Synaptic junctions between sympathetic axon terminals and pinealocytes in the monkey Macaca fascicularis

Ling, Eng‐Ang; Tan, Shin Hwei; Wong, Weng-Fai

doi:10.1007/bf00187524

Cited by 9 publications

(5 citation statements)

References 27 publications

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“…The activated microglial profile is observed in the brain following viral or bacterial infection, traumatic injury, stroke, or in the context of a neurodegenerative disease (Licinio et al, 1993; Ling and Wong, 1993; Katila et al, 1994; Mittleman et al, 1997; Munn, 2000; Vargas et al, 2005; Fabene et al, 2010) and can play both damaging and neuroprotective roles (Marchetti et al, 2005; Streit, 2005). Microglia are also primarily in the activated state in the normal neonatal brain through the first postnatal week (Ling et al, 1990; Wu et al, 1992; Ling and Wong, 1993; Dalmau et al, 1997) and contribute to normal neurodevelopmental processes, including axon guidance, neurite growth, pruning, and apoptosis (Mallat and Chamak, 1994; Kingham et al, 1999; Polazzi and Contestabile, 2002; Marin-Teva et al, 2004; Tremblay et al, 2011). Given that microglia are active neonatally and contribute to neurodevelopmental processes known to be involved in sexual differentiation, the natural next question is whether microglia and their signaling are involved in producing sex differences in the brain (Figure 3).…”

Section: Neuroendocrinology Meets Neuroimmunologymentioning

confidence: 99%

Sexual Differentiation of the Rodent Brain: Dogma and Beyond

Lenz¹,

Nugent²,

McCarthy³

2012

Front. Neurosci.

150

102

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Steroid hormones of gonadal origin act on the neonatal brain to produce sex differences that underlie adult reproductive physiology and behavior. Neuronal sex differences occur on a variety of levels, including differences in regional volume and/or cell number, morphology, physiology, molecular signaling, and gene expression. In the rodent, many of these sex differences are determined by steroid hormones, particularly estradiol, and are established by diverse downstream effects. One brain region that is potently organized by estradiol is the preoptic area (POA), a region critically involved in many behaviors that show sex differences, including copulatory and maternal behaviors. This review focuses on the POA as a case study exemplifying the depth and breadth of our knowledge as well as the gaps in understanding the mechanisms through which gonadal hormones produce lasting neural and behavioral sex differences. In the POA, multiple cell types, including neurons, astrocytes, and microglia are masculinized by estradiol. Multiple downstream molecular mediators are involved, including prostaglandins, various glutamate receptors, protein kinase A, and several immune signaling molecules. Moreover, emerging evidence indicates epigenetic mechanisms maintain sex differences in the POA that are organized perinatally and thereby produce permanent behavioral changes. We also review emerging strategies to better elucidate the mechanisms through which genetics and epigenetics contribute to brain and behavioral sex differences.

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Section: Neuroendocrinology Meets Neuroimmunologymentioning

confidence: 99%

Sexual Differentiation of the Rodent Brain: Dogma and Beyond

Lenz¹,

Nugent²,

McCarthy³

2012

Front. Neurosci.

150

102

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“…Synapses are rarely observed between sympathetic nerve endings and pinealocytes in the superficial pineal gland of the rat (Huang and Lin, 1984), but nothing has been found in the literature concerning such synapses in the deep pineal gland of this animal. Conventional electron microscopic studies demonstrate the presence of synapses between presumptive sympathetic nerve endings and pinealocytes in some non-rodents; such synapses occur occasionally in the monkey (Ling et al, 1989(Ling et al, , 1990 and frequently in the tree shrew (Hwang, 1982). Synaptic-like junctions have recently been observed immunoelectron microscopically between nerve fibers immunoreactive for C-terminal flanking peptide of NPY and pinealocytes in the pig (Przybylska-Gornowicz et al, 1997).…”

Section: Relationships Between the Peripheral Fibers And Their Endingmentioning

confidence: 99%

Peptidergic peripheral nervous systems in the mammalian pineal gland

Miyake¹,

Sakai²,

Hira³

1999

Microsc. Res. Tech.

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The distribution and density of tyrosine hydroxylase (TH) and neuropeptide Y (NPY)-immunoreactive, sympathetic fibers and calcitonin gene-related peptide (CGRP)-, substance P (SP)-, and vasoactive intestinal polypeptide (VIP)-immunoreactive, non-sympathetic fibers in the pineal gland, the effects of superior cervical ganglionectomy (SCGX) on these fibers, and the location of their terminals in the pineal gland were compared between rodents and non-rodents. A dense network of TH/NPY-positive fibers is present all over the pineal gland. A less dense network of CGRP/SP- or VIP-positive fibers occurs in the whole pineal gland of non-rodents, but these fibers are usually confined to the superficial pineal gland in rodents. After SCGX, some TH/NPY-fibers remain only in the deep pineal gland in rodents, whereas considerable numbers of these fibers persist throughout the gland in non-rodents. Thus, the remaining fibers, probably originating from the brain, may be more numerous in non-rodents. Since CGRP-, SP- or VIP-immunoreactive fibers in the pineal capsule can be traced to those in the gland, and since these fibers are ensheathed by Schwann cells, it is concluded that these fibers belong to the peripheral nervous system. However, the existence of SP-positive central fibers cannot be denied in some species. In the superficial pineal gland of rodents, sympathetic terminals are mostly localized in perivascular spaces, whereas the parenchymal innervation by sympathetic fibers in the pineal gland is more dense in non-rodents than in rodents. Synapses between sympathetic nerve terminals and pinealocytes occur occasionally in non-rodents, but only rarely in the superficial pineal gland of rodents. The occurrence of the synapses may depend on the frequency of intraparenchymal sympathetic terminals.

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“…Nerve fibers and terminals present in the pineal tissue were considered to belong to sympathetic axons in the rat and monkey, without considering the existence of intrapineal neurons and the central afferentation of the organ by its habenulae and habenular commissure . As already mentioned in the introduction, it seems to be evident that light‐specific information from the retina reaches the pineal organ by central pathways.…”

Section: Discussionmentioning

confidence: 99%

Peripheral autonomic nerves of human pineal organ terminate on vessels, their supposed role in the periodic secretion of pineal melatonin

Silva

Singh

Haldar

et al. 2012

APMIS

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Nonvisual pineal and retinal photoreceptors are synchronizing circadian and circannual periodicity to the environmental light periods in the function of various organs. Melatonin of the pineal organ is secreted at night and represents an important factor of this periodic regulation. Night illumination suppressing melatonin secretion may result in pathological events like breast and colorectal cancer. Experimental works demonstrated the role of autonomic nerves in the pineal melatonin secretion. It was supposed that mammalian pineals have lost their photoreceptor capacity that is present in submammalians, and sympathetic fibers would mediate light information from the retina to regulate melatonin secretion. Retinal afferentation may reach the organ by central nerve fibers via the pineal habenulae as well. In our earlier works we have found that the pineal organ developing from lobular evaginations of the epithalamus differs from peripheral endocrine glands and is composed of a retina-like central nervous tissue that is comprised of cone-like pinealocytes, secondary pineal neurons and glial cells. Their autonomic nerves in submammalians as well as in mammalian animals do not terminate on pineal cells, rather, they run in the meningeal septa among pineal lobules and form vasomotor nerve endings. Concerning the adult human pineal there are no detailed fine structural data about the termination of autonomic fibers, therefore, in the present work we investigated the ultrastructure of the human pineal peripheral autonomic nerve fibers. It was found, that similarly to other parts of the brain, autonomic nerves do not enter the human pineal nervous tissue itself but separated by glial limiting membranes take their course in the meningeal septa of the organ and terminate on vessels by vasomotor endings. We suppose that these autonomic vasomotor nerves serve the regulation of the pineal blood supply according to the circadian and circannual changes of the metabolic activity of the organ and support by this effect the secretion of pineal neurohormones including melatonin.

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Synaptic junctions between sympathetic axon terminals and pinealocytes in the monkey Macaca fascicularis

Cited by 9 publications

References 27 publications

Sexual Differentiation of the Rodent Brain: Dogma and Beyond

Sexual Differentiation of the Rodent Brain: Dogma and Beyond

Peptidergic peripheral nervous systems in the mammalian pineal gland

Peripheral autonomic nerves of human pineal organ terminate on vessels, their supposed role in the periodic secretion of pineal melatonin

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