Biochemical analysis of catecholamines in small intensely fluorescent (SIF) cell clusters of the rat superior cervical ganglion.

The microlaser technique of isolating small cell clusters has been applied to groups of small intensely fluorescent (SIF) cells in rat superior cervical ganglion. Alternate cryostat sections were either incubated in glyoxylic acid monohydrate or freeze-dried. SIF cell clusters, recognized by glyoxylic acid-induced fluorescence, were re-identified in the consecutive freeze-dried section through dark-field microscopy. Three clusters were dissected with a BTG microlaser unit and collected for biochemical assay. The catecholamine content of the specimens was measured by gas chromatography/mass fragmentography, using 3 deuterated catecholamines as an internal standard and calibration curves of each catecholamine. The findings indicate the presence of these 3 catecholamines in rat SIF cell clusters in a varying amount: in probes, each consisting of 5 cell clusters, the content of norepinephrine averaged approximately 7.3 pmol, of epinephrine below 1 pmol, and of dopamine from below 1 pmol to 14.6 pmol.

Immunofluorescence of dopamine-beta-hydroxylase in small intensely fluorescent cells of human sympathetic ganglia.

Thoracic and lumbar sympathetic ganglia of human males were investigated using a method for the consecutive demonstration of catecholamines and catecholamine synthesizing enzymes in fluorescence microscopy. In the thoracic ganglion, a minor population of small intensely fluorescent (SIF) cells, identified by glyoxylic-acid-induced fluorescence, exhibited positive indirect immunofluorescence after incubation with antibody to dopamine-beta-hydroxylase (DBH). SIF cells in the lumbar ganglion exclusively stained DBH-negative. The findings indicate the presence of two SIF cell populations in the thoracic ganglia of the human sympathetic trunk, one containing dopamine and the other containing norepinephrine and/or epinephrine. In lumbar ganglia, only dopamine-storing SIF cells appear to be present.

Immunofluorescent and biochemical studies on dopamine-beta-hydroxylase and catecholamines in SIF cells of the superior cervical ganglion.

Small intensely fluorescent (SIF) cells in the superior cervical ganglion (SCG) of various laboratory animals were investigated: 1. Applying a combined method for successive demonstration of glyoxylic acid-induced catecholamine fluorescence and of indirect FITC-labelled antibody to dopamine-beta-hydroxylase (DBH) in the rat SCG very few SIF cell clusters stained DBH-positive. The majority of cell clusters was observed to be DBH-negative. In the guinea pig SCG, DBH-negative SIF cells were intermingled between DBH-positive SIF cells within large clusters. In the SCG of Syrian hamster, mouse C57BT10, desert mouse and rabbit all SIF-cells revealed the presence of DBH and thus of norepinephrine (NE) or epinephrine (E). 2. Gaschromatographic/mass fragmentographic measurements of catecholamines in SIF cell clusters of the rat SCG, which were separated frm the surrounding principal neurons by microlaser, disclosed a considerable concentration of E, and also a very low concentration of NE, within SIF cells. The results corroborate the hypothesis of a SIF cell heterogenity within sympathetic ganglia. They may also be discussed on the basis of a functional dualism of one SIF cell population.

Catecholamines in paraganglionic cells of the rat superior cervical ganglion: functional aspects.

In the rat SCG two types of paraganglionic cells have been identified immunohistochemically in a ratio of about 5% DBH-positive to 95% DBH-negative cells. Measurements of CAs in SIF cell clusters separated from principal neurons with the microlaser and using the technique of quantitative mass fragmentography disclosed the presence of E within paraganglionic cells, thus confirming the proposal that, besides DA, E also is stored in most cells. Following immobilization of adult rats, the majority of SIF cells revealed a time-dependent loss of formaldehyde-induced fluorescence intensity that could be ultrastructurally correlated with an increasing degranulation of small granule-containing perikarya, presumed to store DA and E. Similar results were obtained in type I cells of the rat carotid body and adrenal medullary cells, thus suggesting a mutual endocrine function. An additional interneuronal mode of modulation is assumed, since degranulated cells are capable of displaying efferent synaptic contact with postganglionic neurons. A minor cell population, storing granular vesicles similar to those in the NE-containing cells of the adrenal medulla, did not respond with degranulation to functional strain of the vegetative nervous system. Our results strongly corroborate the hypothesis that a functional dualism exists: Most paraganglionic cells can act as an interneuron and as an endocrine cell.