functions are modulated by corticotropin-releasing factor (CRF) in the rat via direct suppression of LH-releasing hormone (LHRH) release. Although there is evidence of direct morphological contacts between the LHRH and CRF-immunoreactive (-IR) structures in the rat hypothalamus, little is known about the morphological base of CRF-influenced LHRH release in man. Thus, we studied the distribution of the CRF-IR and LHRH-IR systems in the human diencephalon and revealed putative CRF-LHRH juxtapositions using double label immunohistochemistry. LHRH-IR cells were present mainly in the infundibular region and the medial preoptic area. CRF-IR neuronal structures were observed in the periventricular area, paraventricular nucleus, infundibular region, and median eminence. CRF-LHRH juxtapositions were found mainly in the infundibulum and median eminence. Few juxtapositions were detected in the medial preoptic area. In these regions, black diaminobenzidine/silver-labeled CRF-IR fibers abutted fusiform brown diaminobenzidine-labeled LHRH neurons, usually forming multiple contacts. Examination of semithin sections of these close associations with the aid of oil immersion revealed no cleft between CRF-IR nerve terminals contacting LHRH-IR structures. These findings suggest that the juxtapositions between the LHRH-IR and CRF-IR neurons may be functional synapses forming the morphological substrate of the CRF-controlled LHRH secretion. Moreover, the wide distribution of CRF-IR elements suggests that CRF controls other diencephalic functions as well.
Asunto(s)
Axones/metabolismo , Hormona Liberadora de Corticotropina/metabolismo , Diencéfalo/citología , Diencéfalo/metabolismo , Hormona Liberadora de Gonadotropina/metabolismo , Neuronas/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Axones/ultraestructura , Diencéfalo/ultraestructura , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Neuronas/citologíaRESUMEN
The present work is an analysis of the afferent projections to the thalamic nucleus rotundus in a lizard, both at the light- and electron-microscopic level, using biotinylated dextran amine (BDA) as a neuroanatomical tracer. This study has confirmed previously reported afferent projections to nucleus rotundus in reptiles and has also identified a number of new cellular aggregates projecting to this dorsal thalamic nucleus. After BDA injections into nucleus rotundus, retrogradely labelled neurons were observed consistently within the following neuronal groups in the midbrain and the diencephalon: (i) the stratum griseum centrale of the optic tectum; (ii) the nucleus subpretectalis in the pretectum; (iii) the nucleus ansa lenticularis posterior, the posterior nucleus of the ventral supraoptic commissure, and the posteroventral nucleus, in the dorsal thalamus and (iv) the lateral suprachiasmatic nucleus and part of the reticular complex in the ventral thalamus. Tectal axons entering nucleus rotundus were fine and varicose and formed exclusively asymmetric synaptic contacts, mainly on small dendritic profiles. Rotundal neurons had symmetric synapses made by large boutons probably of nontectal origin. After comparing our results with those in other reptiles, birds and mammals, we propose that the sauropsidian nucleus rotundus forms part of a visual tectofugal pathway that conveys mesencephalic visual information to the striatum and dorsal ventricular ridge, and is similar to the mammalian colliculo-posterior/intralaminar-striatoamygdaloid pathway, the function of which may be to participate in visually guided behaviour.
Asunto(s)
Biotina/análogos & derivados , Diencéfalo/ultraestructura , Lagartos/anatomía & histología , Mesencéfalo/ultraestructura , Tálamo/ultraestructura , Vías Visuales/ultraestructura , Animales , Dendritas/fisiología , Dendritas/ultraestructura , Dextranos , Diencéfalo/fisiología , Femenino , Lagartos/fisiología , Masculino , Mesencéfalo/fisiología , Microscopía Electrónica , Terminales Presinápticos/fisiología , Terminales Presinápticos/ultraestructura , Desempeño Psicomotor/fisiología , Colículos Superiores/citología , Colículos Superiores/fisiología , Tálamo/fisiología , Vías Visuales/fisiologíaRESUMEN
LHRH release is induced by substance P (SP) in the rat hypothalamus. Recent immunocytochemical studies indicate that SP-immunoreactive axons synapse on LHRH neurons in the diencephalon of the rat, but this phenomenon has not yet been demonstrated in human. Therefore, in the present study we visualized the SP- and LHRH-immunoreactive (IR) elements in the human diencephalon and evaluated the close juxtapositions between them. The distribution of LHRH- and SP-IR sites were investigated in diencephalic sections of six, postmortem human brains by means of double-labeling immunocytochemistry. The LHRH-containing perikarya were located in the diagonal band of Broca, lamina terminalis cinerea, preopticoseptal, medial preoptic, and infundibular areas of the brain. The SP-IR fibers formed a network in the periventricular zone in the infundibular region, median eminence, and corpus striatum. The SP-IR cell bodies were located mainly in the infundibular region, median eminence, basal part of the periventricular area, dorsomedial subdivision of the ventromedial nucleus, and basal perifornical area of the tuberal region. The juxtapositions between LHRH-IR cell bodies and SP-IR varicosities were detected in the infundibular and periventricular regions. In these sites black, silver-intensified, SP-IR fiber varicosities abutted on brown, DAB-labeled, LHRH-IR cell bodies. Similar structures were detected between the SP-IR fibers and SP-IR perikarya. These findings suggest that the juxtapositions between the SP and LHRH systems may be the morphological basis of SP-controlled LHRH release in the human diencephalon. Moreover, the intimate contacts between SP-IR fiber varicosities and SP-IR cell bodies or axons indicate direct control of SP on the diencephalic SP release.
Asunto(s)
Axones/metabolismo , Diencéfalo/metabolismo , Hormona Liberadora de Gonadotropina/metabolismo , Neuronas/metabolismo , Sustancia P/metabolismo , Adulto , Anciano , Cadáver , Diencéfalo/citología , Diencéfalo/ultraestructura , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Distribución TisularRESUMEN
We studied by immunohistochemistry the distribution of differentiation-associated sodium-dependent inorganic phosphate (Pi) cotransporter (DNPI) in the rat forebrain, in comparison with brain-specific cotransporter (BNPI). DNPI-staining was principally seen in axonal synaptic terminals which showed a widespread but discrete pattern of distribution different from that of the BNPI-staining. In the diencephalon, marked DNPI-staining was seen in the dorsal lateral geniculate, medial geniculate, ventral posterolateral, ventral posteromedial, anterior, and reticular thalamic nuclei without the colocalization with BNPI-staining. DNPI-staining showed a strong mosaical pattern and overlapped well the BNPI-staining in the medial habenular nucleus. DNPI-staining was moderate over the hypothalamus and notably localized in neurosecretory terminals containing corticotropin-releasing hormone in the median eminence. In contrast, the BNPI-staining was region-related and strong in the ventromedial and mammillary nuclei. In the telencephalon, laminar DNPI-staining was seen over the neocortex, corresponding to the thalamocortical termination, and also found in the retrosplenial cortex and the striatum, with the highest intensity in the accumbens nucleus shell. The present results suggest that DNPI serves as a dominant Pi transport system in synaptic terminals of diencephalic neurons including thalamocortical and thalamostriatal pathways as well as the hypothalamic neuroendocrine system in the rat forebrain.
Asunto(s)
Proteínas Portadoras/metabolismo , Neuronas/metabolismo , Fosfatos/metabolismo , Prosencéfalo/metabolismo , Sodio/metabolismo , Simportadores , Animales , Especificidad de Anticuerpos , Diencéfalo/metabolismo , Diencéfalo/ultraestructura , Inmunohistoquímica , Masculino , Microscopía Electrónica , Neuronas/ultraestructura , Prosencéfalo/ultraestructura , Ratas , Ratas Sprague-Dawley , Proteínas Cotransportadoras de Sodio-Fosfato , Sinapsis/metabolismo , Sinapsis/ultraestructura , Telencéfalo/metabolismo , Telencéfalo/ultraestructuraRESUMEN
The distribution of luteinizing hormone-releasing hormone (LH-RH)-immunostained cell bodies and fibres was studied in the brainstem and diencephalon of the cat using an indirect immunoperoxidase technique. The brainstem and the thalamus were devoid of immunostained cell bodies, whereas in the hypothalamus immunopositive perikarya were observed in the supraoptic nucleus, the anterior hypothalamus, the preoptic region and in the arcuate nucleus. Our findings also showed that the hypothalamus is richer in immunostained fibres, and that in this region such fibres are more widely distributed than in the thalamus and upper brainstem. No immunopositive fibres were observed in the lower brainstem. Our results point to a more widespread distribution of LH-RH-immunostained perikarya in the cat hypothalamus than that previously reported in the cat; a similar distribution to that found in the rat, and a more restricted distribution than in primates. Additionally, our study shows a more widespread distribution of immunostained fibres in the cat brainstem and diencephalon than that previously described for other mammals. In this context, our results describe for the first time in the mammals central nervous system fibres containing LH-RH located in the stria medullaris of the thalamus, the supramammillary decussation, the laterodorsal and lateroposterior thalamic nuclei, the nucleus reuniens, the supraoptic nucleus, and the optic chiasm. Thus, our findings reveal that LH-RH-immunostained structures are widely distributed in the upper brainstem and in the diencephalon of the cat, suggesting that the peptide may be involved in several physiological functions.
Asunto(s)
Tronco Encefálico/metabolismo , Diencéfalo/metabolismo , Hormona Liberadora de Gonadotropina/metabolismo , Animales , Gatos , Colchicina/farmacología , Diencéfalo/anatomía & histología , Diencéfalo/ultraestructura , Inmunohistoquímica , Inyecciones Intraventriculares , Masculino , Fibras Nerviosas/metabolismoRESUMEN
The habenular complexes represent phylogenetically constant structures in the diencephalon of all vertebrates. Available evidence suggests that this area is engaged in a variety of important biological functions, such as reproductive behaviors, central pain processing, nutrition, sleep-wake cycles, stress responses, and learning. Based on Nissl-stained sections, one medial nucleus and two lateral nuclei (divisions) have been widely accepted in the rat. Cytochemical, hodologic, and functional studies suggest a considerably more complex subnuclear structure. To improve our knowledge of the precise structural composition of the habenular complexes, we have systematically investigated their fine ultrastructure in the rat. Based on the detailed analysis of complete series of large, semithin sections supplemented with electron photomicrographs of selected fields, clear criteria for the delineation of five distinct subnuclei of the medial and ten subnuclei of the lateral habenular complexes were elaborated for the first time. All 15 subnuclei were reconstructed, and their dimensions were determined. A medial and lateral stria medullaris were described. Different roots of the fasciculus retroflexus were differentiated within the medial and lateral habenular complexes. The topographical relationships with respect to the adjacent habenular areas as well as to the neighboring thalamic nuclei were identified and demonstrated. The new understanding of the subnuclear organization of the habenular complexes certainly will facilitate further functional investigations. Whether the newly identified subnuclei finally will be recognized as functionally distinct awaits ongoing immunocytochemical, hodologic, and functional studies.
Asunto(s)
Diencéfalo/ultraestructura , Habénula/ultraestructura , Ratas/anatomía & histología , Animales , Diencéfalo/anatomía & histología , Femenino , Habénula/anatomía & histología , MasculinoRESUMEN
The distribution of calbindin D-28k-immunoreactive fibers and cell bodies in the cat diencephalon has been analyzed by using the avidin-biotin immunoperoxidase technique. The thalamus showed a higher density of immunoreactive cell bodies than the hypothalamus. A high density of both immunoreactive perikarya and fibers was observed in the nuclei pulvinar, geniculatum mediale and laterale, lateralis posterior and dorsalis, habenularis lateralis and medialis, posterior, subparafascicularis, submedius, centralis medialis, medialis dorsalis, ventralis postero-medialis and postero-lateralis, reticularis, centralis lateralis, rhomboidens, paracentralis, ventralis lateralis, anterior and medialis, reuniens, anterior ventralis and medialis, hypothalamus posterior, corpus mamillare, area hypothalamica dorsalis and in the hypothalami ventromedialis. Moreover, a high density of fibers containing calbindin and a moderate/low density of immunoreactive cell bodies was found in the nuclei periventricularis anterior, parataenialis, hypothalamus lateralis, mamillaris lateralis, filiformis, periventricularis hypothalami, hypothalamus anterior and in the suprachiasmaticus.
Asunto(s)
Diencéfalo/química , Proteínas del Tejido Nervioso/análisis , Proteína G de Unión al Calcio S100/análisis , Animales , Calbindinas , Gatos , Diencéfalo/ultraestructura , Técnicas para Inmunoenzimas , Masculino , Fibras Nerviosas/química , Neuronas/química , Proteína G de Unión al Calcio S100/inmunologíaRESUMEN
This study demonstrates that the fetal optic nerve contains a conspicuous population of transient retinopetal axons. Implants of the carbocyanine dye, DiI, were made into the retina or diencephalon of fetal ferrets to label the retinopetal axons retrogradely or anterogradely, respectively, and sections were immunostained for beta-tubulin to label the early differentiating axons in the optic nerve. Dye implants into the optic nerve head, but not the retinal periphery, retrogradely labeled somata in the ventrolateral diencephalon, provided the implants were made before embryonic day (E) 30. When dye implants were made into the ventrolateral diencephalon, these same retinopetal axons were anterogradely labeled, coursing through the optic nerve but never invading the retina. The axons course as 2-5 fascicles from their cells of origin and turn laterally to enter the optic nerve where it joins the future hypothalamus. The retinopetal cells can be retrogradely labeled as early as E20, before optic axons have left the retina. The optic nerve and fiber layer are immunoreactive for beta-tubulin on E24 and thereafter, whereas on E20 and E22, they are immunonegative. Yet at these early embryonic ages, immunopositive fascicles of axons course from the diencephalon into the optic stalk, confirming the precocious nature of the retinopetal projection. Implants of dye made into the future optic nerve head at these very early stages also retrogradely label retinopetal cells in the future chiasmatic region. These cells are distributed primarily on the side ipsilateral to the midline, but a few can be found contralateral to it. Both these, as well as the retinopetal axons arising from the ventrolateral diencephalon, may serve a transient guidance function for later developing optic axons.
Asunto(s)
Axones/fisiología , Diencéfalo/ultraestructura , Hurones/anatomía & histología , Quiasma Óptico/ultraestructura , Nervio Óptico/ultraestructura , Retina/ultraestructura , Vías Aferentes/fisiología , Animales , Hurones/fisiología , Fibras Nerviosas/fisiología , Nervio Óptico/embriología , Factores de TiempoRESUMEN
We have recently reported that streptozocin (STZ)-induced diabetes in rats was associated with i) reduced Ca2+ pumping by rat brain synaptic plasma membrane Ca(2+)-ATPase (PMCA) and ii) a substantial reduction in the partial pressures of halothane and xenon required to prevent movement in response to stimulation (minimum effective dose or MED). MED for both agents correlated well with the degree of hemoglobin glycation and with PMCA activity. We now report that MEDs for isoflurane, enflurane, and desflurane were also substantially reduced in STZ-diabetic rats, compared with placebo-injected controls. In addition, we examined the effect of insulin treatment, begun 2 weeks after induction of diabetes and continued for 3 more weeks, on isoflurane MED and on brain synaptic PMCA and phospholipid-N-methyltransferase I (PLMT I), another enzyme altered by inhalation anesthetics (IA). Partial treatment of diabetes, as indicated by decreased glycated hemoglobin (GHb) compared to untreated diabetic rats, was associated with an isoflurane MED of 1.05 vol%, intermediate between a control mean of 1.57 vol% and an untreated diabetic mean of 0.82 vol% (p < 0.01), with a trend toward normalization of both PMCA and PLMT I activity. We also examined isoflurane MED and PMCA activity in the cerebrum and diencephalon-mesencephalon (D-M) of control and diabetic rats 2 and 12 weeks after induction of diabetes. Isoflurane MED was substantially reduced in diabetic rats from both treatment periods. Cerebral and D-M PMCA activities were each reduced to about 90% of control values 2 weeks after STZ induction. At 12 weeks, cerebral PMCA pumping in SPM from diabetic rats did not differ from control values, but PMCA pumping in SPM from the D-M was reduced to about 85% of control levels. Good correlation (r = 0.89, p < 0.01) was found between isoflurane MED and GHb in all treatment groups. These findings provide further evidence for an important role for PMCA in IA action. They also suggest that anesthetic effects on the calcium pump at specific anatomic sites may be of major importance in producing anesthesia.
Asunto(s)
Anestésicos por Inhalación , Encéfalo/enzimología , ATPasas Transportadoras de Calcio/metabolismo , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/metabolismo , Insulina/farmacología , Fosfolípidos/metabolismo , Sinapsis/enzimología , Animales , Encéfalo/metabolismo , Encéfalo/ultraestructura , Membrana Celular/enzimología , Membrana Celular/metabolismo , Estado de Conciencia/efectos de los fármacos , Estado de Conciencia/fisiología , Diabetes Mellitus Experimental/fisiopatología , Diencéfalo/enzimología , Diencéfalo/metabolismo , Diencéfalo/ultraestructura , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Masculino , Mesencéfalo/enzimología , Mesencéfalo/metabolismo , Mesencéfalo/ultraestructura , Metilación , Ratas , Ratas Sprague-DawleyRESUMEN
The distribution of mRNA encoding neuropeptide Y in cells of the rat pelvic paracervical ganglion was studied by the use of in situ hybridization with a neuropeptide Y oligodeoxynucleotide probe. The specificity of the hybridization signal was assessed on brain sections and the neurons expressing neuropeptide Y mRNA were actually found in several discrete brain regions already described for containing neuropeptide Y neurons. The present study reports the first demonstration of the presence of neuropeptide Y transcripts in nerve cell bodies and small intensively fluorescent (SIF)-like cells of the pelvic paracervical ganglion, thus providing evidence that neuropeptide Y is synthesized in these two cell types. In addition, a quantitative analysis shows a differential pattern of expression of the peptide mRNA in nerve cell bodies throughout the ganglion.
Asunto(s)
Química Encefálica , Ganglios Simpáticos/química , Neuronas/química , Neuropéptido Y/análisis , Pelvis/inervación , Animales , Secuencia de Bases , Encéfalo/ultraestructura , Diencéfalo/química , Diencéfalo/ultraestructura , Femenino , Técnica del Anticuerpo Fluorescente , Ganglios Simpáticos/ultraestructura , Hibridación in Situ , Datos de Secuencia Molecular , Neuronas/ultraestructura , Neuropéptido Y/genética , ARN Mensajero/análisis , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Telencéfalo/química , Telencéfalo/ultraestructuraRESUMEN
The direct projection from the cerebellar nuclei to the inferior olive is GABAergic. In the present study, we investigated the projection from the cerebellar nuclei to the mesodiencephalic junction which is known to provide an excitatory projection to the inferior olive. The mesodiencephalic junction was studied in cat following anterograde transport of wheatgerm agglutinated horseradish peroxidase from the cerebellar nuclei in combination with: (1) retrograde transport of gold-lectin conjugate from the inferior olive; and (2) postembedding GABA-immunocytochemistry. Light microscopic analysis revealed that overlap of the anterograde and retrograde labeling was especially prominent in the nucleus of Darkschewitsch. Electron microscopic examination of this area showed: (1) that many cerebellar terminals made synaptic contacts with neurons that project to the inferior olive; (2) that virtually all cerebellar terminals were non-GABAergic and displayed an excitatory morphology; and (3) olivary projecting neurons were non-GABAergic. It is concluded that the indirect cerebellar projection to the inferior olive via the nucleus of Darkschewitsch is disynaptic and excitatory.
Asunto(s)
Núcleos Cerebelosos/fisiología , Diencéfalo/fisiología , Vías Nerviosas/fisiología , Núcleo Olivar/fisiología , Sinapsis/fisiología , Animales , Gatos , Diencéfalo/ultraestructura , Oro , Peroxidasa de Rábano Silvestre , Inmunohistoquímica , Lectinas , Microscopía Electrónica , Albúmina Sérica Bovina , Aglutinina del Germen de Trigo-Peroxidasa de Rábano Silvestre Conjugada , Aglutininas del Germen de Trigo , Ácido gamma-Aminobutírico/metabolismoRESUMEN
The medullary pacemaker nucleus of Hypopomus triggers each electric organ discharge (EOD) by a single command pulse. It consists of electrotonically coupled 'pacemaker' cells, which generate the rhythm, and 'relay' cells, which follow the pacemaker cells and excite the spinal motoneurons of the electric organ. The pacemaker cells receive two inputs from the complex of the diencephalic prepacemaker nucleus (PPn), a GABA-ergic inhibition and a glutamatergic excitation. Relay cells, on the other hand, receive two glutamatergic inputs, one from a subnucleus of the PPn, the PPn-C, and a second from the sublemniscal prepacemaker nucleus (SPPn). We have labelled afferents to the pacemaker nucleus by injecting HRP to specific sites of the prepacemaker complex. By using immunogold-labelled antibodies and en-grid staining techniques, we demonstrated GABA and glutamate immunoreactivity in labelled synaptic profiles of ultra-thin sections of the pacemaker nucleus. The two types of synapses were interspersed on the surfaces of pacemaker cells, with GABA-immunoreactive synapses apparently representing the GABA-mediated input of the 'PPn-I', an inhibitory subdivision of the PPn, and glutamate-immunoreactive synapses representing the input of the 'PPn-G', an excitatory subdivision of the PPn. Only glutamate-immunoreactive synapses were found on relay cells.
Asunto(s)
Relojes Biológicos/fisiología , Pez Eléctrico/fisiología , Glutamatos/fisiología , Bulbo Raquídeo/ultraestructura , Ácido gamma-Aminobutírico/fisiología , Animales , Diencéfalo/fisiología , Diencéfalo/ultraestructura , Electrofisiología , Glutamato Descarboxilasa/inmunología , Glutamato Descarboxilasa/metabolismo , Ácido Glutámico , Peroxidasa de Rábano Silvestre , Inmunohistoquímica , Bulbo Raquídeo/enzimología , Bulbo Raquídeo/fisiologíaRESUMEN
The diencephalon is a complex integration centre and intricate relay station of the vertebrate brain. Its development involves the generation of great cellular diversity and neuronal specificity. We report here that it becomes organized in steps, through a stereotyped sequence of neuromeric subdivisions. Diencephalic neuromeres define four cellular domains (D1-D4) that can be followed throughout development, each unit contributing to a well defined part of the adult structural pattern. We propose that the segmental identity of each diencephalic unit is specified by a unique combination of genes, maintained by polyclonal cell lineage restrictions. A comparison of vertebrate and arthropod development suggests that the basic principles that control anterior axial patterning and set up neuronal specificity in the embryonic central nervous system are highly conserved in evolution.