Differences between adrenomedullary adrenaline and noradrenaline cells: quantitative electron-microscopic evaluation of their differential cellular association with supporting cells

Ultrastructural histometric evidence for expansion of the sustentacular cell envelope in response to hypersecretion of adrenal chromaffin cells in mice

In our previous immuno-light microscopic study with an antibody for fatty acid binding protein of type 7 or brain type (FABP-7, B-FABP), the adrenomedullary sustentacular cells were revealed to have secondary processes that present faint immunostaining and an ill-defined sheet-like appearance, in addition to the well-recognized primary processes that present distinct immunostaining and a fibrous appearance. The secondary processes were regarded as corresponding to known ultrastructural profiles of sustentacular cells with a thickness of less than 0.2 µm (the resolution limit of light microscopy), and the processes were considered to be largely responsible for enveloping chromaffin cells. Due to those findings, the present immuno-electron microscopic study was performed to determine whether the secondary processes change the extent of their envelope for chromaffin cells under the intense secretion induced by water immersion-restraint stress. To achieve this, we focused on immunopositive ultrastructural profiles with a thickness of less than 0.2 µm. The measured lengths of the immunopositive profiles in the specimens from stressed mice were found to be significantly larger than those in specimens from normal mice, indicating an increase in the extent of the envelope of the sheet-like processes for the chromaffin cells. Thus, confining our measurements to the secondary process profiles, not the entire cell profiles, proved to be a key factor in the detection-for the first time-of the change in size of the sustentacular cell envelope upon changes in the secretory activity of enveloped chromaffin cells. The possible functional significance of this change in size is discussed here.

An electron microscopic study on nerve endings on adrenomedullary adrenaline cells in golden hamsters: position, size and changes due to pinealectomy

Effects of sham-pinealectomy and pinealectomy on preganglionic nerve endings on adrenomedullary adrenaline cells were investigated electron microscopically. Adult male golden hamsters from the normal, sham-pinealectomy and pinealectomy groups maintained under 24 h light-dark cycle and constant temperature were used at 28 days after surgery. From conventional electron microscopic specimens, montage photographs made of the adrenaline cell region at a magnification of x 11,000 were used for qualitative and quantitative electron microscopic analyses in 14 animals in each experimental group. The preganglionic nerve endings were localized mainly in the following three sites: the basal lamina part, the follicular lumen-junctional intercellular part, and the adrenaline cell-invaginated part. In the latter two parts, nerve endings and fibers had no envelope frequently, and in the former two parts, nerve endings sometimes showed the invagination complex. The frequency of nerve endings was highest in the follicular lumen-intercellular part, next highest in the basal lamina part and lowest in the A cell-invaginated part. The frequency of nerve endings in the basal lamina part was lower in the pinealectomy group than in the sham-pinealectomy group (P < 0.021), and those in the other two parts showed opposite changes, more evidently in the A cell-invaginated part. Nerve ending profiles in the adrenaline cell-invaginated part--which displayed a more rounded shape--increased in size in the pinealectomy group (longer diameter: P < 0.04; shorter diameter: P < 0.05). In conclusion, preganglionic nerve endings in the adrenal medulla of the golden hamster show differential morphological changes following PX depending on the intracellular part of A cells.

D-aspartic acid localization during postnatal development of rat adrenal gland

Developmental changes in cellular localization of D-aspartic acid (D-Asp) were investigated in rat adrenal gland with polyclonal anti-D-Asp antibody. At 1 and 3 weeks of age, immunoreactivity (IR) toward this amino acid was intense in the cytoplasm of cells in the zona fasciculata (ZF) and zona reticularis (ZR) of the adrenal cortex but was less so in the zona glomerulosa (ZG). Conversely at 8 weeks of age, intense IR was observed in the ZG and less in the ZF and ZR. In the adrenal medulla, IR was evident in large clusters of cells which were identified as adrenaline-storing cells. The emergence of D-Asp in specific types of cells at distinct periods of development of rat adrenal gland suggests that this amino acid may have a physiological role in the maturation of the organ.

Similarities and differences in supporting and chromaffin cells in the mammalian adrenal medullae: an immunohistochemical study

BACKGROUND

The adrenal medulla is a typical paraganglion, having the same origin as the sympathetic ganglia, and contains at least two types of parenchymal cells: chromaffin cells and supporting cells. We previously reported that the extent of cellular association of chromaffin cells with supporting cells was remarkably higher in noradrenaline (NA)-than in adrenaline (A)-cell regions in the adrenal medullae of the rat and pig.

METHODS

Cryostat sections of adrenal medullae of nine mammalian species fixed with Zamboni fluid for 24 h were immunostained by ABC methods using antisera to S-100 protein and PNMT.

RESULTS

The distribution patterns of A and NA cells in the adrenal medullae were classified into four types. In the chipmunk and rabbit, adrenomedullary chromaffin cells consisted of A cells. S-100-immunoreactive cells were present more frequently in NA- than in A-cell regions in seven species (rat, golden hamster, cat, dog, pig, ox, and horse). These cells sent out cytoplasmic processes and formed a network by immunoreactive elements among NA cells. The cell-association patterns of S-100-positive cells with NA cell were classified into three types. In A-cell regions, only a few S-100-positive cells were seen in most of the species, although the frequency of S-100-labeled cells were exceptionally high in the horse.

CONCLUSIONS

The close association of supporting cells with NA cells was commonly found in the adrenal medulla in many mammalian species, irrespective of the proportions and distribution patterns of A cells and NA cells. On the other hand, species differences existed in details of the cellular association between supporting cells and NA cells.

Cyclic GMP-dependent protein kinase activation mediates inhibition of catecholamines secretion and Ca2+ influx in bovine chromaffin cells

The effects of the membrane-permeable cGMP analogue, 8-bromoguanosine 3':5'-cyclic monophosphate on acetylcholine-evoked catecholamine secretion and cytosolic calcium increases were studied in chromaffin cells from the bovine adrenal gland. Preincubation with 100 microM 8-bromoguanosine 3':5'-cyclic monophosphate during 10 and 30 min decreased the acetylcholine-evoked catecholamine release by 16 +/- 3% and 27 /+- 5%, respectively. The cytosolic calcium increases triggered by acetylcholine and 30 mM KCl were also inhibited by 30 min of preincubation with this compound by 27 +/- 4 and 34 /+- 12%, respectively. Changes in membrane potential induced by acetylcholine and KCl were not affected by preincubation with 8-bromoguanosine 3':5'-cyclic monophosphate. The cyclic GMP-dependent protein kinase inhibitor N-[2-(methylamino)ethyl]-5-isoquinoline sulfonamide dihydrochloride-at l micron abolished the inhibitory effect of 8-bromoguanosine 3':5'-cyclic monophosphate on acetylcholine-evoked calcium increase. By contrast, a potent and selective inhibitor against cyclic AMP-dependent protein kinase, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide did not block the 8-bromoguanosine 3':5'-cyclic monophosphate effect. Additionally, 8-bromoguanosine 3':5'-cyclic monophosphate stimulated histone F2b phosphorylation by a partial purified cGMP-dependent protein kinase from chromaffin cells. The extent of histone phosphorylation was reduced by N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride and 8-(4-chlorophenylthio)-guanosine 3':5'-cyclic monophosphorothioate, Rp-isomer, a specific inhibitor against cyclic GMP-dependent protein kinase, whereas it was not modified by N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline sulfonamide. The results suggest that the inhibitory effects of 8-bromoguanosine 3':5' cyclic monophosphate on chromaffin cells are mediated through the activation of cGMP-dependent protein kinase.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences between adrenaline and noradrenaline cells in cellular association with supporting cells in the adrenal medulla of the pig: an immunohistochemical study

Location and morphology of glial supporting cells in the pig adrenal medulla were examined immunohistochemically by the ABC method using antibody to S-100 protein. In noradrenaline (NA)-cell regions, S-100-positive cells were located in both marginal and internal portions of the parenchyma, extending fine cytoplasmic processes between NA cells and/or enveloping large surface areas of NA cells. In adrenaline (A)-cell regions, S-100-positive cells were present less frequently than in NA-cell regions, mostly in the marginal portion of the parenchyma. It is surmised that differences between A cells and NA cells in cellular association with supporting cells reflect those in biological characteristics.