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J Antonopoulos

Publications and source records attributed to J Antonopoulos.

26 records · Page 2Linked to original sources
PubMed1987

Retinal projections in the hedgehog (Erinaceus europaeus). An autoradiographic and horseradish peroxidase study.

The retinal projections of the hedgehog were studied using tritiated leucine and horseradish peroxidase as orthograde tracers. In both series of experiments labeling was seen bilaterally in the suprachiasmatic nucleus, the dorsal and the ventral lateral geniculate nucleus, the superior colliculus, and the pretectal area and contralaterally in the terminal nuclei (dorsal, lateral and medial) of the accessory optic system. A retino-intergeniculate leaflet projection is described for the first time in this species, and its significance is discussed.

Animals↗
PubMed1986

Somatostatinlike immunoreactive neurons in the hedgehog (Erinaceus europaeus) and the sheep (Ovis aries) central nervous system.

The morphology and distribution of somatostatinlike immunoreactive perikarya in the central nervous system of the hedgehog and sheep have been studied by means of the peroxidase-antiperoxidase immunohistochemical method. Intracerebroventricular colchicine infusion not only enhanced the immunostaining but also revealed new immunoreactive cell bodies. In both hedgehog and sheep immunoreactive neurons of various forms, ranging from 12 to 28 microns in diameter, were observed in a number of homologous brain structures. However, some species-related differences were noticed. Thus, somatostatinlike immunoreactive neurons were found only in the hedgehog anterior olfactory nucleus, olfactory tubercle, nucleus accumbens, medial parabrachial nucleus, raphe nuclei of the medulla, and spinal trigeminal nucleus, whereas some somatostatin-positive neurons were observed in the locus coeruleus and the pontine reticular formation of the sheep only. Mapping of peptides in species like sheep and hedgehog, with basically different orientations of living behaviour, may contribute in strengthening or extending our views concerning the role of peptides in the central nervous system of mammals.

Amygdala↗
PubMed1986

Neurotensinlike immunoreactive neurons in the hedgehog (Erinaceus europaeus) and the sheep (Ovis aries) central nervous system.

Neurotensin-containing neurons in the hedgehog and sheep central nervous system were studied immunohistochemically. In both species, mapping of neurotensin neurons was achieved only after pretreatment with colchicine injected intracerebroventricularly 2 days prior to perfusion. Bipolar or multipolar neurotensin neurons, 10-30 micron in diameter, were observed in the following regions of the central nervous system of both species: medial amygdaloid nucleus, lateral septal nucleus, interstitial nucleus of the stria terminals, caudate nucleus, preoptic area, and hypothalamus. On the contrary, while immunoreactive neurons were found in the central amygdaloid nucleus, nucleus accumbens, nucleus of the diagonal band, subthalamus, superior central nucleus, dorsal raphe nucleus, central gray substance of the pons, and dorsal horn of the spinal cord of the hedgehog, respective regions of the sheep appeared to be devoid of immunoreactive perikarya. Also, in some regions, namely the hippocampal formation, the central gray substance of the midbrain, the locus coeruleus, and the nucleus of the solitary tract, neurotensin neurons were found exclusively in the latter species. The existence of these differences in the distribution pattern of neurotensin-immunoreactive neurons between the two species as well as between them and others already examined is briefly discussed.

Amygdala↗
PubMed1986

Thalamic projections to the posterior sylvian and posterior ectosylvian gyri of the sheep brain, revealed with the retrograde transport of horseradish peroxidase.

The auditory area of the sheep cerebral cortex was studied on the basis of its afferents from the medial geniculate nucleus, traced with the horseradish peroxidase retrograde transport method. The results show that the medial geniculate nucleus projects only to the anterior parts of the posterior ectosylvian gyrus and the posterior sylvian gyrus. A small area of the posterior ectosylvian gyrus receives afferents exclusively from the ventral part of the medial geniculate nucleus, while the anterior part of the posterior sylvian gyrus receives also afferents from the posterior nucleus of the thalamus and the pulvinar. In addition, it was found that the medial part of the medial geniculate nucleus projects in a sparse way to the auditory cortex. The middle part of the posterior ectosylvian gyrus receives afferents from the posterior nucleus of the thalamus, the suprageniculate nucleus and the pulvinar, while the posterior part of the posterior ectosylvian gyrus together with the posteriormost part of the posterior sylvian gyrus receive afferents from the pulvinar. Finally, the area located between the anterior and the posteriormost part of the posterior sylvian gyrus receives afferents from both the posterior nucleus of the thalamus and the pulvinar.

Animals↗
PubMed1985

The coexistence of oxytocin and corticotropin-releasing factor in the hypothalamus: an immunocytochemical study in the rat, sheep and hedgehog.

The unlabeled antibody enzyme method has been applied on adjacent sections in order to investigate coexistence of oxytocin (OXY) and corticotropin-releasing factor (CRF) within individual neurons of the hypothalamic paraventricular nucleus of the colchicine-treated rat, sheep and hedgehog. Our results show that, although OXY and CRF immunoreactivities are both expressed by a number of cells in the rat and the sheep paraventricular nucleus, this is not the case for the hedgehog.

Animals↗
PubMed1985

Thalamic projections to motor, prefrontal, and somatosensory cortex in the sheep studied by means of the horseradish peroxidase retrograde transport method.

In this study the motor, prefrontal, and somatosensory areas of the sheep cerebral cortex were defined on the basis of their thalamic afferents traced with the horseradish peroxidase method. The motor area (areas 4 and 6) occupies the cruciate gyrus. It receives a substantial projection from the thalamic nuclei ventralis anterior, ventralis lateralis, medialis dorsalis, and centralis lateralis and a smaller one from the nuclei ventralis medialis, centralis medialis, paracentralis, lateralis dorsalis, lateralis posterior, centromedianus, parafascicularis, suprageniculatus, ventralis posterolateralis, and the midline nuclei. Area 4 receives afferents mainly from the nuclei ventralis anterior, ventralis lateralis, medialis dorsalis, and lateralis posterior, whereas area 6 receives afferents mainly from the nuclei ventralis anterior, medialis dorsalis, and lateralis posterior and fewer afferents from the nucleus ventralis medialis. The prefrontal area occupies the gyrus proreus and receives numerous afferents from the nucleus medialis dorsalis and fewer from the nuclei lateralis posterior and ventralis medialis. The area extending between the lateral fissure, the coronal sulcus, the presylvian sulcus, and the rostral branch of the lateral fissure is connected mainly with sensory thalamic nuclei. Thalamic afferents were found to emanate from the nuclei ventralis posteromedialis (its parvicellular part included), ventralis posterolateralis, ventralis medialis, paracentralis, lateralis posterior, medialis dorsalis, centromedianus, suprageniculatus, paraventricularis, the substantia nigra, and the ventral part of the lateral geniculate nucleus. The first somatosensory area (Johnson et al., '74, J. Comp. Neurol. 158:81-108) was found to extend between the coronal, the diagonal, and the anterior suprasylvian sulci and to receive afferents almost exclusively from the nucleus ventralis posteromedialis.

Animals↗
PubMedDate not supplied

Distribution of neuropeptides in the infundibular nucleus of the sheep.

The distribution of neurons exhibiting somatostatin (SRIF)-, neuropeptide Y (NPY)-, beta-endorphin- and neurotensin (NT)-like immunoreactivity within the infundibular nucleus (NI) of the sheep, and the extent of coexistence of the above peptides within individual neurons of the NI were investigated with immunocytochemical techniques. Our results show that the above neurochemical types of neurons exhibit specific and largely non-overlapping patterns of distribution within the NI of the sheep. Furthermore, the coexistence of these peptides within neurons of the NI is very limited, as from all possible permutations checked, only SRIF and NPY were found together in a small number of cells.

Animals↗