摘要:

The potassium pyroantimonate‐osmium method was employed to determine the distribution of cations in the superficial pineal gland of the Mongolian gerbil. The reaction product in the glands was presumed to be calcium following the use of both the chelator EGTA and x‐ray microanalysis. A gradient of reaction product was found in the pineal with the highest concentrations occurring in and around the pineal concretions (PC). The periphery of mature PC demonstrated a heavy precipitate as did the surrounding pinealocytes. PC‐associated pinealoeytes contained reaction product in many organelles, including small vesicles that appeared to be opening in the direction of the concretions. The vacuoles of the pinealocytes contained various concentrations of precipitate. The results obtained in the present investigation have led to a hypothesis on the formation of pineal concretions: (1) a pinealocyte vacuole is formed, (2) calcium is transported to the vacuole, (3) the cation content of the vacuole increases, and (4) the cations precipitate into an immature concretion. Fibrillar material and an amorphous substance located within the pinealocyte vacuole appear to form cation containing vesicles that contribute to the periphery of the developing PC, resulting in the continued growth of the concr

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00221.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The effects of pinealectomy and of melatonin administration on prostaglandin E synthesis in the medial basal hypothalamus were studied in male rats. Melatonin treatment significantly decreased prostaglandin E release from the medial basal hypothalamus in pinealectomized rats. The results of the present study suggest that melatonin modulates hypothalamo‐hypophyseal function, at least in part, via inhibition of hypothalamic prostaglandin synthesi

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00222.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

In view of the increasing interest in the central innervation of the mammalian pineal gland, this aspect was studied in depth in the rat. This species is especially suited since the nerve fibers in question form a distinct bundle running from the deep to the superficial pineal gland through the pineal stalk. The axons were counted and analysed ultrastructurally in the pineal stalks cut transversely at three levels (proximal, intermediate, and distal) relative to the neural axis and in longitudinal sections. The number of nerve fibers was highly variable, ranging from 551 to 1, 132 proximally and from 110 to 448 distally, indicating that many fibers terminate in the stalk or leave the stalk after forming a loop. Large myelinated axons, which are abundant proximally, appear to lose their sheaths along their course through the stalk. Most of the axons were small and unmyelinated. A few of these had the appearance of sympathetic fibers and disappeared after sympathectomy. Others contained abundant neurosecretory granules, and, according to the literature, may originate in the hypothalamic paraventricular nuclei. The majority of the small axons which are apparently devoid of granules and dense‐cored vesicles may come from the habenular nuclei and the stria medullaris. In addition to axons, the stalk contains astrocytes, a few oligodendrocytes and Schwann cells, as well as pinealocytes identical to those of the superficial pineal glan

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00223.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

This report describes the response of both the superficial and deep components of the gerbil pineal gland to a 30‐min pulse of fluorescent light at the time of the nocturnal peak in pineal activity. When gerbils were maintained in a 14 h light: 10 h dark photoperiod, mean melatonin concentrations in the superficial pineal gland ranged between 72 and 108 pg/gland during the day and first 4 h of darkness, rose to a peak of 399 pg/gland 7 h after lights out, then returned to basal levels at the expected time of light onset. Pineal melatonin contents were reduced to daytime values within 30 min after exposure of gerbils to fluorescent light at the time of the nocturnal peak. These changes in superficial pineal melatonin content reflected the circadian pattern in serotonin N‐acetyltransferase (NAT) activity, as would be expected if NAT controls melatonin synthesis. In addition to the reductions in NAT and melatonin content induced by nocturnal photic stimulation, there was a 30% reduction in mean pinealocyte nuclear volume. A nocturnal elevation in melatonin content but not in NAT activity occurred in the deep pineal gland. Unlike the superficial pineal gland, the deep pineal gland did not demonstrate a response in melatonin content, NAT activity, or pinealocyte nuclear volumes upon exposure of gerbils to light at the time of the nocturnal peak in superficial pineal activ

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00224.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Carbidopa, an aromatic acid decarboxylase inhibitor, has been shown to significantly decrease the pineal concentration of melatonin, N‐acetyl serotonin (NAS), serotonin (5‐HT), and 5‐hydroxyindoleacetic acid (5‐HIAA) but not the hypothalamic concentrations of these indoles. Increased levels of 5‐hydroxytryptophan (5‐HTP) indicate that carbidopa directly inhibits 5‐HTP decarboxylation, thus limiting 5‐HT production. Possible practical implications of selective inhibition of pineal indoleamines by carbidop

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00225.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Substance P (SP) immunoreactivity was studied in the epithalamus of intact and superior cervical ganglionectomized female rats by using the peroxidase‐antiperoxidase immunocytochemical technique. Cells containing immunoreactive SP were located in the medial habenula, and SP fibers were observed in the lateral habenula, habenular commissure, pineal stalk, and the pineal organ. Bilateral removal of the superior cervical ganglia did not affect the immunocytochemical staining of SP‐containing cells and fibers 15–30 days later. It is suggested that habenular neurons containing SP send projections into the pineal organ of th

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00226.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Previous studies have provided evidence that pineal‐mediated gonadal atrophy involves the luteinizing hormone‐releasing hormone (LHRH) system in some rodents. The purpose of the present study was to visualize the LHRH system in the brain of the white‐footed mouse by immunocytochemical methods and to assess the influence of blinding or melatonin on the LHRH immunostaining characteristics of the median eminence. Six intact adult female mice and six adult males (two intact, two blinded, and two with subcutaneous melatonin‐beeswax implants) treated for 6 wk were sacrificed by perfusion of fixative, and their brains were removed, cut into 60‐μm sections and stained for LHRH by the peroxidase‐antiperoxidase (PAP) method. Since the tissues were batch‐processed in separate wells in a common chamber, semiquantitive comparisons may be made between similar sections from animals subjected to different treatments. The testes were also collected and prepared for microscopic examination. The distribution of LHRH‐stained cell bodies and fibers was found to be essentially the same as has been described in other rodents, i.e., predominantly confined to the preoptic area and hypothalamus. The perikarya appear as unipolar and bipolar fusiform cells with “beaded fiber” type processes. In sections that included the median eminence of the blinded and melatonin‐treated males, the degree of immunopositive staining appears to be greater than in the median eminence of untreated mice. The histological appearance of the testes from the treated animals revealed a profound inhibition of gametogenesis. These observations support the suggestion that pineal‐mediated gonadal atrophy is the result of an inhibition of LHRH release

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00227.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The effects of pinealectomy on plasma follicle‐stimulating hormone (FSH), luteinizing hormone (LH), and growth hormone (GH) concentrations were studied for a period of 9 weeks in pigeons reared under naturally increasing day length. After pinealectomy, plasma LH and GH concentrations decreased in both sexes when compared with sham‐operated birds. In pinealectomized female pigeons, the plasma level of FSH was elevated, while in male birds the effect on FSH was negligible. A trend toward increased weight of testis, ovary, and oviduct was also seen after pinealectomy, but the increase was not statistically significant.The present results suggest that pinealectomy is able to modify the secretion of gonadotrophins and GH in the pigeon and indicate a stimulatory role for the pineal gland in LH and GH secretion and, in female pigeons, an inhibitory role in FSH secret

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00228.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00229.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0742-3098    

DOI:10.1111/j.1600-079X.1984.tb00230.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY