Summary
Evidence of a spontaneous release of acetylcholine (ACh) in the right atrium of dog's heart is presented based on the following observations:
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1.
The application of atropine (10−6M) causes an increase in duration of the action potential and a decrease of the resting potential by a few mV within 1–3 min.
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2.
In the presence of eserine and diisoprophylfluorophosphat (DFP), 10−3 M to 10−6 M the duration of the action potential is shortened, the resting potential is increased and the membrane resistence decreased. In the sinus the slow diastolic depolarization is supressed and the preparation will stop beating. Atropine in the concentration of 10−6 M anulls these effects of eserine and DFP.
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3.
The concentration of ACh at the site of the receptor was estimated comparing the shortening of the action potential by known concentrations of ACh with DFP in different concentrations.
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4.
Arrested and beating preparations of dog's auricles were incubated in 5 ccm each of a DFP Tyrode solution. After one hour these bathing solutions were tested for their effects on the resting potential of a fresh preparation. Both kinds of such perfusates causes hyperpolarizations like ACh in concentrations of 5 10−9 to 10−8 M. The amount of released ACh was estimated to range between 0,1 and 0,2 μg/wet weight auricle/h.
According to our measurements no other function of spontaneously released ACh can be suggested than the well known inhibitory effect.
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Literatur
Briscoe, S., and J. H. Burn: The formation of an acetylcholine-like substance by the isolated rabbit heart. J. Physiol. (Lond.) 126, 181–190 (1954).
Burn, J. H.: Function of autonomic transmitters. Baltimore: Williams and Wilkins 1956.
del Castillo, I., and B. Katz: Biophysical aspects of neuromuscular transmission. Progr. Biophysics 6, 121 (1956).
Day, M.: The release of substances like acetylcholine and adrenaline by the isolated rabbit heart. J. Physiol. (Lond.) 134, 558 to 568 (1956).
Harris, E. J., and O. F. Hutter: The action of acetylcholine on the movements of potassium ions in the sinus venosus of the heart. J. Physiol. (Lond.) 133, 58 (1956).
Hoffman, B. F., and E. E. Suckling: Cardiac cellular potentials, effect of vagal stimulation and acetylcholine. Amer. J. Physiol. 173, 312–320 (1953).
Johnson, E. A., and P. A. Robertson: Effect of acetylcholine on the membrane resistance and threshold of atrial muscle fibres. Nature (Lond.), 181, 910–911 (1958).
Katsh, S.: Inhibition of isolated auricles by anticholinesterases and reactivation with atropin and epinephrine. Amer. J. Physiol. 188, 538–542 (1957).
Krayer, O., and J. Fuentes: Changes of heart rate caused by direct cardiac action of reserpine. J. Pharmacol. exp. Ther. 123, 145–152 (1958).
Loewi, O.: Über humorale Übertragbarkeit der Herznervenwirkung. I. Mitteilung. Pflügers Arch. ges. Physiol. 189, 239–242 (1921).
Marshall, J. M., and E. M. Vaughan Williams: Pacemaker potentials. The excitation of isolated rabbit auricles by acetylcholine at low temperatures. J. Physiol. (Lond.) 131, 186–199 (1956).
Paasonen, M. K., and O. Krayer: The release of norepinephrine from the mammalian heart by reserpine. J. Pharmacol. exp. Ther., 123, 153–160 (1958).
Rainer, B., and M. Weatherall. Acetylcholine and potassium movements in rabbit auricles. J. Physiol. (Lond.) 146, 392 (1959).
Rothschuh, K. E., Vorkommen und Funktion des Acetylcholin im Herzen. Klin. Wschr. 32, 1–7 (1954).
Schmidt, R. F.: Über die Acetylcholin-Empfindlichkeit verschiedener Herzabschnitte. Naunyn-Schmiedeberg's Arch. exp. Path. Pharmak. 233, 531–540 (1958).
Trautwein, W., u. J. Dudel: Zum Mechanismus der Membranwirkung des Acetylcholin an der Herzmuskelfaser. Pflügers Arch. ges. Physiol. 266, 324–334 (1958a).
Hemmende und „erregende“ Wirkungen des Acetylcholin am Warmblüterherzen. Zur Frage der spontanen Erregungsbildung. Pflügers Arch. ges. Physiol. 266, 653–664 (1958b).
Trautwein, W., S. W. Kuffler and C. Edwards: Changes in membrane char- acteristics of heart muscle during inhibition. J. gen. Physiol. 40, 135–145 (1956).
Trautwein, W., and W. J. Whalen: Spontaneous release of acetylcholine by the atrium of the heart. XXI. Internat. Congress of Physiol. Sciences (Buenos Aires), Abstracts of communications 274–275 (1959).
Webb, J. L., and P. B. Hollander: The action of acetylcholine and epinephrine on the cellular membrane potentials and contractility of rat atrium. Circulat. Res. 4, 332–336 (1956).
Whalen, W. J.: Science 127, 468 (1958).
Wilson, J. B., and S. Ginsburg: A powerful reactivator of alkylphosphate-inhibited acetylcholinesterase. Biochim. biophys. Acta 18, 168–170 (1955).
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Ausgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft und des U.S. Public Health Service grant Nr. H 3201.
Fulbright Scholar on leave from the Dept. of Physiology, University of California, Los Angeles, California
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Trautwein, W., Whalen, W.J. & Grosse-Schulte, E. Elektrophysiologischer Nachweis spontaner Freisetzung von Acetylcholin im Vorhof des Herzens. Pflügers Archiv 270, 560–570 (1960). https://doi.org/10.1007/BF00362936
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DOI: https://doi.org/10.1007/BF00362936