Electrolyte Transports Involved in the Formation of Saliva

Petersen, Olaf

doi:10.1016/b978-0-08-016972-9.50007-0

Cited by 10 publications

(8 citation statements)

References 38 publications

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“…Since GoTo (1980) has reported the K+ conductance of the membrane at rest to be 0.018 S/g, the membrane conductance for Nat, K+, and Cl-under both conditions can be calculated from each transport number and gK value (Table 3). Our present results confirmed that the gK and Na of the basolateral membrane increased during the cholinergic stimulation (IMAI, 1965;PETERSEN, 1972), and also suggested that the increase of g01 of the membrane occurred simultaneously.…”

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confidence: 80%

Intracellular K+ activity in canine submandibular gland cells in resting and its change during stimulation.

1984

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Intracellular K+ activity (aKi) and transmembrane potential differences were simultaneously measured with double-barreled K+ selective microelectrodes in superfused canine submandibular glands at rest and during stimulation. Also intracellular K+ and Na+ concentrations in the same gland were determined by chemical analyses for comparison with the intracellular K+ activity data. The activity coefficient for intracellular K+ thus obtained was 0.67, indicating that virtually all K+ ions in the cells are in diffusible and osmotically active form. Under control conditions, measured values of the resting membrane potential (Em), aK and K+ equilibrium potential (EK) were -40.2+0.6 mV (S.E., n=163), -88.5+1.4 mM (S.E., n=163), -83 mV respectively. Electrochemical potential differences for K+ across the basolateral membrane (d PKIF) were approximately ±43 mV. Acetylcholine (ACh) induced an abrupt membrane hyperpolarization followed by a temporary fall of aKi. The maximum rate of aKi change in the cytoplasm during stimulated conditions was -35.5+0.9 mM f min on the average (n= l0). These results suggest that the membrane permeability increases to K~ upon stimulation. Possible changes in membrane permeabilities to Na+ and Cl-were also discussed. Applying a microelectrode technique, LUNDBERG (1955) first recorded the resting membrane potential of cat submandibular gland cells. He found that the transmembrane potential rapidly hyperpolarized when chorda tympani was stimulated. BURGEN (1956) demonstrated that the salivary gland in the dog lost K+ to blood and saliva during the first period of secretion (K+ transient). Since then, the roles of K+ and other ions in secretory mechanisms in the gland cells have became of great concern among investigators. Subsequently, the ionic dependency of the electrical events induced by stimulation has been investigated in

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confidence: 80%

Intracellular K+ activity in canine submandibular gland cells in resting and its change during stimulation.

1984

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“…Previous reports have described increased sodium and potassium permeability in submandibular gland acinar cells stimulated with acetylcholine (Petersen, 1970(Petersen, , 1972Nishiyama & Petersen, 1974a;Poulsen, 1974). Recently Poulsen and Bledsoe (1977) have demonstrated that the concentration of K § in the interstitial fluid of cat and dog submandibular glands could rise to as high as 18 ms during the period of parasympathetic nerve stimulation.…”

Section: Discussionmentioning

confidence: 96%

Membrane potential and resistance changes induced in salivary gland acinar cells by microiontophoretic application of acetylcholine and adrenergic agonists

Roberts

Petersen

1978

J. Membrain Biol.

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The effects of microiontophoretic applications of catecholamines and acetylcholine on parotid acinar cell membrane potential and resistance were investigated using intracellular microelectrode recording in superfused segments of mouse parotid or rat submandibular glands. Short pulses of acetylcholine and alpha-adrenergic agonists had similar effects, consisting of a marked decrease in membrane resistance accompanied by an initial depolization or hyperpolarization depending on the level of the resting membrane potential. This initial response was followed by a slow hyperpolarization occurring at a time when the resistance was increasing towards the prestimulation level. The equilibrium potential for the initial potential change caused by excitation of the cholinergic receptors was investigated directly by setting the membrane potential at different levels by injecting direct current and stimulating the same cell repeatedly with equal doses of acetylcholine. The equilibrium potential was found to be about -55 mV. The delayed hyperpolarization could not be reversed by passing hyperpolarizing current, but actually increased in size with higher membrane potentials. The minimum latency of the effect of acetylcholine or alpha-adrenergic agonists was 200-500 msec. Excitation of beta-adrenoceptors caused, after a long latency of several seconds, a small depolarization. Epinephrine induced a combined alpha- and beta-adrenergic response, with the alpha-component predominating. Blocking the alpha-adrenoceptors with phentolamine revealed the beta-adrenergic depolarization, while blocking the beta-adrenoceptors with propranolol caused the components of the alpha-adrenergic response to become more pronounced. All three receptors (alpha- and beta-adrenoceptors and cholinergic receptors) were present in individual acini.

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“…Chloride is thought to follow sodium passively but potassium seems to be transported actively, probably by a pump located on the interstitial face of the acinar cell. Although the effects of acetylcholine on the interstitial membrane of the acinar cell are well studied (Schneyer ei ah, 1972;Petersen. 1972), very little is known about the ensuing intracellular steps that ultimately lead to increased nett secxetion of sodium and water.…”

Section: Formation Of Ihe Primary Secretionmentioning

confidence: 99%

“…Thus, all have had plasma-like .sodimn concentrations, chloride concentrations equal to or slightly greater than in plasma and potassium concentrations appreciably greater than in plasma although never more than by 8 niM. This leads to the speculation that the mechanism underKing acinar secretion may be similar in all mammalian compound exocrine glands.The current views on the mechanism of acinar secretion are based mainly on electrophysiological studies on cat siibmaxillary and sublingual glands (Lundberg, 1958;Petersen, 1971;1972) and on micropuncture studies on rat salivary glands (Schneyer et al, 1972). Recently we have also performed micropuncture studies on the isotonic-secreting cat sublingual gland (Kaladelfos and Young, 1973) which is the only gland for which information is available on the potential difference across the huninal face of the acinar cell and on the electrolyte content of the cell cytoplasm (Lundberg, 1958) and luminal fluid (Kaladelfos and Young, 1973) at rest and during stimulation.…”

mentioning

confidence: 99%

Water and Electrolyte Excretion in the Cat Submaxillary Gland Studied Using Micropuncture and Duct Cannulation Techniques

Kaladelfos

1974

Aust J Exp Biol Med

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Summary. Studies on the electrolyte compositioii of the adnar (or primary) secretion and the final saliva of the cat submaxillary gland untlerfjoing parasympatho-and sympathomimetic stimulation have been undertaken using uiicropuncture and duct cannulation techniques for sample collection. The work was undertaken to see to what extent the two-stage secretory model developed previously for rat salivary glands would hold for rather different glands of other species. We find that in genera! tenns the .same two-stage model is apphcable. The primary secretion in both species has plasma-like .sodium and chloride concentrations and potassium concentrations about twice those of plasma; gland stimulation does not greatly alter the composition of this fluid. In the secondary stage, during passage of this fluid altnig the gland excurrent ducts, there is. in both species, extensive ductai absorption of sodium and chloride, although for the cat the absorptive mechanism is more easily saturable. Unlike rat submaxillary ducts, however, those of the cat appear to secrete little potassium. and gland stimulation does not increase the secretory rate of this ion. so that the phenomenon termed acino-tubular balance is not observed. Although both ducts may secrete bicarbonate this is much more conspicuous for the rat. In contrast to parasympathomimetic stimulation, the effects of sympathomimetic stimulation on the two glands were totally different, In the cat a much more vigorous secretorj' response was obtained than in the rat but the striking elevation of salivar>' potassium and bicarbonate concentrations to values in excess of 100 niM seen in the rat did not occur. It Ls concluded that while a two-stage hypothesis may account for secretion of water and electrolytes in many salivary glands, the role of ductai stimulation in the secondary stage and the relative roles of sympathetic and parasympathetic stimulation may vary greatly among species. INTRODUGTION.The adaptation of renal micropuncture techniques to the study of electrolyte transport in .salivan' glands (Martinez, Holzgreve and Frick, 1966;Young and Schogel, 1966) has tlu^own a great deal of light on their secretory mechanisms. For reasons of convenience these micropuncture experiments were carried out 68on the salivary glands of only one species, the rat, although it was soon realized that most rat exocrlne secretions are rather atypical in ha\'ing extremely high potas.sium concentrations. This holds not only for the three major salivary glands, the submaxillary (Young and Schogel, 1966), the sublingual (Martin and Young, 1971a) and the parotid (Mangos and McSherry, 1969), but also for rat sweat glands (Brusilow, Ikai and Gordes, 196S) and lacrinial glands (Alexander, van Lennep and Young, 1972) as well as for the pancreas (Sewell and Young, unpublished observations). It seemed highly desirable to extend our .studies to include a hypotonicsecreting salivary gland from another species in which salivary potassium concentrations were more typical of exocrine glands in ge...

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Electrolyte Transports Involved in the Formation of Saliva

Cited by 10 publications

References 38 publications

Intracellular K+ activity in canine submandibular gland cells in resting and its change during stimulation.

Intracellular K+ activity in canine submandibular gland cells in resting and its change during stimulation.

Membrane potential and resistance changes induced in salivary gland acinar cells by microiontophoretic application of acetylcholine and adrenergic agonists

Water and Electrolyte Excretion in the Cat Submaxillary Gland Studied Using Micropuncture and Duct Cannulation Techniques

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