Constancy of motor axon conduction time during growth in rats.
Axon conduction distance, conduction velocity, and conduction time were measured for individual triceps surae motoneurons in Sprague-Dawley rats weighing 230-630 g (i.e., age range 6-16 weeks). Both conduction distance (nerve length) and velocity were closely correlated with weight (r = 0.95 and r = 0.82, respectively). In contrast, conduction time did not change as weight increased nearly threefold. This striking constancy is probably due to a corresponding increase in axon diameter. It could contribute to maintenance of stable motor performance during rapid growth.
Chen
X Y
XY
Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509.
Carp
J S
JS
Wolpaw
J R
JR
D000818:Animals; D001369:Axons / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D008297:Male; D008839:Microelectrodes; D009046:Motor Neurons / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology / Q000254:growth & development