Cardiovascular and Respiratory Effects of Endothelin in the Ventrolateral Medulla of the Normotensive Rat
| Autor: | Kendell Yates, Jim O’Leary, Rogelio Mosqueda-Garcia, Tadashi Inagami |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
medicine.medical_specialty
Sympathetic Nervous System Respiratory System Blood Pressure Kidney Peptides Cyclic Rats Sprague-Dawley Piperidines Heart Rate Internal medicine Internal Medicine medicine Animals Respiratory function Respiratory system Medulla Medulla Oblongata Endothelin receptor antagonist business.industry Endothelins Hemodynamics Rostral ventrolateral medulla Rats Endocrinology Blood pressure Respiratory Physiological Phenomena cardiovascular system Medulla oblongata Endothelin receptor business Oligopeptides |
| Zdroj: | Hypertension. 26:263-271 |
| ISSN: | 1524-4563 0194-911X |
| Popis: | Abstract We studied the relevance of the ventrolateral medulla for the cardiovascular and respiratory effects of endothelin-1 in urethane-anesthetized rats. Microinjection of endothelin-1 into the rostral ventrolateral medulla (RVLM) evoked pressor and bradycardic effects followed by sustained decreases in blood pressure, bradycardia, and respiratory depression. These effects were inhibited by endothelin-A receptor antagonists (BQ-123 and BQ-610) but not by endothelin-B antagonists. In the caudal ventrolateral medulla (CVLM) endothelin-1 decreased blood pressure, renal sympathetic nerve activity, respiratory frequency, and phrenic nerve activity, whereas heart rate increased. Pretreatment with BQ-123 in the CVLM increased respiratory frequency by 15±6 breaths per minute and prevented the effects of intra-CVLM administration of endothelin-1. In separate experiments, the intracisternal administration of endothelin-1 (20 pmol) to rats pretreated with saline in both the RVLM and CVLM resulted in a hypotensive and bradycardic phase that was followed by hypertension (50±15 mm Hg), bradycardia, and 100% mortality. In a separate group, pretreatment with BQ-123 in the RVLM and CVLM completely inhibited the hypotensive phase and reduced by 83% the subsequent rise in blood pressure evoked by endothelin-1. Cardiorespiratory arrest was prevented in all the rats in this group. Selective endothelin receptor blockade in the RVLM attenuated the hypertensive period of intracisternal administration of endothelin-1 and prevented mortality by 33%, whereas in the CVLM the endothelin receptor antagonist inhibited the initial hypotension and reduced mortality by 25%. Our results support the concept that in the ventral medulla, endothelin-1 can modulate cardiovascular and respiratory function. |
| Databáze: | OpenAIRE |
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