Alteration of 4-aminopyridine-sensitive, voltage-dependent K+-channel in arterial smooth muscle cells of one-kidney, one-clip Goldblatt hypertensive rats.
- Author:
Hoe Suk KIM
1
;
Se Hoon KIM
;
Byeong Hwa JEON
;
Seok Jong CHANG
Author Information
1. Department of Physiology, College of Medicine, Konyang University, 26 Nae-dong, Nonsan, Chungnam, South Korea. sehkim@kytis.konyang.ac.kr
- Publication Type:Original Article
- MeSH:
Adenosine Triphosphate;
Animals;
Charybdotoxin;
Egtazic Acid;
Membrane Potentials;
Muscle, Smooth*;
Myocytes, Smooth Muscle*;
Patch-Clamp Techniques;
Rats*
- From:The Korean Journal of Physiology and Pharmacology
2000;4(5):385-391
- CountryRepublic of Korea
- Language:English
-
Abstract:
Using the patch-clamp technique, we investigated the alteration of 4-aminopyridine(4-AP)-sensitive, voltage-dependent K+ channel (KV) in the mesenteric arterial smooth muscle cell (MASMC) of renovascular hypertensive model, one-kidney one-clip Goldblatt hypertensive rat (GBH). To isolate KV current, internal pipette solution contained 5 mM ATP and 10 mM EGTA. Under these condition, MASMC was depolarized by 4-AP, but charybdotoxin did not affect membrane potential. Membrane potential of hypertensive cell (- 40.3 +/- 3.2 mV) was reduced when compared to that of normotensive cell (-59.5 +/- 2.8 mV). Outward K+ current of hypertensive cell was significantly reduced when compared to normotensive cell. At 60 mV, the outward currents were 19.10 +/- 1.91 and 14.06 +/- 1.05 pA/pF in normotensive cell and hypertensive cell respectively. 4-AP-sensitive K+ current was also smaller in hypertensive cell (4.28 +/- 0.38 pA/pF) than in normotensive cell (7.65 +/- 0.52 pA/pF). The values of half activation voltage (V1/2) and slope factor (k1) as well as the values of half inactivation voltage (V1/2) and slope factor (k1) were virtually similar between GBH and NTR. These results suggest that the decrease of 4-AP-sensitive K+ current contributes to a depolarization of membrane potential, which leads to development of vascular tone in GBH.
