An in vitro method for the study of beta-receptor mediated effects on slow contracting skeletal muscle.
The soleus muscle of a guinea-pig was dissected out under pentobarbitone anaesthesia and mounted on a holder in an organ bath containing Krebs solution. The tendon was attached to a force transducer and subtetanic contractions were evoked by electrical field stimulation (0.5 ms pulses at 10-12 Hz for 1.5 or 3 s every 22 s). The experiments were performed at 37 degrees. Terbutaline, a selective agonist at beta2-adrenoceptors, reduced the force of subtetanic contractions in a dose-dependent manner, the EC50 being 0.2 muM. The reduction was due to a lessened degree of fusion. The results conform to previous in vivo studies.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D011941:Receptors, Adrenergic / Q000187:drug effects*; D013726:Terbutaline / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D011941:Receptors, Adrenergic; D013726:Terbutaline