Acetazolamide reduces peripheral afferent transmission in humans.
Carbonic anhydrase has been localized in skeletal muscle and nerve, thus, inhibition with acetazolamide (ACZ) may alter nerve and/or muscle function in healthy humans. ACZ (3 oral doses 14, 8, and 2 h prior to testing) reduced isometric force (37%) and peak to peak electromyographic (EMG) amplitude (1.38 mV to 0.83 mV), while increasing EMG latency associated with a unilateral Achilles tendon-tap. Reflex recovery profiles, following a contralateral conditioning tap, were similar in both placebo and ACZ experiments. ACZ led to significant changes in Hmax/Mmax ratio (52.19/14.42 to 45.73/15.65) and H-reflex latency (34.18 +/- 2.54 ms to 35.24 +/- 2.74 ms). Motor nerve conduction velocity and maximal voluntary isometric torque (knee extensors) were unaltered by ACZ. These data suggest that inhibition of the tendon-tap reflex and associated isometric force, following ACZ, is related to impairment of synaptic integrity between la fibers of the muscle spindle and the alpha motor neuron and not impairment of the muscle spindle or force-generating capacity.
Brechue
W F
WF
Department of Kinesiology, Indiana University, Bloomington 47405, USA.
Koceja
D M
DM
Stager
J M
JM
D000086:Acetazolamide / Q000494:pharmacology*; D000125:Achilles Tendon / Q000187:drug effects; D000328:Adult; D000344:Afferent Pathways / Q000187:drug effects; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology*; D003214:Conditioning, Classical / Q000187:drug effects; D004576:Electromyography; D006181:H-Reflex / Q000187:drug effects; D006801:Humans; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D009431:Neural Conduction / Q000187:drug effects; D010525:Peripheral Nerves / Q000187:drug effects* / Q000502:physiology*; D011930:Reaction Time / Q000187:drug effects; D012026:Reflex, Stretch / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects*; D014459:Ulnar Nerve / Q000187:drug effects / Q000502:physiology
D002257:Carbonic Anhydrase Inhibitors; D000086:Acetazolamide