This project quantitates membrane excitation steps and Ca++ release which follows to trigger vascular muscle contraction. Intracellular Ca++ will be quantitated and localized by the birefringence signal intrinsic to the cells and by intracellular Ca++ indicators that will be introduced into the cells via liposomes or by tight seal pipettes. Extracellular Ca++ measurements will be made with optical indicators to indicate Ca++ influx to allow the fraction of Ca++ entering the cell to be separated from intracellular release in living cells. In addition to optical and electrical studies of activation, the role of Ca++ entry and voltage in activation of the contractile apparatus will be studied by manipulation of extracellular Ca++ and K+. Single ion channel recording by patch clamp techniques and whole single cell recording in voltage clamp will allow studies of Ca++ currents and K+ currents and provide information about the control of ion channels that determine membrane excitability. Those ion channels activated by intracellular Ca++ will be explored. The interaction between ouabain and other inhibitors of the Na+ pump with intracellular Ca++ will be studied. These measurements of ion currents will also allow the intracellular ion composition of vascular muscle cells to be controlled for the first time. Preparations include the neonatal rat azygous vein and adult rat cerebral and mesenteric arteries. In each case, studies of isolated single cells will be correlated with studies on pressurized perfused segments of the same blood vessels in vitro to allow cellular level mechanisms to be correlated with blood vessel excitation and contraction properties.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL038537-03
Application #
3354850
Study Section
Experimental Cardiovascular Sciences Study Section (ECS)
Project Start
1987-09-01
Project End
1993-08-31
Budget Start
1988-09-01
Budget End
1989-08-31
Support Year
3
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Providence Medical Center (Portland, OR)
Department
Type
DUNS #
City
Portland
State
OR
Country
United States
Zip Code
97213
Hermsmeyer, K; White, A C; Triggle, D J (1995) Decreased dihydropyridine receptor number in hypertensive rat vascular muscle cells. Hypertension 25:731-4
Mishra, S K; Hermsmeyer, K (1994) Resting state block and use independence of rat vascular muscle Ca++ channels by Ro 40-5967. J Pharmacol Exp Ther 269:178-83
Mishra, S K; Hermsmeyer, K (1994) Selective inhibition of T-type Ca2+ channels by Ro 40-5967. Circ Res 75:144-8
Mishra, S K; Hermsmeyer, K (1994) Inhibition of signal Ca2+ in dog coronary arterial vascular muscle cells by Ro 40-5967. J Cardiovasc Pharmacol 24:1-7
Bian, K; Hermsmeyer, K (1994) Glyburide actions on the dihydropyridine-sensitive Ca2+ channel in rat vascular muscle. J Vasc Res 31:256-64
Self, D A; Bian, K; Mishra, S K et al. (1994) Stroke-prone SHR vascular muscle Ca2+ current amplitudes correlate with lethal increases in blood pressure. J Vasc Res 31:359-66
Bian, K; Hermsmeyer, K (1993) Ca2+ channel actions of the non-dihydropyridine Ca2+ channel antagonist Ro 40-5967 in vascular muscle cells cultured from dog coronary and saphenous arteries. Naunyn Schmiedebergs Arch Pharmacol 348:191-6
Hermsmeyer, K (1993) Calcium channel function in hypertension. J Hum Hypertens 7:173-6
Baker, J R; Hedwall, P R; Hermsmeyer, K (1992) Subcellular distribution of hydralazine in rat single vascular muscle cells. Cell Biol Int Rep 16:1023-39
Erne, P; Hermsmeyer, K (1991) Modulation of intracellular calcium by potassium channel openers in vascular muscle. Naunyn Schmiedebergs Arch Pharmacol 344:706-15

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