Perturbation Of The Direction Of Neurite Growth By Pulsed And Focal Electric Fields
Abstract
We have studied the orientation of neurite growth in the culture of embryonic Xenopus neurons in response
to three types of extracellular electric fields: spatially uniform pulsed fields, focally applied steady (DC) fields,
and focally applied pulsed fields. Under uniform pulsed fields, neurites showed a preferential orientation toward
the cathode pole of the field in a manner similar to that previously found for DC fields. The extent of neurite
orientation depended upon the duration, amplitude, and frequency of the pulse but appeared to be similar to
that produced by a uniform DC field of an equivalent time-averaged field intensity. For square pulses of 5 msec
duration, the minimal amplitude and frequency required to produce a detectable orientation of neurite growth
over a period of 24 hr were 2.5 V/cm and 10 Hz, which correspond to a time-averaged field intensity of 125
mV/cm. Steady or pulsed focal fields were applied by passing a current through a micropipette placed near the
growth cone of the neurite. Fields of negative polarity (current sink) were found to attract the growth cone,
whereas fields of positive polarity (current source) were found to deflect the growth cone away from the pipette.
The threshold DC current density needed at the growth cone to perturb its direction of growth within 15 min
was 0.2 to 2 PA/pm’ (or 3 to 30 mV/cm); and for focal pulsed currents (pulse duration 5 msec), a typical
combination of minimal pulse amplitude and frequency was 4 PA/pm’ and 10 Hz. This threshold focal current
is similar to that which occurs at the synaptic cleft during active synaptic activity.
URI
http://profiles.uonbi.ac.ke/npatel/publications/perturbation-neurite-growth-pulsed-and-focal-electric-fieldshttp://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/26421
Citation
Patel, Nilesh; Poo, M-ming. 1984. Perturbation of neurite growth by pulsed and focal electric fields. J. Neuroscience.Publisher
University of Nairobi Department of Medical Physiology
Collections
- Faculty of Health Sciences (FHS) [10377]