After a change in cardiac output, the magnitude of potential blood volume redistribution was investigated in 10 dogs anesthetized with chloralose. All of the venous return was pumped into a reservoir, using servocontrolled pumps to maintain fixed superior and inferior vena cava pressures. The cardiac output was set at various levels by pumping from the reservoir into the right atrium. Changes i...

The reflex control of pulse interval during erect bicycle exercise was studied in nine normal subjects aged 18 to 28, breathing an oxygen-rich mixture. Rises in the directly measured arterial pressure were produced by intravenous injections of phenylephrine, and systolic pressure was correlated with the following pulse interval. The slope of the systolic pressure-pulse interval relation was use...

We describe the discovery of the trigemino-cardiac reflex by Schaller in 1999 and the continued improvement of the knowledge about the trigemino-cardiac reflex involved in neurosurgery, especially in skull base surgery, during the past several years. The achieved medical progress could be gained only by the practical experience described by different case reports and later case series that have...

Ventilation with positive end-expiratory pressure (PEEP) is associated with reduced cardiac output, but the mechanisms involved are controversial. Possible explanations include increased intrathoracic pressure, reflex changes in myocardial inotropism, pulmonary vascular obstruction and abnormal ventricular interaction. Three types of conscious canine preparations were developed to examine simul...

The oculocardiac reflex (OCR) is a well–described cardiac depressor reflex that may result in significant cardiac rate or rhythm changes, sinus and junctional bradycardia, heart block or asystole. It is also known by the eponym Aschner-Dagnini Reflex, being independently reported in 1908 by both Guiseppe Dagnini and later Bernard Aschner.1,2 The OCR is classically depicted as being precipitated...

It is now evident that atrial natriuretic factor (ANF) exerts neural effects in addition to vasorelaxant, depressor, and renal effects. The study by Ferrari et al examined the effects of intravenous ANF at doses within the pathophysiological range on arterial baroreceptor reflex control of heart rate and vascular resistance in conscious rats. Their results indicate that ANF markedly potentiated...

Stimulation of the trigeminal nerve evokes a dramatic decrease in heart rate and blood pressure, and this reflex has generally been termed the trigeminocardiac reflex. A subset of the trigeminocardiac reflex is the diving reflex in which the nasal mucosa is stimulated with water or air-borne chemical irritants. Activation of the diving reflex evokes a pronounced bradycardia, mediated by increas...

The trigemino-cardiac reflex (TCR) is a brainstem reflex that manifests as adverse cardiorespiratory events upon the stimulation of sensory branches of the fifth cranial nerve. This reflex is mainly investigated in different neurosurgical procedures and intervention. This reflex is commonly considered as an acute and mild physiological response. On the other hand, more devastating and chronic n...