296 



C. EYZAGUIRRE 



Fig. 8. a. Antidromic impulse recorded with an intracellular lead from soma of a 

 slowly adapting receptor cell. Cell was relaxed with a resting potential of 70 mV. 

 Spike peak 90 mV, the after-negativity disappearing within about 13 msec. No 

 after-positivity seen. Short axon-soma delay responsible for slight inflection or 

 rising phase, b. Slow cell under light stretch. Resting potential reduced by about 

 10 mV. Antidromic impulse followed by after-positivity of 6 mV. (From Eyza- 

 guirre and Kuffler, /. Gen. Physiol. 39 : 121-153, 1955b.) 



5 

 mV. 



50 msec. 



-\ 



Fig. 9. Slow receptor cell. Tracings of three antidromic impulses at high ampli- 

 fication superimposed to compare changes in time course of repolarization phase 

 at three levels of stretch. Spike peaks (not seen in these tracings) remain un- 

 changed during stretch but impulses start from different displaced (depolarized) 

 resting levels. Repolarization phase of impulses in stretched cells undershoots the 

 new resting level (dotted lines), creating the after-positivity. End of repolariza- 

 tion marked by arrows showing progressive shortening of that portion of the 

 cycle by stretch. (From Eyzaguirre and Kuffler, J. Gen. Physiol. 39 : 121-153, 



1955b.) 



