[Anatomo-radiologic correlation of the head of the goat of the canary breed (Capra hircus L.)]. / Correlación anatomo-radiológica de la Cabeza en la Cabra de Raza Canaria (Capra hircus L.).

A radiologic and tomographic study was made of the cranioencephalic topography of canary goats of medium weight and size. In a first step, the exocranialis references corresponding to an axis designed at the level of the meatus acusticus externus and parallel to the basicranial axis were anatomically and radiologically defined. Conventional stereotaxic techniques were then used to reach the standard position of the head in order to obtain macroscopical cross sections at different levels perpendicular to the base of the cranium. In a second step, a tomographic study was made to confirm the design of the axis.

Projections from the visual areas to the neostriatum in rats. A re-examination.

Neostriatal afferents from the primary visual cortex in rats were studied using dextran-biotin, biocytin, and Fluoro-Gold. The area V1 was found to project only to a dorsomedial, longitudinal region of neostriatum (NS), bordering on the lateral ventricle and subcortical white matter. The preterminal fibres in the NS form fluffs which increase in number and density in the cases with larger injections. This target region is poorly stained for calbindin and yet belongs to the matrix compartment. The secondary visual areas also project to the dorsomedial NS region but they also innervate the deeper tissue in the same general region. Iontophoresis of Fluoro-Gold into the dorsomedial NS labelled some pyramidal neurones in the fifth layer of the primary visual cortex. The cortical areas that surround the visual cortical complex project to other regions of the NS: the somatosensory cortex to a dorsolateral longitudinal region and the auditory area to the medial half of the caudalmost portion of NS. Thus, major sensory cortical divisions project to non-overlapping NS regions. Since NS in monkeys and cats does not receive afferents from the primary visual cortex and in a number of other species does, we conclude that visual systems in different mammals differ with respect to their projections to NS.

Anti-inflammatory drugs suppress injury-induced NADPH-d activity in CA1 pyramidal neurones.

Inducibility of NADPH-diaphorase (NADPH-d) or nitric oxide synthase (NOS) has been demonstrated in pyramidal neurones of the hippocampus, but the mechanisms of this induction are not known. The present study aimed to assess the role of anti-inflammatory drugs in injury-induced production of NADPH-d/NOS in CA1 pyramidal neurones. We found that either a steroid, dexamethasone or a non-steroid, indomethacin, prevents induction of these enzymes. We also found that NO is not necessary for the induction. None of the three drugs used had detectable effect on the neurones which contain constitutive NADPH-d/NOS.

NADPH-diaphorase (NOS) is induced in pyramidal neurones of hippocampal slices.

We found NADPH-diaphorase (presumably identical with nitric oxide synthase) in pyramidal neurones of the hippocampus in slices that stayed in a chamber for 30 min or longer. In some instances parallel slices showed normal membrane properties when studied electrophysiologically. In freshly made slices the pyramidal neurones were not stained. Thus, after induction of the enzyme, the hippocampal pyramidal neurones can synthesize nitric oxide which may serve as a retrograde messenger in long-term potentiation. The enzyme may also play a role in cell loss seen in slices which stayed in a chamber for 9-22 h before fixation.

Bilateral induction of NADPH-diaphorase activity in neocortical and hippocampal neurons by unilateral injury.

Unilateral injury of the cerebral cortex or hippocampus induced a bilateral appearance of NADPH-diaphorase in some pyramidal neuronal and glial cells of both structures. Only in the cerebral cortex, near the needle track, did some V layer pyramidal neurons contain so much of this enzyme that they looked to be stained by the Golgi method. The induction of NADPH-diaphorase in a subset of cortical and hippocampal neurons in both hemispheres after unilateral injections of either cysteamine or artificial cerebro-spinal fluid suggests the existence in the isocortex and the hippocampus of a selective signalling system which may play a role in recovery of function following local brain damage.

[Mechanisms of development of the dome in the semicircular canals of birds. II. Cellular reorganization]. / Mecanismos de desarrollo de la cúpula en los conductos semicirculares de las Aves. II. Reorganizacion celular.

A light microscopic study of the epithelia of the crista ampullaris of the semicircular canals of the embryonic chicken indicates that the epithelial cells undergo irregular degenerative changes, with continual mitotic replacement of surface cells. The cupula develops over the surface epithelia through vesicular secretions containing acidophils fibrillar material mixed with globular formations derived from fragmentation of the surface epithelial cells. Electron microscopic studies demonstrate the mode of secretion of rounded or oval supraepithelial bodies from surface epithelium, contributing to the development of the cupula ampullaris. These observations provide evidence of cytoplasmic contributions of surface epithelial cells of the crista ampullaris contributing to the development and continued reorganization of the cupula ampullaris during embryonic development.

[Mechanisms of development of the dome in the semicircular canals of birds. I. Cellular secretion]. / Mecanismos de desarrollo de la cúpula en los conductos semicirculares de las aves. I. Secreción celular.

A study of the crista ampullaris of the vestibular apparatus was carried out in chicken embryos. The study group included embryos between stages 24 and 39 of Hamburger-Hamilton. This study elucidates the relationship of the cupula with respect to the epithelium of the crista ampullaris. With electron microscopic examination, the rough endoplasmic reticulum of the crista epithelial sustentacular cells at developmental stage of 31 H-H, demonstrated dilatations containing secretory material. Vesicles, with adhering ribosomes appear to be formed from these dilatations. At later stages of development, the vesicular material took on the characteristics of the fibrillary material composing the cupula. In some cells, secretory vesicles are seen near the apical border of these cells, where they apparently secrete vesicular contents into the endolymphatic space, contributing to the formation of the cupula.