ABSTRACT
In this paper the postnatal changes in the cytoskeleton of the rat optic nerve fibers are described and quantified. These changes are also compared with other parameters such as myelination and axonal caliber with the aim of describing a general pattern of optic nerve maturation from a morphological point of view. The results showed that during the first postnatal week microtubules outnumbered neurofilaments but between days 8 and 20 the neurofilaments rapidly increased and on day 20 were about twice as numerous as microtubules. This proportion remained almost unaltered from the end of the third week to the 44th postnatal day. The comparison with other parameters suggested that the cytoskeleton, and in particular the proportion between its components, may be a more reliable index for measuring optic nerve maturation than other variables commonly used.
Subject(s)
Animals, Newborn/growth & development , Cytoskeleton/physiology , Intermediate Filaments/physiology , Microtubules/physiology , Optic Nerve/growth & development , Rats/growth & development , Animals , Axons/physiology , Myelin Sheath/physiology , Optic Nerve/anatomy & histology , Optic Nerve/physiology , Rats, Inbred StrainsABSTRACT
The aim of this paper is to describe the morphological changes induced in the striatum after the administration of haloperidol during the first postnatal month, a period in which a lack of tolerance to treatment with neuroleptics has been reported. At the end of the treatment several morphological parameters were evaluated including neuron size and density and the synaptic profile areas of cross-sectioned dendrites and axon terminals. The results evidenced a loss of the smallest dendritic profiles without the rest of the parameters examined being affected. This response differs from the one observed in the adult rat striatum that does develop tolerance to haloperidol. It seems to more closely correspond to the changes found in the prefrontal cortex, a region that does not develop tolerance after chronic treatment with neuroleptics.
Subject(s)
Corpus Striatum/growth & development , Haloperidol/pharmacology , Animals , Axons/drug effects , Axons/ultrastructure , Corpus Striatum/cytology , Corpus Striatum/drug effects , Dendrites/drug effects , Dendrites/ultrastructure , Haloperidol/administration & dosage , Rats , Rats, Inbred Strains , Time FactorsABSTRACT
A method for staining nervous tissue with Giemsa dye is described. The procedure is easy to perform and works well on paraffin, celloidin and frozen sections. The results combine the properties of the Nissl stains with the polychromatism of the Romanowsky dyes. The method also provides good results for counterstaining autoradiographies, or when applied after horseradish or peroxidase-antiperoxidase techniques. In the latter case, Giemsa dye darkens the immunoreactive product in the same manner as osmium tetroxide but avoids the well-known risks of handling this toxic agent.
Subject(s)
Azure Stains , Brain/anatomy & histology , Phenothiazines , Animals , Horseradish Peroxidase , Immunoenzyme Techniques , Neuroglia/ultrastructure , Neurons/ultrastructure , Rats , Rats, Inbred StrainsABSTRACT
It is well known that carbonic anhydrase plays an important role in the physiological responses of carotid-body chemoreceptors to hypercapnia. Nevertheless the precise location of the enzyme within the carotid body has been a matter of controversy for many years. Using the Hansson method we found histochemical evidence that this enzyme is localized in type I cells. Type II cells and nerve terminals did not show enzymatic activity. These results allow us to define the carotid body as a secondary receptor in the context of the "acidic hypothesis" of transduction in the carotid body.
Subject(s)
Carbonic Anhydrases/metabolism , Carotid Body/metabolism , Carotid Sinus/innervation , Animals , Carotid Body/cytology , Cats , Chemoreceptor Cells/metabolism , Histocytochemistry , MaleABSTRACT
Two series of Wistar rats were treated with Haloperidol and the striata were stained with two different modifications of the Golgi method. The experimental animals of the first series received a single dose of Haloperidol i.p. and were sacrificed half an hour after the injection. The experimental rats of the second series were treated chronically with Haloperidol, beginning with 5 mg/kg and increasing this dose daily 0.2 mg/kg to reach a final dose of 10 mg/kg after four weeks of treatment. There were no differences in the staining of both series of animals when compared with their controls, whatever modification of the Golgi method was employed. As these results contradict those of Danner and Pfister (1982) the possible reasons of such a discrepancy are discussed.
Subject(s)
Corpus Striatum/drug effects , Haloperidol/pharmacology , Staining and Labeling , Animals , Corpus Striatum/anatomy & histology , Dose-Response Relationship, Drug , Male , Neurons/drug effects , Neurons/ultrastructure , Rats , Rats, Inbred Strains , Receptors, Dopamine/drug effectsABSTRACT
Light- and electron-microscopic methods for nerve fiber counting and diameter measuring are described. These methods were applied to the rat optic nerve. Differences between light- and electron-microscopic results are shown. Coincidences and divergences with the current literature data are discussed.
Subject(s)
Nerve Fibers/ultrastructure , Optic Nerve/ultrastructure , Animals , Cell Count , Microscopy, Electron , RatsABSTRACT
A technique which permits the in vitro study of zinc deficiency in early embryos of Gallus domesticus is described using dithizone as a chelating agent. Zinc deficiency produces specific and constant lesions which are more severe as the embryo is cultivated in more early stages. The most serious alterations affect growth in general and the differentiation of the nervous system and mesoderm.
