Abstract
Aortic baroreceptor activity during drug-induced elevation of arterial pressure in intact animals is determined not only by the magnitudes of arterial pressure elevation but also by other mechanisms such as the direct effects of drugs on aortic wall property and on baroreceptors per se. This study aimed to determine the relative contribution of arterial pressure elevation and other mechanisms on aortic baroreceptor activity during intravenous infusion of norepinephrine (NE), phenylephrine (PE) or angiotensin II (Ang II) in intact anesthetized rabbits, all of which were used to assess arterial baroreflex function in vivo. We simultaneously recorded aortic pressure (AP), afferent aortic nerve activity (ANA) and the aortic diameter (AD) during elevation of AP induced by intra-aortic balloon inflation or intravenous infusions of NE, PE, and Ang II. During Ang II-infusion or balloon inflation, AD progressively increased with increases in AP. The relationships among changes in AP, ANA, and AD were similar during balloon inflation and during Ang II infusion which indicated that increases in ANA during Ang II infusion were caused by increases in AD or strain of baroreceptors. In contrast, during NE or PE infusion, ANA increased with no changes or decreases in AD, respectively. The latter results suggest that in intact rabbits increases in ANA during NE or PE infusion resulted from mechanisms other than an increase in strain of baroreceptors, such as the direct excitatory effect on baroreceptors. Thus, different mechanisms were involved in aortic baroreceptor excitation in intact rabbits during elevation of AP caused by the vasopressor drugs, which are commonly used to assess arterial baroreflex function in vivo.
| Original language | English |
|---|---|
| Pages (from-to) | 99-106 |
| Number of pages | 8 |
| Journal | Journal of the Autonomic Nervous System |
| Volume | 40 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Sep 1992 |
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All Science Journal Classification (ASJC) codes
- Neuroscience(all)
- Physiology
- Clinical Neurology
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Mechanisms involved in aortic baroreceptor excitation during drug-induced aortic pressure elevation in intact rabbits. / Hirooka, Yoshitaka; Imaizumi, Tsutomu; Sugimachi, Masaru; Takeshita, Akira.
In: Journal of the Autonomic Nervous System, Vol. 40, No. 2, 09.1992, p. 99-106.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mechanisms involved in aortic baroreceptor excitation during drug-induced aortic pressure elevation in intact rabbits
AU - Hirooka, Yoshitaka
AU - Imaizumi, Tsutomu
AU - Sugimachi, Masaru
AU - Takeshita, Akira
PY - 1992/9
Y1 - 1992/9
N2 - Aortic baroreceptor activity during drug-induced elevation of arterial pressure in intact animals is determined not only by the magnitudes of arterial pressure elevation but also by other mechanisms such as the direct effects of drugs on aortic wall property and on baroreceptors per se. This study aimed to determine the relative contribution of arterial pressure elevation and other mechanisms on aortic baroreceptor activity during intravenous infusion of norepinephrine (NE), phenylephrine (PE) or angiotensin II (Ang II) in intact anesthetized rabbits, all of which were used to assess arterial baroreflex function in vivo. We simultaneously recorded aortic pressure (AP), afferent aortic nerve activity (ANA) and the aortic diameter (AD) during elevation of AP induced by intra-aortic balloon inflation or intravenous infusions of NE, PE, and Ang II. During Ang II-infusion or balloon inflation, AD progressively increased with increases in AP. The relationships among changes in AP, ANA, and AD were similar during balloon inflation and during Ang II infusion which indicated that increases in ANA during Ang II infusion were caused by increases in AD or strain of baroreceptors. In contrast, during NE or PE infusion, ANA increased with no changes or decreases in AD, respectively. The latter results suggest that in intact rabbits increases in ANA during NE or PE infusion resulted from mechanisms other than an increase in strain of baroreceptors, such as the direct excitatory effect on baroreceptors. Thus, different mechanisms were involved in aortic baroreceptor excitation in intact rabbits during elevation of AP caused by the vasopressor drugs, which are commonly used to assess arterial baroreflex function in vivo.
AB - Aortic baroreceptor activity during drug-induced elevation of arterial pressure in intact animals is determined not only by the magnitudes of arterial pressure elevation but also by other mechanisms such as the direct effects of drugs on aortic wall property and on baroreceptors per se. This study aimed to determine the relative contribution of arterial pressure elevation and other mechanisms on aortic baroreceptor activity during intravenous infusion of norepinephrine (NE), phenylephrine (PE) or angiotensin II (Ang II) in intact anesthetized rabbits, all of which were used to assess arterial baroreflex function in vivo. We simultaneously recorded aortic pressure (AP), afferent aortic nerve activity (ANA) and the aortic diameter (AD) during elevation of AP induced by intra-aortic balloon inflation or intravenous infusions of NE, PE, and Ang II. During Ang II-infusion or balloon inflation, AD progressively increased with increases in AP. The relationships among changes in AP, ANA, and AD were similar during balloon inflation and during Ang II infusion which indicated that increases in ANA during Ang II infusion were caused by increases in AD or strain of baroreceptors. In contrast, during NE or PE infusion, ANA increased with no changes or decreases in AD, respectively. The latter results suggest that in intact rabbits increases in ANA during NE or PE infusion resulted from mechanisms other than an increase in strain of baroreceptors, such as the direct excitatory effect on baroreceptors. Thus, different mechanisms were involved in aortic baroreceptor excitation in intact rabbits during elevation of AP caused by the vasopressor drugs, which are commonly used to assess arterial baroreflex function in vivo.
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U2 - 10.1016/0165-1838(92)90021-8
DO - 10.1016/0165-1838(92)90021-8
M3 - Article
C2 - 1464698
AN - SCOPUS:0026644538
VL - 40
SP - 99
EP - 106
JO - Autonomic Neuroscience: Basic and Clinical
JF - Autonomic Neuroscience: Basic and Clinical
SN - 1566-0702
IS - 2
ER -