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Clonidine attenuation of a cardiogenic hypertensive chemoreflex.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hageman, Gilbert R. Urthaler, Ferdinand James, Thomas N. Swatzell, Roy H. |
| Copyright Year | 1981 |
| Abstract | Clonidine is an antihypertensive agent with a primary action mediated by alpha adrenergic stimulation in the central nervous system, thus inhibiting sympathetic efferent activity. Serotonin activates a cardiogenic hypertensive chemoreflex which induces discharges of sympathetic efferent neurons. The purpose of this study was to determine the effects of intravenous clonidine upon the thoracic sympathetic efferent discharges in chloralose-anesthetized dogs, their peripheral autonomic receptors being blocked with atropine, propranolol, and phentolamine. Efferent nerve traffic was quantified using a Schmitt trigger and Digital PDP8/e computer. Control spontaneous activity (tone) following autonomic blockade was normalized at 100%. Serotonin (100 microgram/ml, 2 ml, left atrium) caused an increase in the reflex efferent sympathetic activity to 192% +/- 16% of control (p less than 0.001). Following clonidine, the tone was decreased to 63% +/- 6% of control, and the reflex sympathetic discharge elicited by serotonin was significantly (p less than 0.001) reduced from 192% to 116% +/- 9% of control tone (before clonidine). The attenuation of the reflexly elicited discharge was significantly (p less than 0.05) greater than the attenuation of the tone. In four dogs that did not receive atropine, the vago-vagal reflex sinus bradycardia induced by serotonin was not affected by clonidine. |
| Starting Page | 89 |
| Ending Page | 98 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://hyper.ahajournals.org/content/hypertensionaha/3/2/240.full.pdf |
| Alternate Webpage(s) | http://hyper.ahajournals.org/content/hypertensionaha/3/2/240.full.pdf?download=true |
| PubMed reference number | 7216378v1 |
| Volume Number | 3 |
| Issue Number | 2 |
| Journal | Hypertension |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Antihypertensive Agents Atropine Body Fluid Discharge Bradycardia CNS disorder Canis familiaris Chloralose Clonidine Dissecting aneurysm of the thoracic aorta Heart Atrium Hypertensive disease Inhibition Left atrial structure Less Than Neurons, Efferent Phentolamine Propranolol Reflex action Serotonin Sick Sinus Syndrome Sinus - general anatomical term |
| Content Type | Text |
| Resource Type | Article |
