Strain differences in baroceptor reflex in adult Wistar Kyoto rats
OBJECTIVES: A subset of normotensive Sprague-Dawley rats show lower baroreflex sensitivity; however, no previous study investigated whether there are differences in baroreflex sensitivity within this subset. Our study compared baroreflex sensitivity among conscious rats of this specific subtype. METHODS: Male Wistar Kyoto (WKY) rats (16 weeks old) were studied. Cannulas were inserted into the abdominal aortic artery through the right femoral artery to measure mean arterial pressure (MAP) and heart rate (HR). Baroreflex gain was calculated as the ratio between change in HR and MAP variation (ΔHR/ΔMAP) in response to a depressor dose of sodium nitroprusside (SNP, 50 µg/kg, i.v.) and a pressor dose of phenylephrine (PE, 8 µg/kg, i.v.). Rats were divided into four groups: 1) low bradycardic baroreflex (LB), baroreflex gain (BG) between -1 and -2 bpm/mmHg tested with PE; 2) high bradycardic baroreflex (HB), BG < -2 bpm/mmHg tested with PE; 3) low tachycardic baroreflex (LT), BG between -1 and -2 bpm/mmHg tested with SNP and; 4) high tachycardic baroreflex (HT), BG < -2 bpm/mmHg tested with SNP. Significant differences were considered for p < 0.05. RESULTS: Approximately 37% of the rats showed a reduced bradycardic peak, bradycardic reflex and decreased bradycardic gain of baroreflex while roughly 23% had a decreased basal HR, tachycardic peak, tachycardic reflex and reduced sympathetic baroreflex gain. No significant alterations were noted with regard to basal MAP. CONCLUSION: There is variability regarding baroreflex sensitivity among WKY rats from the same laboratory.
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Faculdade de Medicina / USP
2010
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oai:scielo:S1807-593220100002000132010-03-03Strain differences in baroceptor reflex in adult Wistar Kyoto ratsValenti,Vitor E.Abreu,Luiz Carlos deImaizumi,CaioPetenusso,MárcioFerreira,Celso Baroreflex Rats Inbred WKY Sympathetic Nervous System Parasympathetic Nervous System Autonomic Nervous System OBJECTIVES: A subset of normotensive Sprague-Dawley rats show lower baroreflex sensitivity; however, no previous study investigated whether there are differences in baroreflex sensitivity within this subset. Our study compared baroreflex sensitivity among conscious rats of this specific subtype. METHODS: Male Wistar Kyoto (WKY) rats (16 weeks old) were studied. Cannulas were inserted into the abdominal aortic artery through the right femoral artery to measure mean arterial pressure (MAP) and heart rate (HR). Baroreflex gain was calculated as the ratio between change in HR and MAP variation (ΔHR/ΔMAP) in response to a depressor dose of sodium nitroprusside (SNP, 50 µg/kg, i.v.) and a pressor dose of phenylephrine (PE, 8 µg/kg, i.v.). Rats were divided into four groups: 1) low bradycardic baroreflex (LB), baroreflex gain (BG) between -1 and -2 bpm/mmHg tested with PE; 2) high bradycardic baroreflex (HB), BG < -2 bpm/mmHg tested with PE; 3) low tachycardic baroreflex (LT), BG between -1 and -2 bpm/mmHg tested with SNP and; 4) high tachycardic baroreflex (HT), BG < -2 bpm/mmHg tested with SNP. Significant differences were considered for p < 0.05. RESULTS: Approximately 37% of the rats showed a reduced bradycardic peak, bradycardic reflex and decreased bradycardic gain of baroreflex while roughly 23% had a decreased basal HR, tachycardic peak, tachycardic reflex and reduced sympathetic baroreflex gain. No significant alterations were noted with regard to basal MAP. CONCLUSION: There is variability regarding baroreflex sensitivity among WKY rats from the same laboratory.info:eu-repo/semantics/openAccessFaculdade de Medicina / USPClinics v.65 n.2 20102010-01-01info:eu-repo/semantics/articletext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S1807-59322010000200013en10.1590/S1807-59322010000200013 |
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Valenti,Vitor E. Abreu,Luiz Carlos de Imaizumi,Caio Petenusso,Márcio Ferreira,Celso |
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Valenti,Vitor E. Abreu,Luiz Carlos de Imaizumi,Caio Petenusso,Márcio Ferreira,Celso Strain differences in baroceptor reflex in adult Wistar Kyoto rats |
author_facet |
Valenti,Vitor E. Abreu,Luiz Carlos de Imaizumi,Caio Petenusso,Márcio Ferreira,Celso |
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Valenti,Vitor E. |
title |
Strain differences in baroceptor reflex in adult Wistar Kyoto rats |
title_short |
Strain differences in baroceptor reflex in adult Wistar Kyoto rats |
title_full |
Strain differences in baroceptor reflex in adult Wistar Kyoto rats |
title_fullStr |
Strain differences in baroceptor reflex in adult Wistar Kyoto rats |
title_full_unstemmed |
Strain differences in baroceptor reflex in adult Wistar Kyoto rats |
title_sort |
strain differences in baroceptor reflex in adult wistar kyoto rats |
description |
OBJECTIVES: A subset of normotensive Sprague-Dawley rats show lower baroreflex sensitivity; however, no previous study investigated whether there are differences in baroreflex sensitivity within this subset. Our study compared baroreflex sensitivity among conscious rats of this specific subtype. METHODS: Male Wistar Kyoto (WKY) rats (16 weeks old) were studied. Cannulas were inserted into the abdominal aortic artery through the right femoral artery to measure mean arterial pressure (MAP) and heart rate (HR). Baroreflex gain was calculated as the ratio between change in HR and MAP variation (ΔHR/ΔMAP) in response to a depressor dose of sodium nitroprusside (SNP, 50 µg/kg, i.v.) and a pressor dose of phenylephrine (PE, 8 µg/kg, i.v.). Rats were divided into four groups: 1) low bradycardic baroreflex (LB), baroreflex gain (BG) between -1 and -2 bpm/mmHg tested with PE; 2) high bradycardic baroreflex (HB), BG < -2 bpm/mmHg tested with PE; 3) low tachycardic baroreflex (LT), BG between -1 and -2 bpm/mmHg tested with SNP and; 4) high tachycardic baroreflex (HT), BG < -2 bpm/mmHg tested with SNP. Significant differences were considered for p < 0.05. RESULTS: Approximately 37% of the rats showed a reduced bradycardic peak, bradycardic reflex and decreased bradycardic gain of baroreflex while roughly 23% had a decreased basal HR, tachycardic peak, tachycardic reflex and reduced sympathetic baroreflex gain. No significant alterations were noted with regard to basal MAP. CONCLUSION: There is variability regarding baroreflex sensitivity among WKY rats from the same laboratory. |
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Faculdade de Medicina / USP |
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2010 |
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http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1807-59322010000200013 |
work_keys_str_mv |
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