Role of norepinephrine in the lack of reflex tachycardia after angiotensin converting enzyme inhibitor treatment
| Autor: | Kunio Sato, Zenpei Ono, Tetsuo Sakamaki, Kazuhiko Murata, Atsuko Yagi, Shuichi Ichikawa, Tetsuya Nakamura |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Tachycardia
Male medicine.medical_specialty Mean arterial pressure Captopril Blood Pressure Pressoreceptors Baroreflex General Biochemistry Genetics and Molecular Biology Norepinephrine (medication) Diltiazem Norepinephrine Heart Rate Internal medicine Heart rate Reflex medicine Animals cardiovascular diseases Phenylephrine business.industry Hemodynamics General Medicine Endocrinology cardiovascular system Rabbits medicine.symptom business circulatory and respiratory physiology medicine.drug |
| Zdroj: | The Tohoku journal of experimental medicine. 166(4) |
| ISSN: | 0040-8727 |
| Popis: | Angiotensin converting enzyme inhibitors decrease blood pressure without causing reflex tachycardia in hypertensives, but do not always do so in normotensives. To investigate this phenomenon, hemodynamic changes in normotensive rabbits receiving a subpressor dose of norepinephrine were studied following captopril or diltiazem treatment. We also investigated the effect of captopril on baroreceptor reflex in relation to norepinephrine infusion; the baroreflex sensitivity was determined by the relationship between mean arterial pressure and pulse interval receiving graded doses of phenylephrine. Captopril infusion decreased mean arterial pressure and pulse interval from 84 +/- 4 to 74 +/- 5 mmHg and 244 +/- 7.4 to 216 +/- 7.6 msec, respectively. In contrast, in rabbits receiving a norepinephrine infusion captopril lowered mean arterial pressure to the same extent (92 +/- 5 to 76 +/- 3 mmHg, p less than 0.05) without producing reflex tachycardia. When diltiazem was administered, reflex tachycardia occurred in rabbits both with and without a norepinephrine infusion. There was no difference in the baroreflex sensitivity between rabbits receiving norepinephrine with and without captopril treatment. However, the baroreflex curve showed a slight shift to lower pressures after norepinephrine infusion in the rabbits receiving captopril. These results suggest that elevating circulating norepinephrine might be involved in preventing reflex tachycardia after captopril. |
| Databáze: | OpenAIRE |
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