Serotonin (5HT) is crucial to normal reflex vagal modulation of heart rate (HR). Reduced baroreflex sensitivity (sBRS) and HR variability (HRV) reflect impaired neural, particularly vagal, control of HR and are independently associated with depression. In conscious, telemetered Flinders-Sensitive Line rats (FSL), a well-validated animal model of depression, we tested the hypothesis that cardiov...

Serotonin (5-HT) is crucial to normal reflex vagal modulation of heart rate (HR). Reduced baroreflex sensitivity [spontaneous baroreflex sensitivity (sBRS)] and HR variability (HRV) reflect impaired neural, particularly vagal, control of HR and are independently associated with depression. In conscious, telemetered Flinders-Sensitive Line (FSL) rats, a well-validated animal model of depression,...

安孫子 保 The work was supported by a grant from the Ministry of Education in Japan. In spite of numerous reports on bradycardia produced by cardiac glycosides hitherto , the mechanism is not completely clarified. Ackermann (1) reported that early digitalis bradycardia was prevented by vagal severance or by administration of atropine. This observation has generally been ac cepted. Heymans and Heyma...

Many basic concepts of cardiac output and arterial pressure control have changed considerably in the past few years. In general, each tissue controls its own local resistance and blood flow regardless of the level of arterial pressure; the sum of the local flows then determines the venous return and cardiac output. However, the arterial pressure is normally controlled by separate mechanisms tha...

Clinical and experimental evidence has shown that myocardial ischemia activates cardiac spinal afferents that mediate sympathoexcitatory reflex responses. During myocardial ischemia, thromboxane A2 (TxA2) is released in large quantities by activated platelets in the coronary circulation of patients with coronary artery disease. We hypothesized that endogenous TxA2 contributes to sympathoexcitat...

Although previous studies in both animals and humans have suggested that cardiac baroreceptors modulate reflex sympathetic vasoconstriction during exercise, more recent studies in conscious animals have not supported this view. To further test this concept in humans, we measured sympathetic nerve discharge with intraneural microelectrodes while we used static handgrip to activate the exercise p...

Cardiac output was determined in dogs over a wide range of pressures before and after preclusion of compensatory reflex mechanisms. When the moderator reflexes are functional, total peripheral resistance increases markedly with moderate reductions in arterial pressure. When reflex alterations of vasomotor tone are obviated, pressure and flow usually vary proportionately as arterial pressure is ...

Deglutition syncope is a relatively rare cause of syncope that belongs to the category of neurally mediated reflex syncopal syndromes. The phenomenon is related to vagal reflex in context to deglutition causing atrioventricular block and acute reduction in cardiac output leading to dizziness or syncope. We present case series of two cases of deglutition syncope, of which first was managed medic...