292 



C. EYZAGUIRRE 



Fig. 4. Membrane potential changes during stretch in the absence of sensory 

 discharges, a. Intracellular record from the cell body of a slowly adapting cell. 

 Stretch and relaxation marked by arrows. Resting potential of 75 mV reduced by 

 from 6 to 7 mV for the duration of stretch, b. Stretch applied to slow cell for 

 almost 4 sec during conduction block with 01% novocaine. Extracellular 

 recording. Note similarity to a (slower camera speed), c. Impaled fast adapting 

 cell stretched for 3 sec. Potential calibrations same for a and c. Time calibration 

 1 sec in all records. Note the decline of the potentials during maintained stretch. 

 (From Eyzaguirre and Kuffler, J. Gen. Physiol. 39 : 87-119, 1955a.) 



Fig. 5. Intracellular recording from a slow receptor cell. a. Receptor stretched and 

 relaxed twice in succession. First stretch setting up one conducted soma impulse 

 while second stretch causes five discharges after an initial depolarization of 1 2 mV. 

 Impulse peaks 80 mV. Time, 1 sec. b. Slow cell discharging at about 5/sec each 

 triggered by a sensory impulse thereby superimposing the succeeding pre- 

 potentials. Higher amplification — only lower portions of impulses are seen. 

 The difference between impulse intervals reflects fluctuations in frequency. 

 Second beam set near firing level of cell. Time, 0- 1 sec. (From Eyzaguirre and 

 and Kuffler,/. Gen. Physiol. 39 : 87-119, 1955a.) 



