Hyperpolarization of frog primary afferent fibres caused by activation of a sodium pump.

摘要: 1. In the isolated frog spinal cord repetitive stimulation of a lumbar dorsal root produced sustained negative potential recorded from an adjacent inactive by sucrose gap techniques. This was followed positive potential, indication that terminals were hyperpolarized. Increasing duration tetanus applied to active increased amplitude and after-hyperpolarization which could be up 6 mV 3 min respectively. 2. The hyperpolarization presumably reflected rate sodium pumping. Since it reversibly reduced metabolic inhibitors (dinitrophenol, NaCN) cooling (Q10, 2 . 6) clearly dependent upon intact activity. addition, variety procedures used inhibit pumps (including application ouabain, elimination potassium superfusate, partial substitution lithium for ions) significantly decreased potential. 3. not chemical synaptic transmission since survive prolonged immersion in Ringer solution containing manganese or magnesium ions. 4. It is suggested fibres resulted extracellular concentration horn as result pumping mechanism extruded transported inwards directly activated tetanus.