The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms
OBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7) in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7) (25 pmol) was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in ur...
| Hlavní autoři: | , , |
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| Médium: | Článek |
| Jazyk: | English |
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Elsevier España
2013-01-01
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| Edice: | Clinics |
| Témata: | |
| On-line přístup: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1807-59322013000200020 |
| _version_ | 1828464835604512768 |
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| author | Rita C. Oliveira Maria J. Campagnole-Santos Robson A. S. Santos |
| author_facet | Rita C. Oliveira Maria J. Campagnole-Santos Robson A. S. Santos |
| author_sort | Rita C. Oliveira |
| collection | DOAJ |
| description | OBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7) in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7) (25 pmol) was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in urethane-anesthetized male Wistar rats that were untreated or treated (intravenously) with effective doses of selective autonomic receptor antagonists (atenolol, prazosin, methyl-atropine, and hexamethonium) or a vasopressin V1 receptor antagonist [d(CH2)5 -Tyr(Me)-AVP] given alone or in combination. RESULTS: Unexpectedly, the pressor response produced by angiotensin-(1-7) (16 ± 2 mmHg, n = 12), which was not associated with significant changes in heart rate, was not significantly altered by peripheral treatment with prazosin, the vasopressin V1 receptor antagonist, hexamethonium or methyl-atropine. Similar results were obtained in experiments that tested the association of prazosin and atenolol; methyl-atropine and the vasopressin V1 antagonist or methyl-atropine and prazosin. Peripheral treatment with the combination of prazosin, atenolol and the vasopressin V1 antagonist abolished the pressor effect of glutamate; however, this treatment produced only a small decrease in the pressor effect of angiotensin-(1-7) at the rostral ventrolateral medulla. The combination of hexamethonium with the vasopressin V1 receptor antagonist or the combination of prazosin, atenolol, the vasopressin V1 receptor antagonist and methyl-atropine was effective in blocking the effect of angiotensin-(1-7) at the rostral ventrolateral medulla. CONCLUSION: These results indicate that angiotensin-(1-7) triggers a complex pressor response at the rostral ventrolateral medulla that involves an increase in sympathetic tonus, release of vasopressin and possibly the inhibition of a vasodilatory mechanism. |
| first_indexed | 2024-12-11T03:21:19Z |
| format | Article |
| id | doaj.art-20f3b7c11b5349d5b51c9d7aba1cd8f2 |
| institution | Directory Open Access Journal |
| issn | 1807-5932 1980-5322 |
| language | English |
| last_indexed | 2024-12-11T03:21:19Z |
| publishDate | 2013-01-01 |
| publisher | Elsevier España |
| record_format | Article |
| series | Clinics |
| spelling | doaj.art-20f3b7c11b5349d5b51c9d7aba1cd8f22022-12-22T01:22:37ZengElsevier EspañaClinics1807-59321980-53222013-01-01682245252The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanismsRita C. OliveiraMaria J. Campagnole-SantosRobson A. S. SantosOBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7) in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7) (25 pmol) was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in urethane-anesthetized male Wistar rats that were untreated or treated (intravenously) with effective doses of selective autonomic receptor antagonists (atenolol, prazosin, methyl-atropine, and hexamethonium) or a vasopressin V1 receptor antagonist [d(CH2)5 -Tyr(Me)-AVP] given alone or in combination. RESULTS: Unexpectedly, the pressor response produced by angiotensin-(1-7) (16 ± 2 mmHg, n = 12), which was not associated with significant changes in heart rate, was not significantly altered by peripheral treatment with prazosin, the vasopressin V1 receptor antagonist, hexamethonium or methyl-atropine. Similar results were obtained in experiments that tested the association of prazosin and atenolol; methyl-atropine and the vasopressin V1 antagonist or methyl-atropine and prazosin. Peripheral treatment with the combination of prazosin, atenolol and the vasopressin V1 antagonist abolished the pressor effect of glutamate; however, this treatment produced only a small decrease in the pressor effect of angiotensin-(1-7) at the rostral ventrolateral medulla. The combination of hexamethonium with the vasopressin V1 receptor antagonist or the combination of prazosin, atenolol, the vasopressin V1 receptor antagonist and methyl-atropine was effective in blocking the effect of angiotensin-(1-7) at the rostral ventrolateral medulla. CONCLUSION: These results indicate that angiotensin-(1-7) triggers a complex pressor response at the rostral ventrolateral medulla that involves an increase in sympathetic tonus, release of vasopressin and possibly the inhibition of a vasodilatory mechanism.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1807-59322013000200020Angiotensin-(1-7)Rostral Ventrolateral MedullaArterial PressureSympathetic OutputAutonomic BlockadeCholinergic Mechanism |
| spellingShingle | Rita C. Oliveira Maria J. Campagnole-Santos Robson A. S. Santos The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms Clinics Angiotensin-(1-7) Rostral Ventrolateral Medulla Arterial Pressure Sympathetic Output Autonomic Blockade Cholinergic Mechanism |
| title | The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms |
| title_full | The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms |
| title_fullStr | The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms |
| title_full_unstemmed | The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms |
| title_short | The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms |
| title_sort | pressor effect of angiotensin 1 7 in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms |
| topic | Angiotensin-(1-7) Rostral Ventrolateral Medulla Arterial Pressure Sympathetic Output Autonomic Blockade Cholinergic Mechanism |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1807-59322013000200020 |
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