Age-dependent variation in response to tubocurarine in the isolated rat diaphragm.
The EC50 of tubocurarine was determined in phrenic nerve-hemidiaphragm preparations obtained from 35 Sprague-Dawley rats aged 0-46 days. We measured also the ratio of the fourth to the first twitch in the train-of-four (T4:T1) when the first twitch of the train was depressed to 50% of control. The preparation was not unduly sensitive to tubocurarine at 0 days and there was little evidence of T4:T1 fade. However, by age 11 days the preparation exhibited fade and a three-fold sensitivity to tubocurarine similar to that in the human neonate. We conclude that the phrenic nerve-hemidiaphragm preparation from 11-day-old rats should be a suitable model in which to investigate the biochemical and electrophysiological basis of the sensitivity seen in humans.
Meakin
G
G
University Department of Anaesthesia, Royal Manchester Children's Hospital, Pendlebury.
Morton
R H
RH
Wareham
A C
AC
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D003964:Diaphragm / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects*; D051381:Rats; D014403:Tubocurarine / Q000494:pharmacology*
D014403:Tubocurarine