Cyclic nucleotide‐dependent enzyme secretion in the rat lacrimal gland.

Dartt, Darlene A.; Donowitz, Mark; Joshi, Vikram; Mathieu, Romain; Sharp, Geoffrey W. G.

doi:10.1113/jphysiol.1984.sp015297

Cited by 17 publications

(8 citation statements)

References 15 publications

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“…We interpret this to mean that both Ca2+ and cyclic AMP can evoke protein secretion in the rabbit mandibular gland: a similar conclusion has been reached in the case of the rat lacrimal gland (Dartt, Donowitz, Joshi, Mathieu & Sharp, 1984) and rat parotid gland (Baldys-Waligorska, Pour, Moriarty & Dowd, 1987). However, the pattern of secretion differed.…”

Section: Salivar Y Secretion Protein Secretionmentioning

confidence: 74%

Effects of acetylcholine, isoprenaline and forskolin on electrolyte and protein composition of rabbit mandibular saliva.

Case

Howorth

Padfield

1988

The Journal of Physiology

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SUMMARY1. The major purpose of this study was to investigate cellular regulation of the ductal transport processes in salivary glands which act to modify the electrolyte composition of primary saliva and cause it to become hypotonic. This was achieved using an isolated mandibular gland preparation by observing the effect of different stimuli on the electrolyte composition of saliva secreted at the same flow rate, on the assumption that these stimuli do not influence primary saliva composition. The effects of the same stimuli on the volume of primary fluid secretion and on protein secretion were also observed. Proteins were measured in total and as individual components after their separation by high-performance liquid chromatography.2. Acetylcholine was used as a 'Ca2+-mobilizing' agonist (i.e. one which both elevates intracellular Ca21 concentration and activates protein kinase C). Isoprenaline was initially used to elevate intracellular cyclic AMP concentration but was subsequently abandoned in favour of forskolin.3. Acetylcholine was a very potent stimulus of primary fluid secretion. By contrast, isoprenaline and forskolin were essentially without effect, even when superimposed on acetylcholine stimulation. 4. As judged by saliva electrolyte composition, increasing the concentration of acetylcholine enhanced ductal absorption of Na+ and Cl-and secretion of K+ (and presumably HCO3. Forskolin had the opposite effect: when superimposed on submaximal acetylcholine stimulation it caused saliva concentrations of Na+ and Cl-to remain high and K+ low (i.e. it inhibited ductal transport processes). The inhibitory effect of forskolin on ductal transport could be overcome by increasing the concentration of acetylcholine, and vice versa.5. Acetylcholine, isoprenaline and forskolin each increased salivary protein secretion, although the kinetics of secretion differed. The spectrum of proteins secreted in response to the three stimuli was the same. The relative proportions of the individual proteins was influenced by the strength of stimulation (i.e. the proportions at high total protein output differed from those at low total protein output) but not apparently by the nature of the stimulus.6. Thus, the three major secretory processes in the rabbit mandibular salivary gland respond differently to the two major signal transduction mechanisms. For R. M. CASE, A. J. HO WORTH AND P. J. PADFIELD primary fluid secretion, Ca2" is stimulatory and cyclic AMP almost without effect; for ductal transport, Ca2" is stimulatory and cyclic AMP inhibitory; and for protein secretion both Ca2+ and cyclic AMP are stimulatory.

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Section: Salivar Y Secretion Protein Secretionmentioning

confidence: 74%

Effects of acetylcholine, isoprenaline and forskolin on electrolyte and protein composition of rabbit mandibular saliva.

Case

Howorth

Padfield

1988

The Journal of Physiology

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“…Recent studies postulated that there are three intracellular signal-transduction pathways for secretion in lacrimal gland acinar cells: (1) a cholinergic (muscarinic but not nicotinic) pathway that depends on inositol (1,4,5)-triphosphate (IP 3 ) and intracellular calcium-ion concentration ([Ca 2+ ] i ), (2) an α-adrenergic pathway, in which increase of [Ca 2+ ] i is detected, but the IP 3 level is unchanged, and (3) a β-adrenergic as well as VIP pathway that depends on production of cyclic AMP (Dartt et al 1984(Dartt et al , 1988Mauduit et al 1984Mauduit et al , 1987Mauduit et al , 1993Dartt 1989Dartt , 1994Hodges et al 1992). Although these three signaling pathways may be involved in the same acinar cells (Gromada et al 1995), the possibility that there are three different populations of acinar cells cannot be excluded.…”

Section: Introductionmentioning

confidence: 99%

Effects of carbachol and catecholamines on ultrastructure and intracellular calcium-ion dynamics of acinar and myoepithelial cells of lacrimal glands

Satoh

Sano

Habara

et al. 1997

Cell and Tissue Research

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The current study was carried out to investigate autonomic nervous control of secretory functions in the lacrimal gland. To distinguish the difference between the responses to cholinergic and adrenergic agonists in acinar and myoepithelial cells in the lacrimal gland of guinea pigs, the morphological and functional responses to the agonists were examined by electron microscopy and by digital-imaging analysis of the intracellular concentration of Ca2+ ([Ca2+]i) using fluorescent Ca2+-indicators (Fura-2/AM and Indo-1/AM). In the resting state, exocytosis was rare, and the [Ca2+]i in acinar and myoepithelial cells was low (less than 300 nM). Stimulation with carbachol (CCh) induced a rapid rise in [Ca2+]i reaching a peak level followed by gradual decay and an appearance of many exocytotic figures. Approximately 4-8 s after an initial increase of [Ca2+]i, myoepithelial cells commenced contraction. Noradrenaline or adrenaline induced an increase in [Ca2+]i and exocytosis in acinar cells, but caused no [Ca2+]i increase in myoepithelial cells. In a Ca2+-deficient environment, the responses to CCh in myoepithelial cells and those to noradrenaline in acinar cells were inhibited, whereas the responses to CCh in acinar cells remained unchanged. Isoproterenol caused no effect on [Ca2+]i dynamics, although it occasionally induced exocytosis. Different cellular signaling pathways may be involved in the responses in acinar and in myoepithelial cells to different agonists. Lacrimation mechanisms are redundant.

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“…This review describes events which lead to release of Ca2+ from intracellular stores during stimulation and to Ca2+ reuptake into intracellular stores and Ca2+ extrusion from the cell Table 1: Main pathways involved in protein, NaCl and fluid secretion from acinar cells of lacrimal gland (29)(30)(31)(32)(33), salivary glands (11,34) and to regulate cytosolic free Ca2+ concentration in cells of exocrine glands.…”

Section: Introductionmentioning

confidence: 99%

Stimulus-secretion coupling in exocrine glands: The role of inositol-l, 4, 5-trisphosphate calcium and cAMP

Schulz

Streb

Bayerdörffer

et al. 1985

Current Eye Research

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Enzyme, electrolyte and fluid secretion from exocrine glands is stimulated by neurotransmitters and peptide hormones. Whereas for some of these secretagogues calcium is an important intracellular messenger, for others it is cyclic AMP. Regulation of steady state free Ca2+ concentration at rest and at stimulation have been studied in isolated permeabilized acinar cells from pancreas, parotid and lacrimal glands by measuring the free Ca2+ concentration of the surrounding incubation medium with a Ca2+-specific macroelectrode. Ca2+ transport mechanisms have been further characterized in subcellular membrane fractions by measuring 45Ca2+ uptake into membrane vesicles from rough endoplasmic reticulum (RER) and plasma membranes (PM). The data show that the intracellular messenger for secretagogue-induced Ca2+ release from RER is inositol-1,4,5-trisphosphate (IP3) which is produced during stimulation by phospholipase C mediated hydrolysis of phosphatidylinositol-bisphosphate. At rest both Ca2+ uptake into RER and Ca2+ extrusion from the cell is promoted by (Ca2+ + Mg2+)-ATPases with different characteristics in both types of membranes and by a coupled Na+/Ca2+ countertransport in the PM which keep cytosolic free Ca2+ concentration at a low level of approximately 2 - 4 X 10(-7) mol/l. During stimulation the Ca2+ permeability of endoplasmic reticulum membrane increases via IP3 and that of the PM by a yet unknown "receptor-operated" mechanism. These events lead to increase in cytosolic free Ca2+ concentration that is a trigger for enzyme, electrolyte and fluid secretion.

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Cyclic nucleotide‐dependent enzyme secretion in the rat lacrimal gland.

Cited by 17 publications

References 15 publications

Effects of acetylcholine, isoprenaline and forskolin on electrolyte and protein composition of rabbit mandibular saliva.

Effects of acetylcholine, isoprenaline and forskolin on electrolyte and protein composition of rabbit mandibular saliva.

Effects of carbachol and catecholamines on ultrastructure and intracellular calcium-ion dynamics of acinar and myoepithelial cells of lacrimal glands

Stimulus-secretion coupling in exocrine glands: The role of inositol-l, 4, 5-trisphosphate calcium and cAMP

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