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At least 19 recordsLinked to original sources
PubMed1991

Microscopic anatomy of the baboon (Papio hamadryas) adrenal medulla.

Adrenal medullas of 2 baboons perfused with formaldehyde/glutaraldehyde and tannic acid were studied by light and electron microscopy. Tissues were postfixed in OsO4. This procedure allows identification of noradrenaline cells on the basis of a selective reaction of glutaraldehyde with noradrenaline vesicles. As positive control for noradrenaline cells, similarly treated mouse adrenal medullas were also examined. Light microscopic examination of thick sections of baboon medullas did not show noradrenaline cells. In contrast, mouse adrenal medullas showed noradrenaline cells scattered in small groups among the much lighter adrenaline cells. By electron microscopy no noradrenaline cells were seen in the baboon medulla while mouse adrenal medullas showed noradrenaline cells with vesicles possessing exceedingly dense cores and light spaces within their limiting membranes. Otherwise, the majority of the baboon chromaffin cells showed chromaffin vesicles which were round or elongated, 150-520 nm in diameter, and heterogenous in electron density. Cytoplasmic densities were occasionally seen attached to the inner aspect of the plasmalemma, particularly along areas close to blood capillaries. These densities could be chromaffin vesicles in the process of exocytosis. This is the first report of exocytotic profiles in a primate medulla. Occasional small vesicle-containing cells also were present. The vast majority of their vesicles were electron dense. Several possible alternatives for the varied catecholamine vesicular osmiophilia, were discussed. It was suggested that this could be attributed to varied concentration of noradrenaline and adrenaline neurohormones among the vesicle population.

Adrenal Medulla↗
PubMed1991

Decreased levels of [Met]enkephalin, neuropeptide Y, substance P, and vasoactive intestinal peptide in parkinsonian adrenal medulla.

Adrenal medullary tissue was collected from parkinsonian patients at autopsy and at the time of autologous transplantation of the adrenal medulla to the caudate nucleus, and from nonparkinsonian patients at autopsy and during nephrectomy. Levels of the following neuropeptides were measured by radioimmunoassay in samples of the medullary tissue: neuropeptide Y (NPY), substance P (SP), [Met]enkephalin ([Met]ENK), vasoactive intestinal peptide (VIP), peptide YY, and bombesin-like immunoreactivity. Regression analysis was used to establish a relationship between patient age, time to organ harvest, and peptide levels in nonparkinsonian tissue. Levels of [Met]ENK, VIP, NPY, and SP were significantly lower in parkinsonian adrenal medullae than that predicted from the control group. These results suggest that the adrenal medulla of a parkinsonian patient is severely compromised, either by the disease process itself or by the antiparkinsonian medications used to treat the symptoms of the disease.

Adrenal Medulla↗
PubMed1986

Ontogeny of enkephalin and catecholamine-synthesizing enzymes in the primate fetal adrenal medulla.

Adrenal medullary cells in adult primates contain catecholamines and several neuropeptides. Among these peptides are several products of the three opiate precursor proteins: proenkephalin, prodynorphin, and proopiomelanocortin. We used immunocytochemistry to study the ontogeny of leu-enkephalin and the catecholamine-synthesizing enzymes dopamine beta-hydroxylase and phenylethanolamine N-methyltransferase in adjacent sections of 14 fetal rhesus and 31 fetal human adrenal glands. The adrenal medulla of a 24-week-old human fetus as well as medullas of 11 134- to 172-day-old rhesus fetuses were immunopositive with all 3 antisera employed. Furthermore, in thin serial sections of these glands, dopamine beta-hydroxylase, phenylethanolamine N-methyltransferase, and leu-enkephalin appeared to be colocalized in the same cells of the adrenal medulla. Twenty-six adrenals from fetuses 15-26 weeks stained lightly with one or more of the antisera. Dopamine beta-hydroxylase could be detected at 15 weeks, followed by leu-enkephalin and phenylethanolamine N-methyltransferase at 18-19 weeks. The role of the enkephalins during fetal life or in the adaptation to extrauterine life is not yet clear. In adults, enkephalins are cosecreted with catecholamines in response to stress. Our results suggest that the fetal adrenal may be capable of cosecretion of catecholamines and enkephalins, at least by the end of the second trimester of gestation.

Adrenal Medulla↗
PubMed1999

Vitamin D3-induced proliferative lesions in the rat adrenal medulla.

Adrenal medullary hyperplasia and pheochromocytomas are induced in rats by a variety of non-genotoxic agents, and we have hypothesized that these agents induce lesions indirectly by stimulating chromaffin cell proliferation. Vitamin D3, which has not been previously associated with adrenal medullary proliferative lesions, is the most potent in vivo stimulus to chromaffin cell proliferation yet identified. The present investigation utilized the vitamin D3 model to prospectively test the relationship between mitogenicity and focal proliferative lesions in the adrenal medulla and to determine early events in the pathogenesis of these lesions. Charles River Crl:CD BR rats were treated with 0; 5000; 10,000; or 20,000 IU/kg/day of vitamin D3 in corn oil (5 ml/kg) by oral intubation. Rats were killed after 4, 8, 12, or 26 weeks of treatment, following a final week of labeling with bromodeoxyuridine (BrdU) using a mini-pump. Adrenal sections were double-stained for BrdU and phenylethanolamine-N-methyl transferase (PNMT) to discriminate epinephrine (E) from norepinephrine (NE) cells or for vesicular acetylcholine transporter (VAchT) to identify cholinergic nerve endings. Vitamin D3 caused a 4-5-fold increase in BrdU labeling at week 4, diminishing to a 2-fold increase by week 26. An initial preponderance of labeled E cells gave way to a preponderance of labeled NE cells. By week 26, 17/19 (89%) animals receiving the 2 highest doses of vitamin D3 had focal adrenal medullary proliferative lesions, in contrast to an absence of lesions in control rats. The lesions encompassed a spectrum including BrdU-labeled "hot spots" not readily visible on H and E sections, hyperplastic nodules, and pheochromocytomas. Lesions were usually multicentric, bilateral, and peripheral in location, and almost all were PNMT-negative. The lesions were not cholinergically innervated, suggesting autonomous proliferation. Hot spots, hyperplastic nodules, and pheochromocytomas appear to represent a continuum rather than separate entities. Their development might involve selective responses of chromaffin cell subsets to mitogenic signals, influenced by both innervation and corticomedullary interactions. A number of non-genotoxic compounds that induce pheochromocytomas in rats are known to affect calcium homeostasis. The results of this study provide further evidence to support the hypothesis that altered calcium homeostasis is indirectly involved in the pathogenesis of pheochromocytomas, via effects on chromaffin cell proliferation.

Administration, Oral↗
PubMed1985

Neuronotrophic and neurite-promoting factors: effects on early postnatal chromaffin cells from rat adrenal medulla.

Adrenal chromaffin cells from early postnatal rats maintained in culture have previously been shown to grow neuritic processes and survive better in the presence of nerve growth factor (NGF). In the present study we have quantitated the effects on chromaffin cell (postnatal day (D) 8) survival and neurite outgrowth of: NGF, ciliary neuronotrophic factor (CNTF), activities contained in various types of conditioned media (CM), and various substrata (laminin, fibronectin and polyornithine-binding neurite-promoting factor from RN 22 Schwannoma cells - PNPF). At saturating concentrations CNTF (50 ng/ml) and C6 glioma cell CM, (50-fold concentrated) supported survival over the 4-day culture period of all the chromaffin cells present in culture 2 h after seeding. NGF (50 ng/ml) and the non-concentrated CMs from primary Schwann cell and astrocytes as well as Schwannoma and C6 glioma cell cultures, achieved the maintenance of only about half the number of cells above the baseline survival as compared to CNTF and the concentrated C6-CM. These results are compatible with two subsets of D8 chromaffin cells, one only supported by CNTF and the concentrated CM and the other supported by either NGF or CNTF. Either NGF or CNTF elicited neurite outgrowth from 15-20% of the surviving cells. Combination of maximal doses of NGF and CNTF caused a small increase in neurite recruitment beyond that elicited by either factor alone. Low doses of CNTF added to the effect of NGF, shifting the NGF titration curve by about 4-fold. Neurite outgrowth was also induced by the concentrated, but not the unconcentrated C6-CM. Laminin, fibronectin and PNPF did not affect the fibronectin and PNPF did not affect the recruitment of neurites as compared to a polyornithine substratum unless the cultures were supplemented with a neuronotrophic factor and carried for 7 days. However, even before showing effects on neurite recruitment these substrata affected various neuritic performances, such as length, neurite numbers and endings per cell.

Adrenal Medulla↗
PubMed1980

In vitro studies on a two-pool stage of adrenaline and noradrenaline in granule material from bovine adrenal medulla.

Adrenal medullary granules were isolated by millipore filtration according to Poisner & Trifaró (1967) and then lysed in deionized water. In a perfusion system the influence of concentration of pH was studied on the uptake of biogenic amines (PhEA, TA, DA, NA, A, Arch and Hi) and sodium ions by lysed and by dialyzed material. The results suggest a two-pool storage of A and NA in the granules. A minor pool with cation exchanger properties binds unselectively organic (biogenic amines) and inorganic cations with a Umax of 400-500 nmol/mg granules dry-weight. This minor pool (pool 1) was fully charged at amine concentrations greater than 10 mM. A larger pool binds selectively A and NA--possibly stereospecifically L-NA and L-A--with a Umax approximately 1500 nmol/mg granules. This larger pool (pool 2) required A and NA concentrations approximately 200-300 mM for maximal filling. In pool 2 CA+ ions are assumed to be electrostatically linked to carboxyl groups, which become available as hypothetical COO----+H3N salt bridges are successively forced open by increasing CA concentrations (greater than 10-30 mM). ATP- ions become attached to the concomitantly unmasked +NH3 groups.

Acetylcholine↗
PubMed1978

Certain cytologic features of the porcine adrenal medulla.

Adrenal glands were collected from pigs of various ages under general anesthesia. Glutaraldehyde-fixed medullary tissue was postfixed with OsO4 for electron microscopy and with potassium dichromate or potassium iodate for light microscopy. Columnar epinephrine (E) cells formed cords between wide sinusoidal capillaries at the corticomedullary junction and were arranged in palisade fashion along the central vein and its major tributaries. The E cells usually were polarized, with the nuclei located away from the sinusoidal capillaries. Clusters of polygonal norepinephrine (NE) cells formed large central aggregates surrounded by E cells. Granulated vesicles were the predominant cytoplasmic feature of both E and NE cells. Round or oval E granules were bounded by a crenated membrane separated from the granule by a clear halo. The more electron-dense, elongate NE granules were bounded by a closely apposed, smooth membrane. The average longest granule axis was 270 nm for E granules and 305 nm for NE granules. Many cytoplasmic organelles were congregated in a granule-free paranuclear zone, which contained a prominent Golgi complex. Thin nonmyelinated nerve fibers (singly or in small groups) were interposed between the E and NE cells. Nerve fibers often were located close to the nucleus in a depression of the cell surface and often were wrapped by thin E or NE cell processes. The medulla of newborn pigs was composed predominantly or exclusively of NE cells. In both adults and pigs, E or NE cell cords radiated through the cortex toward the capsule, and isolated clusters of E or NE cells frequently were found in the capsule or zona glomerulosa.

Adrenal Medulla↗
PubMed1998

TrkB and neurotrophin-4 are important for development and maintenance of sympathetic preganglionic neurons innervating the adrenal medulla.

The adrenal medulla receives its major presynaptic input from sympathetic preganglionic neurons that are located in the intermediolateral (IML) column of the thoracic spinal cord. The neurotrophic factor concept would predict that these IML neurons receive trophic support from chromaffin cells in the adrenal medulla. We show here that adrenal chromaffin cells in the adult rat store neurotrophin (NT)-4, but do not synthesize or store detectable levels of BDNF or NT-3, respectively. Preganglionic neurons to the adrenal medulla identified by retrograde tracing with fast blue or Fluoro-Gold (FG) express TrkB mRNA. After unilateral destruction of the adrenal medulla, 24% of IML neurons, i.e., all neurons that are preganglionic to the adrenal medulla in spinal cord segments T7-T10, disappear. Administration of NT-4 in gelfoams (6 microgram) implanted into the medullectomized adrenal gland rescued all preganglionic neurons as evidenced by their presence after 4 weeks. NT-3 and cytochrome C were not effective. The action of NT-4 is accompanied by massive sprouting of axons in the vicinity of the NT-4 source as monitored by staining for acetylcholinesterase and synaptophysin immunoreactivity, suggesting that NT-4 may enlarge the terminal field of preganglionic nerves and enhance their access to trophic factors. Analysis of TrkB-deficient mice revealed degenerative changes in axon terminals on chromaffin cells. Furthermore, numbers of FG-labeled IML neurons in spinal cord segments T7-T10 of NT-4-deficient adult mice were significantly reduced. These data are consistent with the notion that NT-4 from chromaffin cells operates through TrkB receptors to regulate development and maintenance of the preganglionic innervation of the adrenal medulla.

Adrenal Medulla↗
PubMed2005

A new focus on interoceptive properties of adrenal medulla.

The adrenal medulla is an important part of the sympathoadrenal system. Chromaffin cells of the adrenal medulla respond to a broad spectrum of stressful situations by releasing epinephrine and norepinephrine. Originally, it was accepted that this response is controlled exclusively by central nervous system structures. However, it was also demonstrated that a surgically denervated adrenal medulla can respond directly by secreting epinephrine and norepinephrine during an imbalance of internal environment (hypoglycemia, asphyxia). Published data had documented the innervation of the adrenal medulla by sensory neurons of spinal dorsal root ganglia. In addition, recent data showed that ganglion cells of the adrenal medulla project ascending axons. These data suggested potential transmission of information from the adrenal medulla to the central nervous system regarding metabolic changes in the blood. This paper presents an overview of possible involvement of adrenal medullary chromaffin cells in the detection of changes in the internal environment and in the transmission of this information to the central nervous system.

Adrenal Medulla↗