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Biomedical subjects

A Malliani

Publications and source records attributed to A Malliani.

At least 199 records · Page 11Linked to original sources
PubMed1973

Nervous activity of afferent cardiac sympathetic fibres with atrial and ventricular endings.

1. We recorded the electrical activity of single afferent cardiac fibres isolated from the third and fourth left thoracic sympathetic rami communicantes of anaesthetized cats. Their conduction velocities ranged from 12 to 32 m/sec.2. The endings of each fibre were localized to one cardiac chamber by mechanical probing of the opened heart performed at the end of the experiment.3. The impulse activity was spontaneous and, in fibres with atrial or ventricular endings, it was in phase with a particular atrial or ventricular event.4. This nervous activity increased during increases in pressure occurring in the chamber where the endings were located. Conversely, decreases in pressure were accompanied by decreased nervous discharge.5. In some experiments the left coronary artery was perfused at different flows and pressures. Brief decreases or increases in coronary flow and pressure decreased or increased, respectively, the discharge of fibres with atrial or ventricular endings. Fibres were excited by intracoronary injections of veratridine.6. Cessation of coronary pump flow increased the discharge of fibres with atrial or ventricular endings only when myocardial ischaemia was accompanied by signs of heart failure.7. These afferent cardiac sympathetic fibres which provide the spinal cord with continuous specific information on cardiac events are likely to contribute to the neural control of circulation.

Action Potentials↗
PubMed1971

Spinal sympathetic reflexes initiated by coronary receptors.

1. The main left coronary artery of vagotomized spinal cats was perfused at different flows and pressures. The changes in pressure were limited to the coronary bed.2. Increased coronary flow which increased coronary arterial pressure provoked a reflex increase in sympathetic discharge in the white ramus of the third thoracic spinal nerve and the inferior cardiac nerve. Reflex reductions in activity were not observed.3. Occlusion of the coronary sinus and myocardial ischaemia, due to cessation of pump inflow, evoked similar reflex increases of sympathetic activity. The effect of myocardial ischaemia was apparent before systemic arterial blood pressure fell or left ventricular end-diastolic pressure rose.4. Increased coronary arterial pressure, myocardial ischaemia and coronary sinus occlusion could activate the same preganglionic neurone.5. The afferent limb of the excitatory coronary-sympathetic reflex was in the cardiac sympathetic nerves, mainly on the left. Afferent nerve fibres running in these nerves and in the third left thoracic sympathetic ramus communicans were excited by increased coronary arterial pressure, myocardial ischaemia, and occlusion of the coronary sinus. Inhibition was not observed. Many of the receptors were further localized by direct probing over the coronary vessels and adjacent myocardium.6. Some receptors were excited by increased coronary arterial pressure alone, others by coronary sinus occlusion, and still others by myocardial ischaemia. In addition, some receptors were excited by all three stimuli.

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