Hyperthyroidism sinus tachycardia. Sympathetic stimulation or vagal inhibition?
نویسندگان
چکیده
منابع مشابه
Sympathetic responses to cardiopulmonary vagal afferent stimulation during development.
Previous work in our laboratory has demonstrated impairment of cardiopulmonary reflex control of renal sympathetic nerve activity (RSNA) during the newborn period. The present study was designed to test the hypothesis that this delayed maturation is secondary to incomplete central integration of vagal afferent input. Term fetal (135-140 days; n = 6), newborn (3-7 days of age; n = 8), and young ...
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Nasal stimulation provokes hypertension and bradycardia. We report here that such stimulation inhibits baroreflex vagal bradycardia (BVB). In chloralose- and urethan-anesthetized, β-adrenergic receptor-blocked rats, the aortic depressor nerves were cut and electrically stimulated to induce BVB. Nasal application of smoke, warm distilled water, or cold or hot Ringer solution suppressed BVB, but ...
متن کاملEffect of vagal stimulation on the overflow of norepinephrine into the coronary sinus during cardiac sympathetic nerve stimulation in the dog.
In anesthetized dogs with the chest open, supramaximal stimulation of the left cardiac sympathetic nerves at 2 and 4 Hz produced an increase of 40-50% in ventricular contractile force (CF) and of 40-65% in coronary sinus blood flow. At these frequencies of stimulation, norepinephrine (NE) overflow into the coronary sinus was 29.8 +/- 5.1 (SE) and 54.9 +/- 13.2 ng/min, respectively. Concurrent, ...
متن کاملVagal and Sympathetic Effects on the Pacemaker Fibers in the Sinus Venosus of the Heart
1. Action potentials from sinus venosus and auricle fibers of spontaneously beating frog hearts have been recorded with intracellular electrodes. 2. Sinus fibers show a slow depolarization, the pacemaker potential, during diastole. The amplitude of this potential varies in different parts of the sinus. In some fibers the membrane potential falls by 11 to 15 mv. during diastole and the transitio...
متن کاملSympathetic restraint of respiratory sinus arrhythmia: implications for vagal-cardiac tone assessment in humans.
Clinicians and experimentalists routinely estimate vagal-cardiac nerve traffic from respiratory sinus arrhythmia. However, evidence suggests that sympathetic mechanisms may also modulate respiratory sinus arrhythmia. Our study examined modulation of respiratory sinus arrhythmia by sympathetic outflow. We measured R-R interval spectral power in 10 volunteers that breathed sequentially at 13 freq...
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ژورنال
عنوان ژورنال: American Journal of Hypertension
سال: 1999
ISSN: 0895-7061
DOI: 10.1016/s0895-7061(99)80378-1