Effects of hemicholinium-3 and sodium ions on choline uptake system in excised superior cervical sympathetic ganglia of rats |
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Authors: | Masao Tamaru Mitsuyoshi Iwata Yutaka Nagata |
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Institution: | (1) Department of Physiology, Fujita-Gakuen Health University School of Medicine, 470-11 Toyoake, Aichi, Japan |
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Abstract: | Active choline uptake by rat superior cervical sympathetic ganglia (SCG), which contain abundant cholinergic nerve terminals, was studied with respect to sensitivity to inhibition by hemicholinium-3 (HC-3) and dependence on extracellular Na+ under standard conditions of assay. Choline was taken up by a single saturable process with apparentK
m=3.07×10–5 M and Vmax=286 pmoles/min/mg protein. Neither denervation followed by degeneration of cholinergic nerve terminals nor axotomy with successive neuronal degeneration significantly decreased in choline uptake by the ganglia in vitro. HC-3 dose-dependently inhibited ganglionic choline uptake more effectively at lower than at higher choline concentrations. HC-3 sensitive inhibition of ganglionic choline uptake was not seen in young rats one week after birth but appeared with maturity, attaining approximately 50% maximal inhibition in adult SCG. Extent of inhibition by HC-3 and Na+ dependence of ganglionic choline uptake was not altered by denervation or axotomy.Abbreviations used (HC-3)
hemicholinium-3
- (HAChU)
high affinity choline uptake
- (LAChU)
low affinity choline uptake
- (SCG)
superior cervical ganglia
- (Ch)
choline
- (ACh)
acetylcholine |
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Keywords: | Hemicholinium-3 rat superior cervical ganglia choline uptake sodium dependency |
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