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Biomedical subjects

I Grofová

Publications and source records attributed to I Grofová.

At least 19 recordsLinked to original sources

Mesencephalic and diencephalic afferents to the superior colliculus and periaqueductal gray substance demonstrated by retrograde axonal transport of horseradish peroxidase in the cat.

The mesencephalic and diencephalic afferent connections to the superior colliculus and the central gray substance in the cat were examined by means of the retrograde transport of horseradish peroxidase (HRP). After deep collicular injections numerous labeled cells were consistently found in the parabigeminal nucleus, the mesencephalic reticular formation, substantia nigra pars reticulata, the nucleus of posterior commissure, the pretectal area, zona incerta, and the ventral nucleus of the lateral geniculate body. A smaller number of cells was found in the inferior colluculus, the nucleus of the lateral lemniscus, the central gray substance, nucleus reticularis thalami, the anterior hypothalamic area, and, in some cases, in the contralateral superior colliculus, Forel's field, and the ventromedial hypothalamic nucleus. Only the parabigeminal nucleus and the pretectal area showed labeled cells following injections in the superficial layers of the superior colliculus. In the cats submitted to injections in the central gray substance, labeled cells were consistently found in the contralateral superior colliculus, the mesencephalic reticular formation, substantia nigra parts reticulata, zona incerta and various hypothalamic areas, especially the ventromedial nucleus. In some cases, HRP-positive cells were seen in the nucleus of posterior commissure, the pretectal area, Forel's field, and nucleus reticularis thalami. A large injection in the mediodorsal part of the caudal mesencephalic reticular formation, which included the superior colliculus and the central gray substance, resulted in numerous labeled cells in nucleus reticularis thalami. The findings are discussed with respect to the suggested functional division of the superior colliculus into deep and superficial layers. Furthermore, the possible implications of labeled cells in zona incerta and the reticular thalamic nucleus are briefly discussed.

Afferent Pathways↗

A study on the postulated transoptic regulation of the intraocular pressure.

The possibility that fibers regulating the intraocular pressure originate in the hypothalamus and course in the optic nerve, has been investigated in albino rabbits with different techniques. By means of horseradish perixodase tracing-technique, oculohypothalamic but no hypothalamoocular connections were observed. The water-loading effect on the intraocular pressure was studied after unilateral optic nerve transection. The transection was performed in three experimental groups in the following way: Intracranial transection of one optic nerve, retrobulbar transection of one optic nerve and sham operation on the other side, retrobulbar transection of one optic nerve without sham operation on the other side. In contrast to previous reports, we found no significant side difference in intraocular pressure after water-loading in any of these groups.

Animals↗

An autoradiographic identification of Purkinje axon terminals in the cat.

The Purkinje axon boutons terminating in nuclei fastigii and interpositus in the cat have been identified after injection of 3H leucine into the cerebellar cortex overlying the nuclei. The animals survived from 4-48 h after injection of the isotope. Semithin and ultrathin sections were coated and exposed for 3 and 14 weeks, respectively. The electron micrographs showed labelling over myelinated axons down to a diameter of 0.8 mum, and over boutons. Fifty labelled boutons were used for identification of the shape of their synaptic vesicles. The statistical analysis including the test for skewness showed that 39 boutons (78%) fall in one group. Most of the synaptic vesicles in this group are elliptical (ration from 1:1.1 - 1:1.7). Slightly ovoid vesicles (ration up to 1:1.3) are frequent, but flattened vesicles (ration above 1:1.7) are relatively few in this group of boutons. 8% of the boutons have a rather homogeneous vesicle population (prevalence of round vesicles, ratio 1:1). Synaptic specializations of Gray's type II or of an intermediate type were found in the boutons belonging to the first group (78% of the boutons). Specializations of Gray's type I were found in the other bouton groups (8% of the boutons).

Animals↗