Neuroactive steroids influence peripheral myelination: a promising opportunity for preventing or treating age-dependent dysfunctions of peripheral nerves

Axons can represent the majority of the volume of a neuron and are energetically very demanding. Specialized glia ensheathe axons and are believed to support axon function and maintenance throughout life, but molecular details of glia-neuron support mechanisms remain poorly defined. Here we identify a collection of secreted and transmembrane genes that are required in glia for long-term axon survival in vivo. We show that key components of the TGFβ superfamily are required cell-autonomously in glia for peripheral nerve maintenance, although their loss does not disrupt glial morphology. We observe age-dependent neurodegeneration in the absence of glial TGFβ signaling that can be rescued by genetic blockade of Wallerian degeneration. Our data argue that glial TGFβ signaling normally acts to promote axon survival and suppress neurodegeneration.

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Acetyl-l-carnitine Prevents Age-Dependent Structural Alterations in Rat Peripheral Nerves and Promotes Regeneration Following Sciatic Nerve Injury in Young and Senescent Rats

Experimental Neurology ◽

10.1006/exnr.1994.1117 ◽

1994 ◽

Vol 128 (1) ◽

pp. 103-114 ◽

Cited By ~ 8

Author(s):

Clara De Angelis ◽

Carla Scarfò ◽

Marco Falcinelli ◽

Elisa Perna ◽

Emilia Reda ◽

...

Keyword(s):

Sciatic Nerve ◽

Nerve Injury ◽

Peripheral Nerves ◽

Sciatic Nerve Injury ◽

Structural Alterations ◽

Age Dependent

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Peripheral nerves: a target for the action of neuroactive steroids

Brain Research Reviews ◽

10.1016/j.brainresrev.2004.12.021 ◽

2005 ◽

Vol 48 (2) ◽

pp. 328-338 ◽

Cited By ~ 71

Author(s):

Roberto C. Melcangi ◽

Ilaria T.R. Cavarretta ◽

Marinella Ballabio ◽

Emanuela Leonelli ◽

Angelo Schenone ◽

...

Keyword(s):

Peripheral Nerves ◽

Neuroactive Steroids

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Evidence for a Blood Ganglion Barrier in the Superior Cervical Ganglion of the Rat

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053681 ◽

1982 ◽

Vol 40 ◽

pp. 204-204

Author(s):

D. M. DePace

Keyword(s):

Blood Vessels ◽

Superior Cervical Ganglion ◽

Peripheral Nerves ◽

Time Schedule ◽

Transmission Electron ◽

Cervical Ganglion ◽

The Central Nervous System ◽

Cervical Ganglia ◽

Capillary Circulation ◽

And Control

The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions. These same features have been associated with the blood brain barrier of the central nervous system and peripheral nerves. These vessels may perform a barrier function between the capillary circulation and the superior cervical ganglion. The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). Three experimental groups of four animals each were given intravenous HRP (Sigma Type II) in a dosage of.08 to.15 mg/gm body weight in.5 ml of.85% saline. The animals were sacrificed at five, ten or 15 minutes following administration of the tracer. Superior cervical ganglia were quickly removed and fixed by immersion in 2.5% glutaraldehyde in Sorenson's.1M phosphate buffer, pH 7.4. Three control animals received,5ml of saline without HRP. These were sacrificed on the same time schedule. Tissues from experimental and control animals were reacted for peroxidase activity and then processed for routine transmission electron microscopy.

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Effects of Hyperoxia on Lung Utrastructure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067121 ◽

1970 ◽

Vol 28 ◽

pp. 26-27

Author(s):

Gladys Harrison

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Light Microscopy ◽

Oxygen Effects ◽

Age Dependent ◽

The Central Nervous System ◽

The Subject ◽

Space Age ◽

Alveolar Septa ◽

Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

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Intramuscular Nerve and Neuromuscular Junction Alteration In Extraocular Muscles of Diabetic Mice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120102 ◽

1985 ◽

Vol 43 ◽

pp. 682-683

Author(s):

Bruce R. Pachter

Keyword(s):

Diabetes Mellitus ◽

Peripheral Nerves ◽

Sudden Onset ◽

Extraocular Muscles ◽

Diabetic Patients ◽

Oculomotor Palsy ◽

Third Nerve Palsy ◽

Patients With Diabetes ◽

Intramuscular Nerve ◽

Oculomotor Nerves

Diabetes mellitus is one of the commonest causes of neuropathy. Diabetic neuropathy is a heterogeneous group of neuropathic disorders to which patients with diabetes mellitus are susceptible; more than one kind of neuropathy can frequently occur in the same individual. Abnormalities are also known to occur in nearly every anatomic subdivision of the eye in diabetic patients. Oculomotor palsy appears to be common in diabetes mellitus for their occurrence in isolation to suggest diabetes. Nerves to the external ocular muscles are most commonly affected, particularly the oculomotor or third cranial nerve. The third nerve palsy of diabetes is characteristic, being of sudden onset, accompanied by orbital and retro-orbital pain, often associated with complete involvement of the external ocular muscles innervated by the nerve. While the human and experimental animal literature is replete with studies on the peripheral nerves in diabetes mellitus, there is but a paucity of reported studies dealing with the oculomotor nerves and their associated extraocular muscles (EOMs).

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Innervation of endoneurial microvessels in human sural nerve

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125002 ◽

1992 ◽

Vol 50 (1) ◽

pp. 920-921

Author(s):

John L. Beggs ◽

Peter C. Johnson ◽

Astrid G. Olafsen ◽

C. Jane Watkins

Keyword(s):

Blood Flow ◽

Blood Vessels ◽

Blood Supply ◽

Peripheral Nerves ◽

Sural Nerve ◽

Nerve Fibers ◽

Arterial Supply ◽

Autonomic Nerve ◽

Vasa Nervorum ◽

Endoneurial Blood Flow

The blood supply (vasa nervorum) to peripheral nerves is composed of an interconnected dual circulation. The endoneurium of nerve fascicles is maintained by the intrinsic circulation which is composed of microvessels primarily of capillary caliber. Transperineurial arterioles link the intrinsic circulation with the extrinsic arterial supply located in the epineurium. Blood flow in the vasa nervorum is neurogenically influenced (1,2). Although a recent hypothesis proposes that endoneurial blood flow is controlled by the action of autonomic nerve fibers associated with epineurial arterioles (2), our recent studies (3) show that in addition to epineurial arterioles other segments of the vasa nervorum are also innervated. In this study, we examine blood vessels of the endoneurium for possible innervation.

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