The pineal body of the dog

A technique is described for finding the pineal body of the dog. The posterior half of the skull is cut a little behind the parietofrontal suture, through the occipital condyles. The cerebral hemispheres and cerebellum are carefully sliced, disclosing the pineal at the frontal edge of the colliculi. Two types of cells are present, those with completely round nuclei, and others with vesicular and variably shaped nuclei. In the histological pattern, ependymal cells were observed on the edges, pinealocytes and glial cells within the gland.     

Demonstration of the neural crest origin of type I (APUD) cells in the avian carotid body,using a cytochemical marker system

Summary The biogenic amines present in the carotid body Type 1 cells of two avian species (Japanese quail and chicken) were identified, by microspectrofluorometry of formaldehyde-induced fluorescence, as dopamine and 5-hydroxytryptamine respectively. These and other cytochemical properties establish the cells as members of the APUD series.Grafts of the neural rhombencephalic primordium from 6 to 10-somite quail embryos were implanted in the appropriate region of chick embryos of the same age. After up to 11 days incubation the carotid bodies of the host were freeze-dried and treated with hot formaldehyde vapour. The carotid body Type 1 cells in the chick host were identified, by the presence of dopamine and the absence of 5-HT, as cells from the quail neural crest.The dopamine phenotype in cells of quail origin thus provides a cytochemical marker which may be used for other allograft experiments. The present work confirms earlier findings, using a biological (nuclear chromatin) marker, which showed the avian carotid body to be of neural crest origin.     

APUD cells the human pulmonary neuroendocrine system

Literature data are presented on the anatomy of the diffuse neuroendocrine system (DNES) of the human lungs. The following subjects are discussed: physiological effects of the biologically active substances synthesized, stored, and secreted by the pulmonary neuroendocrine cells; their immunomodulating function; and the role of the DNES in the pathogenesis of bronchial asthma and other bronchopulmonary diseases.     

The nervous control of blood flow to the pineal body

The minimum nutritional flow of blood to the pineal body was measured in intact rats and in those in which the superior cervical ganglia have been bilaterally removed or decentralized. In addition, blood flow was determined during infusions of high physiologic doses of epinephrine, norepinephrine or vasopressin. Either surgical procedure reduced the flow to the pineal by one-third without a loss in organ weight. In addition, the ability of the pineal to make a compensatory vasomotor response to pressor quantities of norepinephrine or vasopressin was lost. There was no evidence of denervation sensitization for vasomotor responses. The high flow of blood to the denervated pineal body suggests a continued high level of metabolic activity.     

An embryonic pineal body as a multipotent system in cell differentiation

The differentiating potency of pineal cells from 8-day quail embryos was studied with cell culture. It was found that the differentiation of striated muscle fibres occurred abundantly in the pineal cells cultured in hypertonic culture conditions. Muscle nature of these fibres was confirmed by utilizing the antiserum against the striated muscle type creatine kinase (MM-CK). When CO2, NAHCO3, NaCl, KCl and MgCl2 were added in hypertonic concentrations, extensive myogenesis occurred in cultured pineal cells. Myogenesis in pineal cultures began as early as 2 days and, after 3 days in the medium with 75 mM additional NaCl, reached 100-fold when compared with that in the isotonic medium. Muscle fibres from pineal cells in culture were similar in morphology to the skeletal muscle fibres of mesodermal origin in situ. Myogenesis of pineal cells under hypertonic conditions was accompanied by the synthesis of a unique 56 x 10(3) Mr protein, which was not found in the intrinsic muscle cells. Clonal cell culture revealed that about 80% of clonable pineal cells were myogenic precursors. Pineal cells of 8-day quail embryos were not only myogenic but oculopotent (melanogenic and lentoidogenic) in cultures. This study examined whether multipotential progenitor cells with both potentials are present in the pineal or not. The results showed that at least 16% of all clonable pineal cells were multipotent precursors. The embryonic pineal is considered to be a typical multipotent system in parallel with the pigmented and neural retina, the neural crest and the teratocarcinoma.     

Organ culture of the goldfish pineal body

Summary The ultrastructure and biochemistry of the goldfish pineal organ were examined in expiants cultured for 1, 3, and 6 days. All four cell types (photoreceptor, supportive, ganglion, phagocytic) were identified; they exhibited many of the characteristics of these cells in vivo. Exceptions included a gradual disorganization of the outer segments and reduction of synaptic ribbons in photoreceptors with time in culture. In addition, there was a marked proliferation of endoplasmic reticulum in both photoreceptor and supportive cells. The indoles 5-hydroxytryptophan, serotonin, 5-hydroxyindoleacetic acid, 5-methoxytryptophol, and melatonin were separated in expiants by high performance liquid chromatography using electrochemical detection. Serotonin levels could be depleted by p-chlorophenylalanine and elevated by nialamide or by adding 5-hydroxytryptophan to the culture medium. These findings suggest that organ culture may be a useful model for study of regulatory processes related to the photoneuroendocrine functions of the teleost pineal organ.     

Spontaneous pineal body tumours (pinealomas) in Wistar rats; a histological and ultrastructural study

The pathology of 5 cases of pinealomas in Wistar rats used in long-term toxicological studies is described both grossly, microscopically and ultrastructurally, together with a review of the related literature.