Possible role of cyclic GMP in stimulus-secretion coupling by salt gland of the duck

Stewart, David J.; Sax, Julian; Funk, R.; Sen, Amar K.

doi:10.1152/ajpcell.1979.237.5.c200

Cited by 16 publications

(10 citation statements)

References 21 publications

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“…The consumption of 02 was considerably stimulated by methacholine, with maximal effect at 0-2 mm (not shown). Our measurements in the Tris-phosphate Ringer solution show a similar concentration dependence to those of Stewart et al (1979) series of experiments to another. On occasion, there was a tendency for the control rate to decline slightly while the stimulated respiration remained constant for 2-3 observation periods before itself declining; in this case the degree of stimulation showed a maximum after 25-35 min, as in Fig.…”

Section: Effects Of Methacholine On Salt-gland Slicessupporting

confidence: 85%

“…In further experiments we compared the intracellular ionic contents of slices incubated for 120 min at 1°C and 60 min at 38 'C in Ringer solutions in which either 25 mM-HC03-plus 2 mM-phosphate ( Stewart et al (1979) series of experiments to another. On occasion, there was a tendency for the control rate to decline slightly while the stimulated respiration remained constant for 2-3 observation periods before itself declining; in this case the degree of stimulation showed a maximum after 25-35 min, as in Fig.…”

Section: Effects Of Methacholine and Ouabainmentioning

confidence: 99%

“…Precise definition of the underlying ion-transport mechanisms is hindered for want of a tissue preparation in which the polarity of trans-epithelial ion movements can be distinguished in vitro, but useful information can be obtained from studies of tissue slices or isolated cells. In particular, observations have been made of the net or unidirectional movements of ions between the cells and their medium (van Rossum, 1964(van Rossum, , 1966Peaker, 1971;Hootman & Ernst, 1981), and of the altered metabolic activity induced by cholinergic agents (Borut & Schmidt-Nielsen, 1963;Hokin, 1966;van Rossum, 1968; Stewart, Sax, Funk & Sen, 1979;Hootman & Ernst, 1980). In the latter case, it is necessary to assume that the cholinergic stimulation of metabolism is closely related to the stimulation of secretion.…”

Section: Introductionmentioning

confidence: 99%

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Ions and energy metabolism in duck salt‐gland: possible role of furosemide‐sensitive co‐transport of sodium and chloride

Ernst

Rossum

1982

The Journal of Physiology

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SUMMARY1. The effects of methacholine on net ionic movements and energy metabolism of the avian salt-gland have been studied, using slices of glands taken from salt-adapted Pekin ducks. The slices were equilibrated with media and drugs for 120 min at 1 0C before the experimental incubation at 38 'C.2. During incubation at 38 'C the slices accumulated K+ and lost Na+ and Cl-. In the presence of methacholine, they retained more Na+ and Cl-and accumulated less K+, the maximal effects being given by 05-1 0 mM-methacholine. Similar results were obtained whether the medium contained 10 mM-Tris (used in most experiments) or 25 mM-HC03-as the major buffer.3. The higher final levels of cell Na+ and Cl-induced by methacholine were not seen when furosemide (1 mM) was also present. Methacholine did not induce a higher level of cell Na+ when medium Cl-was replaced by I-, NO3-or S042-, and did not induce a higher Cl-content when medium Na+ was replaced by choline or Li+. The fall of K+ accumulation caused by methacholine was also prevented by furosemide or by replacing C1-in the medium with other anions. The anion-transport inhibitors, SCN-(up to 10 mM) and 4,4'-diisothiocyano-2,2'-disulphonic acid stilbene (DIDS) (up to 2 mM) did not prevent the effects of methacholine.4. Methacholine stimulated respiration and lowered the slice ATP contents, and these effects were both prevented by ouabain or furosemide. Ouabain, but not furosemide, also reduced the basal (i.e. in the absence of methacholine) rate of respiration and raised the ATP level. SCN-and DIDS had no effect on basal or stimulated respiration or on ATP contents.5. The respiratory stimulation and fall of ATP induced by methacholine were totally prevented if medium Na+ was replaced by choline. Replacement of Nat by Li+ caused some stimulation of basal respiration; it also permitted some loss of ATP in the presence of methacholine, but the loss was smaller than that seen in the normal Na+ medium.6. The respiratory stimulation and fall of ATP induced by methacholine were prevented if medium Cl-was replaced by S042-. The effects of methacholine were partially blocked when N03-replaced Cl-. S. A. ERNST AND G. D. V. VAN ROSSUM 7. The results are consistent with the stimulation by methacholine of a furosemidesensitive, coupled entry of Na+ and Cl-into the cells, associated with a loss of K+. This would result in a stimulation of Na+ extrusion by the ouabain-sensitive transport system for Na+ and K+ with increased consumption of ATP.

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Section: Effects Of Methacholine On Salt-gland Slicessupporting

confidence: 85%

Section: Effects Of Methacholine and Ouabainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ions and energy metabolism in duck salt‐gland: possible role of furosemide‐sensitive co‐transport of sodium and chloride

Ernst

Rossum

1982

The Journal of Physiology

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“…Moreover, avian salt gland secretory cells also possess large numbers of muscarinic ACh (mACh) receptors, which when activated, initiate a multitude of secretion-related processes within the cell (e.g. Borut and Schmidt-Nielsen, 1963;Hootman and Ernst, 1981;Hootman and Ernst, 1982;Stewart et al, 1979;van Rossum and Ernst, 1978). In addition, saltwater acclimation results in a 3-fold increase in the number of mACh receptors on duck salt gland secretory cells (Hootman and Ernst, 1981), suggesting that ACh plays a large, multifaceted role in regulating the secretory process.…”

Section: Discussionmentioning

confidence: 99%

Functional and morphological plasticity of crocodile (Crocodylus porosus) salt glands

Cramp

Meyer

Sparks

et al. 2008

Journal of Experimental Biology

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SUMMARYThe estuarine crocodile, Crocodylus porosus, inhabits both freshwater and hypersaline waterways and maintains ionic homeostasis by excreting excess sodium and chloride ions via lingual salt glands. In the present study, we sought to investigate the phenotypic plasticity, both morphological and functional, in the lingual salt glands of the estuarine crocodile associated with chronic exposure to freshwater (FW) and saltwater (SW) environments. Examination of haematological parameters indicated that there were no long-term disruptions to ionic homeostasis with prolonged exposure to SW. Maximal secretory rates from the salt glands of SW-acclimated animals (100.8±14.7·mol·100·g ). There were no differences in the mass-specific metabolic rate of salt gland tissue slices from FW-and SW-acclimated animals (558.9±49.6 and 527.3±142.8·l·O 2 ·g -1 ·h -1 , respectively). Stimulation of the tissue slices from SW-acclimated animals by methacholine resulted in a 33% increase in oxygen consumption rate. There was no significant increase in the metabolic rate of tissues from FW-acclimated animals in response to methacholine. Morphologically, the secretory cells from the salt glands of SW-acclimated animals were larger than those of FW-acclimated animals. In addition, there were significantly more mitochondria per unit volume in secretory tissue from SW-acclimated animals. The results from this study demonstrate that the salt glands of C. porosus are phenotypically plastic, both morphologically and functionally and acclimate to changes in environmental salinity.

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“…It is unclear why an increase in RNA synthesis could not be detected under in vitro conditions, since previous studies indicate that total RNA content of the salt gland increases following saIt stress (Holmes and Stewart, 1968). Although some cellular metabolic activities of the salt gland may require continuous cholinergic stimulation (Stewart et al, 1979;Stewart and Sen, 1981;Ernst and Van Rossum, 1982), we found no effect by cholinergic agonists on in uitro RNA synthetic rates in either nonstressed or stressed salt-gland slices (data not shown). In contrast to the in vitro studies, however, the in vivo rates found in the present study are consistent with earlier observations and appear to reflect true biosynthetic events.…”

Section: Discussionmentioning

confidence: 58%

Plasma membrane biogenesis in the avian salt gland: A biochemical and quantitative electron microscopic autoradiographic study

et al. 1985

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The avian salt gland provides an ideal system for the study of plasma membrane (PM) biogenesis. Feeding ducklings 1% sodium chloride (salt stress) induces the secretory cells of the gland to synthesize large amounts of PM, which forms an extensive basolateral PM domain after 7-9 days of treatment. In the present study, the initial biosynthetic events following salt stress were investigated. In vivo studies using 3H-uridine indicated that increased rates of RNA synthesis could be detected by 2 hr after the beginning of salt stress and continued through at least 12 hr. Under in vitro conditions, increased rates of protein and glycoprotein synthesis (as monitored by 3H-leucine and 3H-fucose incorporation, respectively) were also detected after 2 hr and continued through 7-9 days. Increased levels of Na,K-ATPase, a specific secretory cell PM marker, were detected after 8 hr of treatment as monitored by specific activity and 3H-ouabain binding. Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis coupled with fluorography indicated that both 3H-leucine and 3H-fucose were incorporated into partially purified preparations of Na,K-ATPase isolated after 12 hr. Light microscopic autoradiographic analysis of pulse-chase experiments indicated that in secretory cells of 12-hr salt-stressed glands, 3H-leucine- and 3H-fucose-labelled products reached the cell periphery by 1-2 hr after the initial pulse. The incorporation of both tritiated precursors was predominantly associated with the secretory cells. Quantitative electron microscopic autoradiography indicated that 3H-leucine is initially taken up by elements of the rough endoplasmic reticulum (RER) and cytoplasm (5 min postpulse), subsequently transported to and concentrated within components of the Golgi apparatus (10 min of chase), and ultimately incorporated into all domains of the plasma membrane of secretory cells by 1-2 hr of chase. The data is consistent with a flow of newly synthesized membrane components from RER to Golgi to plasma membrane and is analogous to the pattern previously found for the synthesis and processing of PM proteins in a wide variety of cell types.

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Possible role of cyclic GMP in stimulus-secretion coupling by salt gland of the duck

Cited by 16 publications

References 21 publications

Ions and energy metabolism in duck salt‐gland: possible role of furosemide‐sensitive co‐transport of sodium and chloride

Ions and energy metabolism in duck salt‐gland: possible role of furosemide‐sensitive co‐transport of sodium and chloride

Functional and morphological plasticity of crocodile (Crocodylus porosus) salt glands

Plasma membrane biogenesis in the avian salt gland: A biochemical and quantitative electron microscopic autoradiographic study

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