Inhibition of caffeine contractures of slow rat muscles by urea and its derivatives.
Contractures induced by rapid cooling of rat soleus muscles in the presence of low concentrations of caffeine (2-3 mmol.l-1) have been studied. Urea, methylurea and 1,3-dimethylurea inhibit reversibly these contractures as well as caffeine contractures (20 mmol.l-1, 30 degrees C) but do not affect twitches. This finding leads support to the idea of the existence of different mechanisms activating contraction in response to caffeine action or deplorization.
D000818:Animals; D002110:Caffeine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D003864:Depression, Chemical; D008782:Methylurea Compounds / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D009132:Muscles / Q000502:physiology; D051381:Rats; D014508:Urea / Q000494:pharmacology*
D008782:Methylurea Compounds; D002110:Caffeine; D014508:Urea