Involvement of the sodium-potassium pump in the mechanism of postjunctional supersensitivity of the vas deferens of the guinea pig.
Gerthoffer-WT; Fedan-JS; Westfall-DP; Goto-K; Fleming-WW
J Pharmacol Exp Ther 1979 Jul; 210(1):27-36
The relationship between the electrogenic sodium-potassium (NaK) pump and postjunctional supersensitivity of guinea-pig vas deferens was studied. The vasa deferentia were removed from male guinea- pigs, desheathed, and exposed to ouabain (630604) followed by methoxamine (390283). Pairs of vasa deferentia were either unoperated or surgically denervated. The effects of ouabain or reduced extracellular potassium were determined. Nuclear, mitochondrial, microsomal, and supernatant fractions of homogenized vasa deferentia were assayed for NaK adenosinetriphosphatase (ATPase). Neither ouabain nor reduced potassium depolarized the cell membranes of denervated vasa deferentia, nor did ouabain enhance methoxamine sensitivity. Denervation of the vasa deferentia resulted in reduced ATPase in the subcellular fractions. The authors suggest that interruption of the excitatory innervation of the vas deferens partially inhibits the NaK pump by reducing ATPase activity. Inhibition of the pump may cause depolarization of the cell membrane due to the electrogenicity of the pump.
NIOSH-Author; Laboratory-animals; Enzyme-activity; Cell-biology; Cellular-reactions; Reproductive-system
Journal of Pharmacology and Experimental Therapeutics