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Occipital Artery Function during the Development of 2-Kidney, 1-Clip Hypertension in Rats.

Chelko SP, Schmiedt CW, Lewis TH, Robertson TP, Lewis SJ - Int J Vasc Med (2014)

Bottom Line: This study compared the contractile responses elicited by angiotensin II (AII), arginine vasopressin (AVP), and 5-hydroxytryptamine (5-HT) in isolated occipital arteries (OAs) from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats.OAs were isolated and bisected into proximal segments (closer to the common carotid artery) and distal segments (closer to the nodose ganglion) and mounted separately on myographs.The diminished responsiveness to AII may alter the physiological status of OAs in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.

ABSTRACT
This study compared the contractile responses elicited by angiotensin II (AII), arginine vasopressin (AVP), and 5-hydroxytryptamine (5-HT) in isolated occipital arteries (OAs) from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. OAs were isolated and bisected into proximal segments (closer to the common carotid artery) and distal segments (closer to the nodose ganglion) and mounted separately on myographs. On day 9, 2K-1C rats had higher mean arterial blood pressures, heart rates, and plasma renin concentrations than SHAM rats. The contractile responses to AII were markedly diminished in both proximal and distal segments of OAs from 2K-1C rats as compared to those from SHAM rats. The responses elicited by AVP were substantially greater in distal than in proximal segments of OAs from SHAM rats and that AVP elicited similar responses in OA segments from 2K-1C rats. The responses elicited by 5-HT were similar in proximal and distal segments from SHAM and 2K-1C rats. These results demonstrate that continued exposure to circulating AII and AVP in 2K-1C rats reduces the contractile efficacy of AII but not AVP or 5-HT. The diminished responsiveness to AII may alter the physiological status of OAs in vivo.

No MeSH data available.


Related in: MedlinePlus

Dose-response effects of arginine vasopressin on tension of proximal and distal occipital artery segments from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. The data are presented as mean ± SEM of the responses expressed as a percentage of that elicited by 80 mM K+ (%TK). There were 8 segments in each group.
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fig2: Dose-response effects of arginine vasopressin on tension of proximal and distal occipital artery segments from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. The data are presented as mean ± SEM of the responses expressed as a percentage of that elicited by 80 mM K+ (%TK). There were 8 segments in each group.

Mentions: AVP elicited concentration-dependent contractions in proximal and distal OA segments taken from SHAM and 2K-1C rats (Figure 2). AVP responses were greater in distal segments than in proximal segments from SHAM and 2K-1C rats. The contractions elicited by AVP in proximal and distal segments from 2K-1C rats were similar to those in the corresponding segments from SHAM rats. EC50 values were similar between proximal and distal OA segments from SHAM rats and from 2K-1C rats (Table 2). EC50 values were similar between SHAM and 2K-1C segments. The maximal responses (Emax⁡, %TK) elicited by AVP in distal segments were greater than those in proximal segments from SHAM and 2K-1C rats (Table 2). The responses in proximal and distal segments from 2K-1C rats were similar to those in the respective segments from SHAM rats.


Occipital Artery Function during the Development of 2-Kidney, 1-Clip Hypertension in Rats.

Chelko SP, Schmiedt CW, Lewis TH, Robertson TP, Lewis SJ - Int J Vasc Med (2014)

Dose-response effects of arginine vasopressin on tension of proximal and distal occipital artery segments from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. The data are presented as mean ± SEM of the responses expressed as a percentage of that elicited by 80 mM K+ (%TK). There were 8 segments in each group.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4129976&req=5

fig2: Dose-response effects of arginine vasopressin on tension of proximal and distal occipital artery segments from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. The data are presented as mean ± SEM of the responses expressed as a percentage of that elicited by 80 mM K+ (%TK). There were 8 segments in each group.
Mentions: AVP elicited concentration-dependent contractions in proximal and distal OA segments taken from SHAM and 2K-1C rats (Figure 2). AVP responses were greater in distal segments than in proximal segments from SHAM and 2K-1C rats. The contractions elicited by AVP in proximal and distal segments from 2K-1C rats were similar to those in the corresponding segments from SHAM rats. EC50 values were similar between proximal and distal OA segments from SHAM rats and from 2K-1C rats (Table 2). EC50 values were similar between SHAM and 2K-1C segments. The maximal responses (Emax⁡, %TK) elicited by AVP in distal segments were greater than those in proximal segments from SHAM and 2K-1C rats (Table 2). The responses in proximal and distal segments from 2K-1C rats were similar to those in the respective segments from SHAM rats.

Bottom Line: This study compared the contractile responses elicited by angiotensin II (AII), arginine vasopressin (AVP), and 5-hydroxytryptamine (5-HT) in isolated occipital arteries (OAs) from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats.OAs were isolated and bisected into proximal segments (closer to the common carotid artery) and distal segments (closer to the nodose ganglion) and mounted separately on myographs.The diminished responsiveness to AII may alter the physiological status of OAs in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.

ABSTRACT
This study compared the contractile responses elicited by angiotensin II (AII), arginine vasopressin (AVP), and 5-hydroxytryptamine (5-HT) in isolated occipital arteries (OAs) from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. OAs were isolated and bisected into proximal segments (closer to the common carotid artery) and distal segments (closer to the nodose ganglion) and mounted separately on myographs. On day 9, 2K-1C rats had higher mean arterial blood pressures, heart rates, and plasma renin concentrations than SHAM rats. The contractile responses to AII were markedly diminished in both proximal and distal segments of OAs from 2K-1C rats as compared to those from SHAM rats. The responses elicited by AVP were substantially greater in distal than in proximal segments of OAs from SHAM rats and that AVP elicited similar responses in OA segments from 2K-1C rats. The responses elicited by 5-HT were similar in proximal and distal segments from SHAM and 2K-1C rats. These results demonstrate that continued exposure to circulating AII and AVP in 2K-1C rats reduces the contractile efficacy of AII but not AVP or 5-HT. The diminished responsiveness to AII may alter the physiological status of OAs in vivo.

No MeSH data available.


Related in: MedlinePlus