Effect of estradiol on the cyclic AMP content of the pineal body of the male rat.
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Animals↗
Biomedical subjects
M Karasek
Publications and source records attributed to M Karasek.
Inverse correlation between "synaptic" ribbon number and the density of adrenergic nerve endings in the pineal gland of various mammals.
The number of "synaptic" ribbons was inversely correlated with the density of the adrenergic nerve endings of the pineal gland compared among a diverse group of species including the fox, cat, rat, cotton rat, white-footed mouse, Djungarian hamster, ground squirrel, and chipmunk. The concentration of norepinephrine paralleled the number of adrenergic nerve terminals in the pineal glands of the cotton rat, rat, and ground squirrel, the only species in which norepinephrine concentrations were measured. The number of ribbon fields paralleled numbers of "synaptic" ribbons in all species examined. Adrenergic nerve endings were observed primarily within the perivascular spaces, although some endings also were found among parenchymal cells. Adrenergic nerve endings forming synaptic junctions with pinealocytes were not observed in any of these species, nor was there any physical association between these nerve endings and "synaptic" ribbons.
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Inclusion bodies in pinealocytes of the cotton rat (Sigmodon hispidus). An ultrastructural study and X-ray microanalysis.
Pinealocytes of the cotton rat (Sigmodon hispidus) often contain large (2-6 micron diameter) intracytoplasmic inclusions, the function of which is not known. These inclusions may represent nucleolus-like bodies, mineral deposits, secretory products or viral inclusions. In this study these inclusions were classified as type A, B or C inclusions based on the amount of electron-dense material interspersed within the finely granular material comprising the bulk of these inclusions. Each type of inclusion was analyzed by X-ray microanalysis and enzymatic proteinaceous digestion. X-ray microanalysis of these inclusions differed both quantitatively and semiquantitatively from that of human or gerbil pineal concretions, the latter two of which are extracellular deposits. Pronase, a proteolytic enzyme, digested the electron-dense material only after longer times of tissue exposure to this enzyme in contrast to the easily digested, finely granular matrix-like material of these inclusions. Such intrapinealocytic inclusions have only been observed in the cotton rat. Their functional significance remains unknown.
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Ultrastructure of the pineal gland of the brush mouse (Peromyscus boylei): influence of long and short photoperiod.
The ultrastructure of the pineal gland of wild-captured brush mice (Peromyscus boylei) was examined. A homogeneous population of pinealocytes was present in the pineal gland of this species. The Golgi apparatus, granular endoplasmic reticulum, mitochondria, lysosomes, dense-core vesicles, vacuoles containing fluocculent material, clear vesicles, microtubules and glycogen particles were consistent components of the pinealocyte cytoplasm; infrequently-observed organelles included centrioles, "synaptic" ribbons, subsurface cisternae, multivesicular bodies, lipid droplets and annulate lamellae-like structures. Quantitative comparison of pinealocyte ultrastructure revealed larger cross-sectional areas of cytoplasma, nucleus, Golgi apparatus, granular endoplasmic reticulum, mitochondria and vacuoles containing flocculent material as well as higher number of dense-core vesicles in the animals kept in short photoperiod (LD 8 : 16) as compared to those in animals kept in long photoperiod (LD 16 : 8). These observations suggest that restricting the amount of light to which animals are exposed activated the pinealocytes of brush mice.
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Effect of superior cervical ganglionectomy on the ultrastructure of the pinealocyte in the cotton rat (Sigmodon hispidus).
The ultrastructure of pinealocytes was examined morphometrically in superior cervical ganglionectomized and sham-operated cotton rats. Following denervation, the pinealocytes decreased in size. Reduced areas of the nucleoli, Golgi apparatus, granular endoplasmic reticulum, mitochondria, and vacuoles containing a flocculent material as well as a decreased number of dense-core vesicles were noted. In contrast, the numbers of "synaptic" ribbons and ribbon fields increased. The nature of ultrastructural changes observed in the cotton rat pinealocyte after sympathectomy may indicate a diminution of the presumptive secretory processes of this cell. The presence of a small number of myelinated and unmyelinated axons in the pineal gland of the cotton rat following superior cervical ganglionectomy suggests that the sympathetic nerve fibers from the superior cervical ganglia do not comprise the only source of innervation to the pineal. Additionally, the presence of striated muscle fibers has been observed in the present study in the pineal gland of the cotton rat which heretofore has not been reported in this species.
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A procedure for the isolation of primary cultures of melanocytes from newborn and adult human skin.
A method to obtain high-density primary cultures of adult and neonatal human melanocytes is described. Keratinocytes and melanocytes are coisolated from split-thickness sections fo neonatal foreskin obtained after circumcision, or from adult facial skin removed for cosmetic correction. Cells are released by trypsin and are plated in McCoy's 5A medium containing cholera enterotoxin (1 X 10(-9) M) and isobutylmethylxanthine (3.3 X 10(-5) M) to enhance melanocyte and keratinocyte multiplication. Keratinocytes and melanocytes are allowed to grow for 1 week. To remove associated keratinocytes, cells are exposed to 5-fluorouracil (5-FU) (1.92 X 10(-5), 3.84 X 10(-5), 1.92 X 10(-4) M). In the presence of low concentrations of 5-FU, keratinocytes are selectively destroyed within 3 weeks, while melanocytes continue to multiply and to form pigment. The differential effect of 5-FU on the multiplication of keratinocytes and melanocytes provides a simple method for obtaining cultures of melanocytes free from other nondendritic cell types present in the epidermis.
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Substrate adherence of newborn and adult human keratinocytes.
A method to detect and analyze the proteins transferred to a collagen substrate following interaction of normal human keratinocytes with a collagen substrate is described. Keratinocytes are allowed to attach to a collagen substrate for 1 hour, and the attached cells are lysed with 0.1 N NaOH. When the keratinocytes are prelabeled with 3H-amino acids, cell surface proteins are transferred from the keratinocyte to the collagen substrate. The transferred proteins cannot be removed from the substrate by sulfhydryl reducing reagents, high concentrations of urea, or metal chelators. Treatment of the attached proteins with proteolytic enzymes (trypsin chymotrypsin) or with 2 M NaBr partially releases the proteins. More specific labeling of the attachment proteins can be obtained using 3H-tyrosine instead of a complete amino acid mixture. 3H-fucose is also incorporated and transferred, suggesting that one of the components of the attachment protein(s) is a glycoprotein. Antibodies prepared in rabbits to the attachment proteins inhibit the adherence of both primary and first-passaged keratinocytes, suggesting that these proteins may be a part of the protein glycoprotein complexes on the surface of keratinocytes involved in the adherence of keratinocytes to basement membranes.
Adult↗
Prolactinemia and sexual impotence: the effects of treatment with bromocriptine.
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Adult↗
Effects of advancing age on the ultrastructure of pinealocytes in the male white-footed mouse (Peromyscus leucopus).
Quantitative comparison of pinealocyte ultrastructure in 3-month-old and 28-month-old male white-footed mice (Peromyscus leucopus) revealed decreases both in the area of the Golgi apparatus and in the number of dense-core vesicles. In contrast, no differences between these two age groups were noted in the areas of granular endoplasmic reticulum, vacuoles with flocculent content, lysosome-like bodies, or mitochondria. Nor were any changes between groups of mice apparent in pinealocyte nuclear or cytoplasmic areas, nuclear: cytoplasmic ratios, or the number of pinealocyte nuclei per unit area. Areas of unusual, annulate lamellae-like structures were increased in the pinealocytes of a group of 28-month-old mice. These observations suggest a possible age-associated decrease in the neurosecretory-like (but not ependymal-like) secretory process in the pinealocyte of white-footed mice.
Aging↗
Ultrastructure of the pineal gland of the fox.
The ultrastructure of the pineal gland of the fox was examined and compared with that of other mammals. The pineal gland of the fox is composed of two different populations of pinealocytes (I and II). The pinealocytes I were distributed homogeneously throughout the parenchyma, while pinealocytes II were located generally near blood vessels. A Golgi apparatus, granular endoplasmic reticulum, mitochondria, lysosomes, centrioles, and cilia were present in both cell populations. A characteristic feature of pinealocytes I was the presence of dense-core vesicles, presumably of Golgi origin; whereas glycogen deposits and pigment granules were common features of pinealocytes II. In addition to the pinealocytes, the parenchyma contained fibrous astrocytes. The capillaries of the pineal gland of the fox consisted of a nonfenestrated endothelium. Numerous never fibers, presumably adrenergic, were observed throughout the parenchyma.
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Localization of enkephalin-like immunoreactivity in the cat carotid and aortic body chemoreceptors.
The purpose of this study was to determine if enkephalin-like immunoreactivity was present in the glomus cells of the carotid and aortic body peripheral arterial chemoreceptors. Cat carotid and aortic bodies were reacted with antisera to met- and leu-enkephalin using the indirect peroxidase-antiperoxidase immunocytochemical method of Sternberger (1979). Both the carotid and aortic bodies demonstrated clusters of immunoreactive cells for both met- and leu-enkephalin. Additionally, met-enkephalin-like immunoreactivity was observed in many of the dense-core vesicles of the glomus cells of the carotid body. The glomus cells of these chemoreceptors are known to contain catecholamines which may modulate chemoreceptor activity. The presence of opioid peptide-like substances co-existing with the glomus cell catecholamines, perhaps in the same vesicles, may have important implications for a trophic influence of these peptides on glomus cell chemoreceptor modulation.
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Ultrastructure of the pineal gland of the eastern chipmunk (Tamias striatus).
The ultrastructure of the pineal gland of the wild-captured eastern chipmunk (Tamias striatus) was examined. A homogenous population of pinealocytes was the characteristic cellular element of the chipmunk pineal gland. Often, pinealocytes showed a folliclelike arrangement. Mitochondria, Golgi apparatus, granular endoplasmic reticulum, lysosomes, centrioles, dense-core vesicles, clear vesicles, glycogen particles, and microtubules were consistent components of the pinealocyte cytoplasm. The extraordinary ultrastructural feature of the chipmunk pinealocyte was the presence of extremely large numbers of "synaptic" ribbons. The number of "synaptic" ribbons in this species exceeded by a factor of five to 30 times that found in any species previously reported. In addition to pinealocytes, the pineal parenchyma contained glial cells (oligodendrocytes and fibrous astrocytes). Capillaries of the pineal gland of the chipmunk consisted of a fenestrated endothelium. Adrenergic nerve terminals were relatively sparse.
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A quantitative ultrastructural study of the pinealocyte of the chipmunk (Tamias striatus) during the daytime and at night.
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Animals↗
Day-night differences in the number of pineal "synaptic" ribbons in two diurnal rodents, the chipmunk (Tamias striatus) and the ground squirrel (Spermophilus richardsonii).
Daytime numbers of pineal "synaptic" ribbons higher than reported in the pineal gland of any other mammalian species were observed in two diurnal rodents, the eastern chipmunk and Richardson's ground squirrel. The number of "synaptic" ribbons was lower during the daytime and higher at night in both of these species.
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Presence of dense-core vesicles in pinealocytes of the cat.
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Animals↗
Ultrastructure of pinealocytes of the kangaroo rat (Dipodomys ordi).
The ultrastructure of the pinealocytes of the wild-captured ord kangaroo rat (Dipodomys ordi) was examined. A homogeneous population of pinealocytes was present in the pineal gland of the kangaroo rat. The Golgi apparatus, granular endoplasmic reticulum, mitochondria, lysosomes, dense-core vesicles, vacuoles containing a flocculent material and lipid droplets were consistent components of the pinealocyte cytoplasm, whereas infrequently-observed organelles included centrioles, multivesicular bodies, subsurface cisternae, "synaptic" ribbons and cilia. The number of dense-core vesicles was relatively high and dense-core vesicles and vacuoles containing a flocculent material were present in the same cell. Although it has been recently suggested that two different secretory processes, i.e., neurosecretory-like (Golgi apparatus - dense-core vesicles) and ependymal-like (granular endoplasmic reticulum - vacuoles containing a flocculent material) may be involved in different regulatory mechanisms in the pinealocytes, the definitive answer to this is still far from clear. Therefore, the pineal gland of the kangaroo rat appears to be a good model for the study of the potential relationship between these two secretory processes, especially in respect to seasonal changes.
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"Synaptic" ribbons and spherules of the rat pineal gland: day/night changes in vitro?
In the present study pineal glands of rats aged 69-71 days were studied in vivo and in vitro with respect to day/night changes of "synaptic" ribbons and spherules. It was found that ribbons outnumber spherules by a factor of 3. In vivo, both ribbons and spherules show a roughly 3-fold increase in number at 1 a.m. when compared to 1 p.m. Up to 39 h in vitro, the two structures in question did not reveal day/night differences in amount, suggesting that diurnal rhythmicity of the gland did apparently not persist in organ culture. After 3 h in organ culture, the spherules, but not the ribbons, showed a striking increase in number, showing that ribbons and spherules may be governed by different mechanisms.
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