Fade responses at neuroeffector junction to vagal stimulation in the isolated, blood-perfused dog atrium
| العنوان: | Fade responses at neuroeffector junction to vagal stimulation in the isolated, blood-perfused dog atrium |
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| المؤلفون: | Kimiaki Saegusa, Yasuhiro Ogiwara, Yasuyuki Furukawa, Shigetoshi Chiba |
| المصدر: | The Japanese Journal of Physiology. 38:345-359 |
| بيانات النشر: | Physiological Society of Japan, 1988. |
| سنة النشر: | 1988 |
| مصطلحات موضوعية: | Inotrope, Chronotropic, medicine.medical_specialty, Physostigmine, genetic structures, Physiology, Neuromuscular Junction, Stimulation, Propranolol, Biology, Neuroeffector junction, Calcium Chloride, Dogs, Heart Rate, Parasympathetic Nervous System, Internal medicine, medicine, Animals, Atrium (architecture), Vagus Nerve, General Medicine, Atrial Function, Myocardial Contraction, Acetylcholine, Stimulation, Chemical, eye diseases, Perfusion, Blood, Endocrinology, cardiovascular system, sense organs, psychological phenomena and processes, medicine.drug |
| الوصف: | Effects of physostigmine and of beating rate on the negative chronotropic and inotropic responses to tonic intramural parasympathetic nerve stimulation at a frequency of 5 Hz for 2 min were investigated, using the isolated, blood-perfused dog atrium which was pretreated with propranolol. The responses to stimulation reached a maximum, and then "faded" back toward the control levels during stimulation. Before physostigmine, the fade of the inotropic response was consistently observed but the fade of the chronotropic response was minimal. Both the maximum effect and the fade of the chronotropic response were augmented dose-dependently by physostigmine in spontaneously beating atria. Physostigmine increased the maximum chronotropic response to infusion of acetylcholine (ACh) but did not potentiate the fade response. These results suggest that the potentiation of the fade of the chronotropic response to stimulation after physostigmine is due to decreases in the amount of ACh at the neuroeffector junction. The maximum negative inotropic responses were dose-dependently potentiated similarly by physostigmine in isolated spontaneously beating or paced atria. The fade of the inotropic response in spontaneously beating atria was decreased along with reduction of the rate by physostigmine, whereas the fades in paced atria at 2 and 3 Hz were not changed, showing that decreases in rate during stimulation influenced the reduction of the fade. Increases in contractile force induced by infusion of CaCl2 did not alter the maximum and fade responses to stimulation in 2 Hz paced atria. The blood flow into an isolated atrium was not changed detectably during stimulation. These results suggest that the fade of the inotropic response to parasympathetic nerve stimulation is related subsidiarily to acetylcholinesterase or washout of ACh at the neuroeffector junction in isolated perfused atria. |
| تدمد: | 1881-1396 0021-521X |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d35c637f93415212e9cef6cbd86041acTest https://doi.org/10.2170/jjphysiol.38.345Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....d35c637f93415212e9cef6cbd86041ac |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 18811396 0021521X |
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