Salivary Secretion of Highly Concentrated Chromogranin a in Response to Noradrenaline and Acetylcholine in Isolated and Perfused Rat Submandibular Glands

Abstract

Chromogranin A (CgA) is a member of a family of highly acidic proteins, chromogranins, which are co-stored in the adrenergic neurons and paraneurons and co-released with adrenaline and noradrenaline (NAd) in response to adequate stimulation. The present study provides novel evidence that CgA-like immunoreactivity (IR) is stored in the exocrine cells in the granular convoluted tubule, and is secreted into saliva by stimulation with NAd and acetylcholine (ACh) in the isolated and perfused rat submandibular gland. NAd at 1 microM produced maximum secretion of CgA-like IR (<< 0.9 mM) and a marked increase in salivary flow. Further increases in NAd concentration (10 or 100 microM) yielded concentration-dependent decreases in both responses. ACh at 1 microM produced maximum salivary flow and a slight elevation of CgA-like IR secretion (6 microM); 100 microM ACh decreased the salivary flow but increased the CgA-like IR secretion (0.6 mM). Electron microscopic examination showed vigorous compound exocytosis of secretory granules in the cells of the granular convoluted tubule when the submandibular gland was stimulated with 1 microM NAd. These results provide an experimental basis for the view that the salivary CgA-like IR secretion may be a sensitive and quantitative index of the activity of the sympathetic nervous system innervating the gland.

Variation of Chromogranin a Serumlevels After Radical Retropubic Prostatectomy for Prostate Adenocarcinoma

“…Some authors [11,14] showed that plasmin, as a protease, cleaves CgA to generate a bioactive fragment that inhibits nicotinic-mediated catecholamine release, providing a negative feedback mechanism for regulating catecholamine responses during stress. Similarly, other authors [16] showed that CgA levels increase in response to a large amplitude physical stimulation in adult subjects and are related to catecholamine levels.…”

Oral administration of Cimicifuga racemosa extract attenuates psychological and physiological stress responses

“…It belongs to a family of highly acidic proteins, which are co-stored and co-released with catecholamine in the adrenal medulla (3,57). CgA was shown to be a valuable indicator of sympathoadrenal activity (55), and is a possible alternative to the measurement of plasma catecholamine concentrations (23). Moreover, salivary CgA secretion might be an index for activated sympatho-adrenal activity in the stress response (33,59).…”

Measurement of chromogranin A in porcine saliva: validation of a time-resolved immunofluorometric assay and evaluation of its application as a marker of acute stress

“…Its liberation from the salivary gland is mediated by the secretion of catecholamines (Kanno et al, 1999), and it has been postulated that the measurement of salivary CgA could be used as a sensitive and reliable quantitative tool for monitoring the activity of the sympathetic nervous system, which constitutes the initial alarm in stress response Nakane et al, 1998). Although the physiological role of CgA is still under investigation, the accumulated evidence provides convincing support for a role of CgA in counteracting sympathetic activity (Gallina et al, 2011).…”