Long-term regenerated nerve fibres retain sensitivity to potassium channel blocking agents

Nature ◽  
1983 ◽  
Vol 304 (5927) ◽  
pp. 640-642 ◽  
Author(s):  
Jeffery D. Kocsis ◽  
Stephen G. Waxman
Keyword(s):  
Potassium Channel ◽  
Nerve Fibres ◽  
Blocking Agents ◽  
Channel Blocking

Regenerating mammalian nerve fibres: changes in action potential waveform and firing characteristics following blockage of potassium conductance

1982 ◽  
Vol 217 (1206) ◽  
pp. 77-87 ◽  
Keyword(s):  
Action Potential ◽  
Potassium Channel ◽  
Potassium Conductance ◽  
Compound Action Potential ◽  
Blocking Agent ◽  
Nerve Fibres ◽  
Channel Blocking ◽  
Action Potential Waveform ◽  
Myelinated Fibres ◽  
Firing Properties

Extracellular application of potassium channel blocking agents is known to increase the amplitude and duration of the compound action potential in non-myelinated and demyelinated axons, but not in mature mammalian myelinated fibres. In the present study we used intra-axonal and whole nerve recording techniques to study the effects of the potassium channel blocking agent 4-aminopyridine (4-AP) on regenerating rat nerve fibres. Our results indicate that early regenerating (premyelinated) axons show considerable broadening of the action potential after 4-AP application and late regenerating (myelinated) axons give rise to burst activity following a single stimulus after 4-AP application. 4-AP did not affect spike waveform or firing properties of normal mature sciatic nerve fibres. These results demonstrate the importance of potassium conductance in stabilizing firing properties of myelinated regenerating axons.

Effects of potassium channel-blocking agents on spontaneous discharges from neuromas in rats

1985 ◽  
Vol 63 (2) ◽  
pp. 246-249 ◽  
Author(s):  
Kim J. Burchiel ◽  
Lisa C. Russell
Keyword(s):  
Chronic Pain ◽  
Potassium Channel ◽  
Spontaneous Activity ◽  
Sodium Current ◽  
Potassium Conductance ◽  
Spontaneous Firing ◽  
Tetraethylammonium Bromide ◽  
Blocking Agents ◽  
Baseline Activity ◽  
Channel Blocking

✓ Thirty-five Sprague-Dawley rats with saphenous neuromas underwent acute microfilament recording in the proximal nerve. The effect of the potassium channel-blocking agents, tetraethylammonium bromide (TEA) and 4-aminopyridine, on spontaneous activity in A fibers terminating in the neuroma was observed. The effects of gallamine were also tested. Of the two channel-blocking agents, TEA reliably increased spontaneous firing in active fibers and initiated spontaneous activity in some fibers with no spontaneous baseline discharge. 4-Aminopyridine had no effect on baseline activity of either spontaneously active or quiescent fibers; however, it inhibited spontaneous activity induced by prior TEA treatment. Gallamine application produced effects similar to TEA in that spontaneous activity was dramatically increased. These results imply that a tonic potassium conductance is present in regenerating fibers in the neuroma and that this conductance moderates the tendency toward hyperexcitability and spontaneous firing. Spontanous activity in nociceptive afferent fibers may represent the mechanism of chronic pain and paresthesias that often accompany peripheral nerve injury. These results suggest that agents which either increase potassium conductance or selectively inhibit the sodium current in regenerating axons might be effective in the treatment of these chronic pain syndromes.

scholarly journals Comparative Pharmacodynamics of Eight Calcium Channel Blocking Agents in Japanese Essential Hypertensive Patients.

1996 ◽  
Vol 19 (3) ◽  
pp. 430-437 ◽  
Author(s):  
Shuji SHIMADA ◽  
Yukiko NAKAJIMA ◽  
Koujirou YAMAMOTO ◽  
Yasufumi SAWADA ◽  
Tatsuji IGA
Keyword(s):  
Calcium Channel ◽  
Hypertensive Patients ◽  
Blocking Agents ◽  
Calcium Channel Blocking Agents ◽  
Channel Blocking
Sign in / Sign up

Export Citation Format

Share Document