Carotid Artery Mechanical Properties of Dahl Salt-Sensitive Rats

Abstract

We evaluated the mechanical properties of the carotid artery in anesthetized Dahl rats with or without long-term treatment with the diuretic compound indapamide. The mechanical properties of the carotid artery were evaluated by establishing pressure-volume curves in situ in vivo before and after total relaxation of arterial smooth muscle by potassium cyanide. Dahl salt-sensitive and salt-resistant rats were fed either a low (0.4%) or high (7%) NaCl diet for 5 weeks. In each group, half the rats received for the same period of time oral treatment with indapamide (3 mg/kg per day). Blood pressure, heart rate, and pressure-volume curves were studied at the end of the 5-week period. In untreated Dahl salt-sensitive rats, the pressure-volume curve of the carotid artery was shifted to the right compared with that in untreated Dahl salt-resistant rats. The finding was observed even after potassium cyanide and regardless of the NaCl diet (P < .01 between Dahl salt-sensitive and -resistant rats). Indapamide was able to prevent the development of hypertension in Dahl salt-sensitive rats receiving a high NaCl diet (185 +/- 7 versus 146 +/- 8 mm Hg in untreated and treated Dahl salt-sensitive rats with a high NaCl diet, P < .0005). In the other groups, indapamide had no effect on blood pressure. Indapamide treatment increased carotid arterial static compliance in Dahl salt-sensitive rats with a high or low NaCl diet and to a lesser extent in Dahl salt-resistant rats. The increase was observed even after total relaxation of carotid arterial smooth muscle by potassium cyanide.(ABSTRACT TRUNCATED AT 250 WORDS)