The Importance of the Uptake Mechanism of Adrenergic Nerves for Non-vascular Smooth Muscle

2015 ◽  
pp. 119-125 ◽  
Author(s):  
U. Trendelenburg
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Adrenergic Nerves ◽  
Uptake Mechanism

Evidence of a K(+)-H(+)-ATPase in vascular smooth muscle cells

1992 ◽  
Vol 262 (6) ◽  
pp. H1955-H1958 ◽  
Author(s):  
R. D. McCabe ◽  
D. B. Young
Keyword(s):  
Smooth Muscle ◽  
Coronary Artery ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Smooth Muscle Cell ◽  
Vascular Smooth Muscle Cells ◽  
Primary Cultures ◽  
Uptake Mechanism ◽  
Atpase Inhibitors ◽  
Canine Coronary Artery

In earlier studies Na(+)-K(+)-adenosinetriphosphatase (ATPase) and Na(+)-K(+)-2Cl- cotransport partially accounted for vascular smooth muscle cell (VSMC) K+ (Rb+) uptake. In other cells Rb+ is taken up by a K(+)-H(+)-ATPase that is sensitive to NC-1300-B, SCH28080, omeprazole, and N-ethylmaleimide (NEM). This study examines the effects of K(+)-H(+)-ATPase inhibitors on VSMC. Rubidium uptake by primary cultures of canine coronary artery (CCA) VSMC or cultured rat aortic (CRA) VSMC line A7r5 was reduced 19-37% by NC-1300-B, SCH28080, or omeprazole. N-ethylmaleimide reduced CCA VSMC K+ content from 1.55 +/- 0.02 to 1.24 +/- 0.06 mu eq/mg protein. The NC-1300-B-sensitive portion of CRA VSMC Rb+ uptake was not blocked by ouabain (0.1 mM) or bumetanide (0.1 mM), but was reduced by alkalinization with 7.5 mM NH4Cl, and increased by acidification with 7.5 mM Na-acetate. Intracellular pH (pHi) of CRA VSMC was reduced 0.14 +/- 0.03 U by NC-1300-B and 0.22 +/- 0.03 U by NEM. pHi of CCA VSMC was reduced 0.20 +/- 0.03 U by omeprazole (1 mM) and 0.20 +/- 0.03 U or 0.20 +/- 0.05 U by amiloride in the absence or presence of omeprazole, respectively. Fluorescence of 2',7'-bis(carboxyethyl)-5-(6')- carboxyethyl)-5-(6')-carboxyfluorescein due to excitation at 500:441 nm in rat aortic strips was reduced by 0.21 +/- 0.02 U by omeprazole and 0.22 +/- 0.03 U by K+ removal and increased by 0.21 +/- 0.06 U by K+ repletion. We conclude that VSMC possess a previously unknown Rb+ uptake mechanism. This newly discovered mechanism helps to maintain K+ gradient and pHi by extruding H+ in exchange for K+, and is presumably a K(+)-H(+)-ATPase similar to those described in other tissues.

Neuronal and Extraneuronal Uptake of 3H-Norepinephrine in the Heart of the Active Bat: An Electron Microscopic Radioautographic Study

1973 ◽  
Vol 31 ◽  
pp. 522-523
Author(s):  
Martin Hagopian ◽  
Michael D. Gershon ◽  
Eladio A. Nunez
Keyword(s):  
Smooth Muscle ◽  
Monoamine Oxidase ◽  
Vascular Smooth Muscle ◽  
Cardiac Muscle ◽  
Maximum Rate ◽  
External Medium ◽  
Extraneuronal Uptake ◽  
Electron Microscopic ◽  
Cardiac Tissues ◽  
High Affinity

The ability of cardiac tissues to take up norepinephrine from an external medium is well known. Two mechanisms, called Uptake and Uptake respectively by Iversen have been differentiated. Uptake is a high affinity system associated with adrenergic neuronal elements. Uptake is a low affinity system, with a higher maximum rate than that of Uptake. Uptake has been associated with extraneuronal tissues such as cardiac muscle, fibroblasts or vascular smooth muscle. At low perfusion concentrations of norepinephrine most of the amine taken up by Uptake is metabolized. In order to study the localization of sites of norepinephrine storage following its uptake in the active bat heart, tritiated norepinephrine (2.5 mCi; 0.064 mg) was given intravenously to 2 bats. Monoamine oxidase had been inhibited with pheniprazine (10 mg/kg) one hour previously to decrease metabolism of norepinephrine.

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