| dc.description.abstract | Ethanol is a known nerve-blocking agent, yet its clinical use is minimal. This is partly due to
unclear dosage levels and not enough knowledge of its pharmacodynamics and overwhelming
dominance of its psychomotor properties. This research intended to investigate into the
pharmacodynamics of ethanol as a nerve blocking agent, try and establish an effective dose that
can be used clinically, as well as comparing its effects on various parts of the motor unit.
A total of 105 sciatic nerve – gastrocnemius muscle specimens were isolated from frogs, Xenopus
laevis. Ethanol at concentrations of 40%, 55% and 70%, each at doses of 1.5g/kg, 2.0g/kg and
2.5g/kg body weight (BW) was administered intraperitoneally, intramuscularly (into the
gastrocnemius) and topically (onto the sciatic nerve). Using EPIC system to monitor muscle
contractions, action potential and/or electromyogram the nerve block effects of each dose /
concentration combination were assessed. The effects on the nerve, neuromuscular junction and
muscle were assessed separately and compared, then as a single unit.
Results showed that intraperitoneally administered ethanol had no effect on neuromuscular
function. Intramuscular injections took 2.5 to 9.0 minutes to attain complete paralysis, and lasted
for 29.5 to 61.0 minutes, depending on concentration and dose (>/= 55%; >/= 2.0g/kg BW).
Topically applied ethanol took 15 to 30 seconds to block the nerve completely, depending on the
concentration (>/= 40%). The blockade lasted for 5 to 10 minutes. Intramuscularly injected
ethanol reduced the amplitude of indirectly elicited electromyography more than the directly
evoked one.
It was concluded that to achieve a complete and sustained ethanol nerve block, at least 55%
concentration, 2.0g/kg BW dose and intramuscular route are required. The duration of blockade
depends on concentration and dose administered. Ethanol affects both nerve and muscle. The
effect is more pronounced and instant on the nerve than on muscle. | en_US |
