Korean J Physiol Pharmacol.  1999 Jun;3(3):351-356.

Altered Calcium Current of the Vascular Smooth Muscle in Renal Hypertension

• Nam SC
• Jeong HJ
• Kim W
• Lee J

Abstract

The present study was aimed at investigating whether the calcium current in the vascular smooth muscle (VSM) cells is altered in renal hypertension. Two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertension were made in Sprague-Dawley rats. Rats without clipping the renal artery or implanting DOCA were used as control for 2K1C and DOCA-salt hypertension, respectively. Four weeks after clipping, systolic blood pressure was significantly higher in 2K1C rats than in control (192+/-24 and 119+/-4 mmHg, respectively, n=16 each). DOCA-salt rats also showed a higher blood pressure (180+/-15 mmHg, n=18) compared with control (121+/-6 mmHg, n=14). VSM cells were enzymatically and mechanically isolated from basilar arteries. Single relaxed VSM cells measured 5 ~ 10 mum in width and 70 ~ 150 mum in length were obtained. VSM cells could not be differentiated in size and shape between hypertensive and normotensive rats under light microscopy. High-threshold (L-type) calciumcurrents were recorded using whole-cell patch clamp technique. The amplitude of the current recorded from VSM cells was larger in 2K1C hypertension than in control. Neither the voltage-dependence of the calcium current nor the cell capacitance was significantly affected by 2K1C hypertension. By contrast, the amplitude of the calcium current was not altered in DOCA-salt hypertension. These results suggest that high-threshold calcium current of the VSM cells is altered in 2K1C hypertension, and that calcium channel may not be involved in calcium recruitment of VSM in DOCA-salt hypertension.

Keyword

Two-kidney; One clip hypertension; Deoxycorticosterone acetate-salt hypertension; Vascular smooth muscle; Calcium current

MeSH Terms

Animals
Basilar Artery
Blood Pressure
Calcium Channels
Calcium*
Desoxycorticosterone
Desoxycorticosterone Acetate
Hypertension
Hypertension, Renal*
Microscopy
Muscle, Smooth, Vascular*
Rats
Rats, Sprague-Dawley
Renal Artery
Calcium
Calcium Channels
Desoxycorticosterone