Baroreflex control of coronary conductance in normotensive and renal hypertensive conscious dogs with complete heart block. 1976

S W White, and W L Porges, and J V Reid, and C I Bhagat

1. The autonomic and local control of the circumflex coronary bed evoked through acute rises in aortic pressure (aortic balloon inflation) was analysed in conscious, normotensive and hypertensive dogs in complete heart block with ventricles paced at 100 beats/min. 2. In normotensive dogs there was an initial rise (6-12 s) in circumflex conductance preceding a fall in conductance as aortic pressure increased and was sustained. The initial rise, but not the later fall, in circumflex conductance was partly due to a cholinoreceptor and partly due to alpha-adrenoreceptor mechanisms. Local constrictor mechanisms were responsible for the later fall in conductance. 3. The initial cholinoreceptor component of the rise in circumflex conductance is initiated through arterial baroreflex mechanisms. 4. The initial autonomic mechanisms regulating circumflex conductance appear to be absent in renal hypertension. 5. The absence of the transient autonomic rise in circumflex flow and conductance in response to rapid elevations in aortic pressure in certain forms of hypertension, e.g; during tachyarrhythmias and behavioural disturbances, may result in myocardial ischaemia when it is least appropriate.

UI MeSH Term Description Entries
D006977 Hypertension, Renal Persistent high BLOOD PRESSURE due to KIDNEY DISEASES, such as those involving the renal parenchyma, the renal vasculature, or tumors that secrete RENIN. Hypertensions, Renal,Renal Hypertension,Renal Hypertensions
D010138 Pacemaker, Artificial A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external). Cardiac Pacemaker, Artificial,Artificial Cardiac Pacemaker,Artificial Cardiac Pacemakers,Artificial Pacemaker,Artificial Pacemakers,Cardiac Pacemakers, Artificial,Pacemaker, Artificial Cardiac,Pacemakers, Artificial,Pacemakers, Artificial Cardiac
D011311 Pressoreceptors Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls. Baroreceptors,Receptors, Stretch, Arterial,Receptors, Stretch, Vascular,Stretch Receptors, Arterial,Stretch Receptors, Vascular,Arterial Stretch Receptor,Arterial Stretch Receptors,Baroreceptor,Pressoreceptor,Receptor, Arterial Stretch,Receptor, Vascular Stretch,Receptors, Arterial Stretch,Receptors, Vascular Stretch,Stretch Receptor, Arterial,Stretch Receptor, Vascular,Vascular Stretch Receptor,Vascular Stretch Receptors
D012018 Reflex An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D003326 Coronary Circulation The circulation of blood through the CORONARY VESSELS of the HEART. Circulation, Coronary
D004285 Dogs The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065) Canis familiaris,Dog
D006327 Heart Block Impaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the SINOATRIAL NODE and the right atrium (SA block) or between atria and ventricles (AV block). Heart blocks can be classified by the duration, frequency, or completeness of conduction block. Reversibility depends on the degree of structural or functional defects. Auriculo-Ventricular Dissociation,A-V Dissociation,Atrioventricular Dissociation,A V Dissociation,A-V Dissociations,Atrioventricular Dissociations,Auriculo Ventricular Dissociation,Auriculo-Ventricular Dissociations,Block, Heart,Blocks, Heart,Dissociation, A-V,Dissociation, Atrioventricular,Dissociation, Auriculo-Ventricular,Dissociations, A-V,Dissociations, Atrioventricular,Dissociations, Auriculo-Ventricular,Heart Blocks
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001340 Autonomic Nerve Block Interruption of sympathetic pathways, by local injection of an anesthetic agent, at any of four levels: peripheral nerve block, sympathetic ganglion block, extradural block, and subarachnoid block. Sympathetic Nerve Block,Autonomic Nerve Blocks,Block, Autonomic Nerve,Block, Sympathetic Nerve,Blocks, Autonomic Nerve,Blocks, Sympathetic Nerve,Nerve Block, Autonomic,Nerve Block, Sympathetic,Nerve Blocks, Autonomic,Nerve Blocks, Sympathetic,Sympathetic Nerve Blocks

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