A pharmacological evaluation of the pull-up test for muscle relaxation in rats.
The pull-up test for muscle relaxation is described and validated. At testing, rats were evaluated for their ability to recover ('pull-up') from a fully inverted head-down position. Control animals rapidly regained position (median: 1 s). Known muscle relaxants increased latency to pull-up compared to controls. The test proved sensitive to the effects of barbiturates and benzodiazepines which produced graded dose-response functions. In general, results in the pull-up test corresponded with known potencies, with weaker muscle relaxants such as clobazam and oxazepam being less active. The test was relatively insensitive to non-benzodiazepine compounds (e.g., haloperidol, etomidate, morphine, fentanyl and risperidone) producing cataleptic, catatonic, neuroleptic, analgesic, sedative or hypnotic effects. In terms of ED50 values for barbiturates and benzodiazepines, the pull-up test correlated significantly with ED50s from the rotarod test, the antipentylenetetrazol test, ataxia in rats and muscle relaxation in cats. It was concluded that the pull-up test was relatively specific for muscle relaxation and provided a simple alternative to more time-consuming or equipment-intensive tests.
Wilson
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NE
Behavioural Analysis and Behavioural Biology Research Centre, University of Ulster at Jordanstown, Co. Antrim, Northern Ireland, UK.
Meert
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TF
Shephard
R A
RA
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology; D000927:Anticonvulsants / Q000494:pharmacology; D014150:Antipsychotic Agents / Q000494:pharmacology; D001463:Barbiturates / Q000494:pharmacology; D001569:Benzodiazepines; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009125:Muscle Relaxants, Central / Q000494:pharmacology*; D009126:Muscle Relaxation / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
D014151:Anti-Anxiety Agents; D000927:Anticonvulsants; D014150:Antipsychotic Agents; D001463:Barbiturates; D006993:Hypnotics and Sedatives; D009125:Muscle Relaxants, Central; D001569:Benzodiazepines; D009020:Morphine