The destination of the aged, nonreleasable neurohypophyseal peptides stored in the neural lobe is associated to the remodeling of the neurosecretory axon

2005 ◽  
Vol 68 (6) ◽  
pp. 347-359 ◽  
Author(s):  
Juan Krsulovic ◽  
Bruno Peruzzo ◽  
Genaro Alvial ◽  
Carlos R. Yulis ◽  
Esteban M. Rodríguez
Keyword(s):  
Neural Lobe ◽  
Neurosecretory Axon

scholarly journals Intrahypothalamically Transected Neurosecretory Axons do not Regenerate in the Absence of Glial Cells

1993 ◽  
Vol 4 (2) ◽  
pp. 127-137 ◽  
Author(s):  
H.-Dieter Dellmann ◽  
Jeanine Carithers
Keyword(s):  
Extracellular Matrix ◽  
Optic Nerve ◽  
Sciatic Nerve ◽  
Glial Cells ◽  
Basal Lamina ◽  
Axon Regeneration ◽  
Neural Lobe ◽  
Hypothalamic Area ◽  
Nerve Grafts ◽  
Neurosecretory Axon

Fifteen days after transection of the hypothalamo-neurohypophysial tract at the lateral retrochiasmatic hypothalamic area, neurosecretory axons had vigorously regenerated into transplants of explanted hypophysial neural lobe, to a lesser extent into sciatic nerve transplants, and least into optic nerve transplants. Regenerating axons were always closely associated with the specific glial cells of these grafts. When these glial cells were killed by cryotreatment prior to transplantation, neurosecretory axons did not regenerate into the abundant extracellular matrix of the transplants, including persisting basal lamina tubes in neural lobe and sciatic nerve grafts. The presence of viable glial cells is a prerequisite for neurosecretory axon regeneration.

DISTRIBUTION OF NEUROSECRETORY GRANULES AMONG THE ANATOMICAL COMPARTMENTS OF THE NEUROSECRETORY PROCESSES OF THE PITUITARY GLAND: A QUANTITATIVE ULTRASTRUCTURAL APPROACH TO HORMONE STORAGE IN THE NEURAL LOBE

1976 ◽  
Vol 68 (2) ◽  
pp. 225-NP ◽  
Author(s):  
J. F. MORRIS
Keyword(s):  
Basement Membrane ◽  
Pituitary Gland ◽  
Neurosecretory Granules ◽  
Neural Lobe ◽  
Releasable Pool ◽  
Readily Releasable Pool ◽  
Rat Pituitary ◽  
Axonal Swellings ◽  
Granule Release

SUMMARY The distribution of neurosecretory granules in various anatomical compartments of neurosecretory axons of the neural lobe of the rat pituitary has been studied. Apart from the most anterior tip of the gland, where granules are largely restricted to undilated axons and a few 'swellings', the proportional compartmental storage of granules is essentially homogeneous for the rest of the gland: 13% of granules are found in undilated axons, 31% in axonal 'endings' (which contain microvesicles and abut the basement membrane) and 55% in axonal 'swellings' (which are devoid of significant numbers of microvesicles). These values indicate that the 'endings' contain a much greater proportion of the total number of granules stored in the neural lobe than would be predicted if the readily releasable pool of hormone were composed of all the granules in the 'endings'. Some further constraint on granule release either physiological or anatomical (e.g. the position of the granule in relation to the plasmalemma of the 'ending') must be operative.

Blood flow and functional responses correlate in the ovine neural lobe

1986 ◽  
Vol 373 (1-2) ◽  
pp. 27-34 ◽  
Author(s):  
D.M. Ziedonis ◽  
W.B. Severs ◽  
R.W. Brennan ◽  
R.B. Page
Keyword(s):  
Blood Flow ◽  
Functional Responses ◽  
Neural Lobe

THE UPTAKE OF TRITIATED LYSINE VASOPRESSIN BY RAT AND PIG PITUITARY NEURAL LOBES IN VITRO

1971 ◽  
Vol 50 (4) ◽  
pp. 669-677 ◽  
Author(s):  
B. A. EDWARDS
Keyword(s):  
Tap Water ◽  
Exchange Chromatography ◽  
Control Group ◽  
Breakdown Product ◽  
Nacl Solution ◽  
Water Control ◽  
Neural Lobe ◽  
Lysine Vasopressin ◽  
And Control

SUMMARY Uptake of tritiated lysine vasopressin ([3H]LVP) was studied in halved neural lobes of rats (which had been given either tap water (control group) or 2% (w/v) NaCl solution as drinking water for 4 days) as well as in slices of pig neural lobe. Uptake of radioactivity into the neural lobes was shown but analysis of the extracts of incubated lobes of both species by ion exchange chromatography showed that very little of it remained in the tissue as hormone. In addition, some radioactivity was associated with trichloroacetic acid-insoluble proteins. After 90 min of incubation, and after correction for the breakdown, the uptake of unchanged [3H]LVP, expressed as a tissue: medium ratio, was 0·14 ± 0·04 and 0·09 ± 0·03 (mean ± s.e.m.) for the saline-treated and control rats respectively, while the tissue: medium ratios for the breakdown product(s) were 6·47 ± 0·45 and 5·50 ± 0·36. The results suggest uptake of [3H]LVP into the cell with almost complete intracellular breakdown of the hormone.

Insect peripheral nerves: accessibility of neurohaemal regions to lanthanum

1975 ◽  
Vol 18 (1) ◽  
pp. 179-197 ◽  
Author(s):  
N.J. Lane ◽  
R.A. Leslie ◽  
L.S. Swales
Keyword(s):  
Blood Brain Barrier ◽  
Peripheral Nerves ◽  
Rhodnius Prolixus ◽  
Ionic Lanthanum ◽  
Neurosecretory Axon ◽  
Thin Part ◽  
Free Media ◽  
Exogenous Substances

During incubation in vivo, exogenously applied ionic lanthanum comes to surround the numerous neurosecretory terminals which are found lying within or immediately beneath the acellular neural lamella ensheathing the nerves from fifth instar and adult specimens of Rhodnius prolixus. The lanthanum does not penetrate beyond the cellular perineurium, which completely surrounds the non-neurosecretory axons in these nerves and constitutes a form of ‘blood-brain barrier’. In some cases, however, lanthanum is found in the vicinity of a neurosecretory axon lying beneath the perineurium, where it can be assumed to have leaked in from the neurosecretory terminal lying free in the neural lamella. When nerves are incubated in calcium-free media, regions with an attenuated perineurium become ‘leaky’, in that lanthanum is found lying in those extracellular spaces between axons and glia which lie immediately below the thin part of the perineurial layer. Bathing solutions made slightly hyperosmotic to the haemolymph with sucrose have no apparent disruptive effects on the barrier. When the tissues are incubated in more hypertonic solutions, the perineurial barrier becomes ‘leaky’ throughout, and tracer pervades beyond its cells into all the intercellular spaced between glia and axons. The possible role of the zonulae occludentes in both the maintenance of the perineurial barrier and in the formation of interglial occlusions to local penetration of exogenous substances is considered.

Cerebral metabolic responses and vasopressin and oxytocin secretions during progressive water deprivation in rats

1992 ◽  
Vol 262 (2) ◽  
pp. R310-R317 ◽  
Author(s):  
M. Kadekaro ◽  
J. Y. Summy-Long ◽  
S. Freeman ◽  
J. S. Harris ◽  
M. L. Terrell ◽  
...  
Keyword(s):  
Water Deprivation ◽  
Glucose Utilization ◽  
Extracellular Volume ◽  
Plasma Osmolality ◽  
Ventrolateral Medulla ◽  
Ang Ii ◽  
Neural Lobe ◽  
Arterial Blood ◽  
Organum Vasculosum Laminae Terminalis ◽  
Enhanced Secretion

Progressive water deprivation increased plasma osmolality, plasma Na+ concentration, and hematocrit in proportion to the severity of dehydration. With increases of 2% in plasma osmolality (24 h dehydration), glucose utilization increased in the supraoptic nuclei and tended to increase in the neural lobe. With further dehydration, glucose utilization also increased in the paraventricular nuclei. These increases were paralleled by depletion of vasopressin and oxytocin contents in the neural lobe and by the enhanced secretion of both hormones into plasma, with a predominant increase of vasopressin. These changes were proportional to the degree of dehydration. With progression of dehydration, decreases in intracellular and extracellular volumes accentuate. Reductions in extracellular volume result in increased angiotensin II (ANG II) formation. Accordingly, glucose utilization in the subfornical organ (SFO), a primary site of ANG II action, increased after 48 and 72 h of dehydration. The median preoptic nucleus, which receives direct inputs from the SFO, also increased glucose utilization at these times. Glucose utilization also increased in the organum vasculosum laminae terminalis, probably in response to the converging inputs from osmoreceptors, volume receptors, and ANG II receptors. Decreases in glucose utilization were observed in the caudal and rostral ventrolateral medulla, perhaps as compensatory responses to decreased extracellular volume to prevent fall in arterial blood pressure.

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