Korean J Nephrol.  2009 Nov;28(6):545-551.

Modulation of Baroreflexes in Hypertensive Rats

• Choi S
• Kim JH
• Sun JM
• Whi HW
• Choi SJ
• Jun JY
• Yoon PJ
• Chung JH
• Kim HI
• Yeum CH

Abstract

PURPOSE
Baroreceptor reflex regulation has been shown to reset towards a higher blood pressure level. This study was designed to assess alterations of chronotropic baroreflexes in two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertensive rats.
METHODS
Arterial pressure and heart rate (HR) were monitored continuously during intravenous infusions of phenylephrine or sodium nitroprusside. Ensuing reflex HR responses during each drug infusion were determined in two ways: (a) at 10 s intervals (time analysis), and (b) with every 10 mmHg change in pressure (pressure analysis).
RESULTS
Both pressor and depressor responses produced by phenylephrine or sodium nitroprusside were comparable between normotensive and hypertensive rats. Both reflex tachycardia and bradycardia were attenuated in 2K1C hypertensive rats as compared with normotensive rats, whereas no significant differences were shown in DOCA-salt hypertensive rats.
CONCLUSION
These results indicate that chronotropic baroreflexes are impaired in 2K1C hypertensive rats, but not in DOCA-salt hypertensive rats.

Keyword

Baroreflex; Blood pressure; Heart rate; Hypertension

MeSH Terms

Animals
Arterial Pressure
Baroreflex
Blood Pressure
Bradycardia
Desoxycorticosterone
Dihydrotachysterol
Heart Rate
Hypertension
Infusions, Intravenous
Nitroprusside
Phenylephrine
Rats
Reflex
Tachycardia
Desoxycorticosterone
Dihydrotachysterol
Nitroprusside
Phenylephrine