Beta-adrenoceptors in vascular capacitance responses to unloading of carotid baroreceptors in anesthetized dogs
| Autor: | S. M. Poucher, F. Karim |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Baroreceptor
Physiology Adrenergic beta-Antagonists Blood Pressure Pressoreceptors Propanolamines Dogs Heart Rate Physiology (medical) Receptors Adrenergic beta Vascular Capacitance Carnivora Medicine Animals biology business.industry Fissipedia Antagonist Imidazoles biology.organism_classification Blood pressure medicine.anatomical_structure Carotid Arteries Carotid Sinus Anesthesia Circulatory system Cardiology and Cardiovascular Medicine business Blood vessel |
| Zdroj: | The American journal of physiology. 273(4) |
| ISSN: | 0002-9513 |
| Popis: | The role of β- and α-adrenoceptors in the total vascular capacitance responses to changing pressure in vascularly isolated carotid sinuses of anesthetized and atropinized dogs was investigated. A change in vascular capacitance was determined by measuring the shift of blood in and out of a reservoir that was connected to the aorta and maintained at a constant pressure. Changes in carotid sinus pressure from 135 to 57 mmHg and back to 137 mmHg resulted in a rapid vascular capacitance response of ∼30 ml in the absence of adrenoceptor antagonists. Administration of a β2-adrenoceptor antagonist (ICI-118551) caused a significant enhancement of the capacitance responses to similar decreases and increases in carotid sinus pressure (∼130%). Administration of a β1-adrenoceptor antagonist (CGP-20712A) did not cause any further enhancement of the responses. However, an α-blocker (phentolamine) reduced the responses by 75%. The results suggest that in the presence of a β2-adrenoceptor antagonist vascular capacitance responses to loading and unloading of baroreceptors are greatly enhanced and that patients suffering from orthostatic syncope may benefit from this kind of drug. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|