Morphological evidence for calcium storage in the chromatoid body of rat spermatids

Summary Morphological evidence for probable Ca²⁺ storage in the vesicular elements of the rat spermatid chromatoid body is documented using the K-pyroantimonate method, combined with EDTA chelation. Some vesicles are related to the microtubules associated with the chromatoid body. A possible involvement of Ca²⁺ in the intracellular movement and/or structural integrity of the chromatoid body is discussed.     

Association of Golgi vesicles containing acid phosphatase with the chromatoid body of rat spermatids

The relationship between the Golgi apparatus and the small vesicles associated with the chromatoid body was investigated using a cytochemical technique. It was observed that in early spermatids, when the chromatoid body appears in close contact with the Golgi complex, and all through its migration to the caudal pole of the nucleus, some of the vesicles that accompany the organelle display acid phosphatase activity. It is concluded that these smooth vesicles originate in the Golgi apparatus.     

Morphological evidence for a direct neuroendocrine GABAergic control of the anterior pituitary in teleosts

The anterior pituitary of teleosts is unique among vertebrates in receiving a direct innervation which represents the morphological support of the neuroendocrine control of pars distalis functions. The participation of GABAergic fibers in this innervation was studied by means of immunocytochemistry at the light and electron microscopic levels, using antibodies against GABA. Immunoreactive fibers, characterized by the presence of small clear and dense cored vesicles, were detected in all parts of the gland. Immunopositive terminals were found in close, sometimes synaptic-like, contact with most glandular cell types in the anterior lobe. The data strongly suggest that in teleosts, as in mammals, GABA is involved in the neuroendocrine control of anterior pituitary functions.     

Morphological evidence for a direct neuroendocrine GABAergic control of the anterior pituitary in teleosts

Summary The anterior pituitary of teleosts is unique among vertebrates in receiving a direct innervation which represents the morphological support of the neuroendocrine control of pars distalis functions. The participation of GABAergic fibers in this innervation was studied by means of immunocytochemistry at the light and electron microscopic levels, using antibodies against GABA. Immunoreactive fibers, characterized by the presence of small clear and dense cored vesicles, were detected in all parts of the gland. Immunopositive terminals were found in close, sometimes synaptic-like, contact with most glandular cell types in the anterior lobe. The data strongly suggest that in teleosts, as in mammals, GABA is involved in the neuroendocrine control of anterior pituitary functions.     

Morphological evidence for tracer uptake at the active zones of stimulated frog neuromuscular junction

Lanthanum or ferritin added to the fixative were found in small and non-coated vesicles located at active zones in nerve-muscle preparations stimulated by potassium during cold aldehyde fixation. The presence of labeled vesicles at active zones supports the hypothesis that a double process of exo-endocytosis might occur under moderate stimulation conditions.     

Biochemical evidence for two types of noradrenaline storage particles in rabbit iris

Summary Centrifugation techniques were used to determine the subcellular distribution of noradrenaline (NA) and dopamine -hydroxylase (DH) in the rabbit iris. By application of isopycnic and differential gradient centrifugation methods 2 types of NA vesicles could be demonstrated. Of the total particle bound NA about 70% is associated with light and about 30% with heavy vesicles. For both types of vesicles the distribution of DH reflected that of NA.     

Morphological evidence for the presence of the endogenous guinea-pig retravirus in the lymphoblasts of L2C leukemia

Summary Peripheral blood samples of a transplantable guinea-pig leukemia revealed that, only during the terminal stages of the disease, leukemic cells produce virus particles indistinguishable from the RNA tumor viruses of the Retraviridae family genusOncorna virus B.This study was supported partly by the Israel Cancer Association.     

Histochemical evidence for a somatotopic organization of the rubrospinal projection in the rat

Résumé La technique de l'acétylthiocholine démontrant l'activité de l'acétylcholinesterase fût employée pour indiquer la perte régionale d'enzyme des cellules nerveuse du noyau rouge du rat à la suite d'une lésion du faisceau rubrospinal. Les lesions aux niveaux thoraciques inférieurs du cordon médullaire donnent lieu à une perte d'enzyme des cellules dans la partie ventrale de la moitié caudale du noyau rouge. Cependant, les lésions du faisceau aux niveaux cervicaux du cordon médullaire donne lieu à une perte d'enzyme de la partie ventrale ainsi que de la partie dorsale de la moitié caudale du noyau. On suggère que cela indique une organization somatotopique de la projection rubro-spinale chez le rat.

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Supported by a grant from the Canadian Medical Research Council.     

Morphological evidence for the presence of the endogenous guinea-pig retravirus in the lymphoblasts of L2C leukemia.

Peripheral blood samples of a transplantable guinea-pig leukemia revealed that, only during the terminal stages of the disease, leukemic cells produce virus particles indistinguishable from the RNA tumor viruses of the Retraviridae family genus Oncorna virus B.     

Electrophysiological evidence for the action of light on the pineal gland in the rat

Résumé La lumière a un effet inhibiteur sur l'activité électrique tonique spontanée de l'épiphyse du rat, enregistrée dans l'obscurité. Les éléments photosensibles se trouvent au niveau des yeux. Le fait que la réponse a été bloquée par le chlorure de hexamethonium suggère qu'elle est transmise à l'épiphyse par les nerfs sympathiques postganglionnaires.     

Morphological evidence for electrical synapse of ‘gap’ junction type in another vertebrate receptor

Résumé Une étude des organes tubéreux de grande taille chez un poisson électrique à faible décharge,Sternarchus albiforns a été effectuée en microscopie électronique. Elle a permis d'observer la présence, en plus de la synapse chimique, d'une jonction en «gap» de la synapse électrique.

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Acknowledgments. I am grateful to Dr.T. Szabo for his valuable suggestions. The work was carried out during the tenure of French Govt. Fellowship award to the author who is on leave from Department of Zoology, University of Allahabad, Allahabad, India.     

Evidence for inward calcium current in the absence of external sodium in rat myocardium

Zusammenfassung An Papillarmuskeln von Rattenherzen ist bei Depolarisation mittels Spannungsklemme ein beträchtlicher Einwärtsstrom messbar, dessen Stärke in Na⁺-freier Lösung von der extrazellulären Ca²⁺-Konzentration abhängt. Die kurze Dauer des Aktionspotentials kleiner Nagetiere wird darauf zurückgeführt, dass die K⁺-Konduktivität bei Depolarisation der Zellmembran nicht so stark absinkt wie bei den meisten andern Herzen.

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Supported in part by the Medical Research Council of Canada. Our thanks to Professor Weidmann for his help and advice.     

Morphological effects of estrogen on the female rat liver nucleolus

Summary Prolonged administration of nonphysiological amounts of estrogen induced markedly enlarged nucleoli volumes in rat hepatocytes, indicative of increased nucleolar RNA synthesis. Physiological amounts of drug had no apparent morphological effects on the hepatocytes.I thank Dr L. Biempica, Department of Pathology, Albert Einstein College of Medicine, for the electron microscopy studies.     

Morphological evidence of a polypeptide-like secretory function of the B cells in the mouse synovial membrane

Summary In the synovial membrane of the mouse, morphological features associated with acitve secretion are unusually well developed in cells immediately subjacent to the lining layer (in the position of B cells), comparable to those of cells known to elaborate polypeptides.This work was supported by grant No 74.1.133.4, Institut National de la Santé et de la Recherche Médicale, France.     

Pineal body and urinary sodium excretion in the rat

Zusammenfassung Ein salinischer Extrakt desCorpus pineale erzeugt bei normalen, nicht aber bei adrenalektomierten Ratten eine starke Retention von Natrium. Auf Grund der besonderen anatomischen Verhältnisse des Corpus pineale der Ratte vertreten wir die Auffassung, dass die wirksame Substanz, wahrscheinlich Adrenoglomerulotropin, in der Zirbeldrüse selbst erzeugt wird und nicht aus der Nachbarschaft dort angereichert wird.     

Morphological changes in the pineal gland of the albino rat by hypophysectomy and ovariectomy

Zusammenfassung Die dunklen Pinealzellen waren nach Hypophysektomie beträchtlich vermehrt, während die Vesikeln in den sympathischen Nervenendigungen vermindert waren. Auch nach Ovariektomie waren die dunklen Pinealzellen in geringerem Ausmass vermehrt, ohne dass die Vesikeln vermindert waren. Die osmiophile Granula war sehr spärlich.