Interaction of Cocaine and G-Strophanthin on the Membrane Potential of Frog Sartorius Muscle Fibres

Pharmacology ◽  
1963 ◽  
Vol 8 (4-6) ◽  
pp. 242-250
Author(s):  
M.H. Draper ◽  
H. Friebel ◽  
K. Karzel
1959 ◽  
Vol 196 (6) ◽  
pp. 1191-1196 ◽  
Author(s):  
S. Ochs ◽  
A. K. Mukherjee

Resting potentials of frog sartorius muscle fibers were taken with microelectrodes at different distances along the length of muscles before and after adding acetylcholine or choline. The mean membrane potential drop and scatter of the potentials recorded in the relatively nerve-free, and in the more densely innervated parts of the muscle, were similar. The loss of direct excitability to electrical and mechanical stimulation was correlated with the concentration of choline or acetylcholine presented. d-tubocurarine added beforehand protected against the depolarizing effect of acetylcholine and choline everywhere along the length of the muscle. A generalized action of acetylcholine and choline and also of d-tubocurarine all along the muscle fibers was inferred. This generalized action at higher concentrations of acetylcholine and choline is believed to be additional to a more specific end plate action.


1987 ◽  
Vol 65 (12) ◽  
pp. 2488-2491 ◽  
Author(s):  
M. J. Mason

The present results demonstrate the sensitivity of the Corning chloride liquid ion exchanger 477913 to L-lactate. Microelectrodes filled with this exchanger showed responses to changes in L-lactate concentration in chloride-free solutions. In these experiments L-lactate replaced gluconate in equimolar amounts. Microelectrodes filled with this exchanger were used to qualitatively detect changes in intracellular anion in chloride-depleted frog sartorius muscle fibres during exposure to extracellular concentrations of L-lactate. The increase in intracellular anion concentration is consistent with the movement of L-lactate into the cell. This microelectrode enables one to qualitatively monitor changes in intracellular L-lactate in chloride-free experiments without incorporating selectivity coefficients.


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