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ACTIONS OF DANTROLENE SODIUM ON CONTRACTIONS OF THE TIBIALIS ANTERIOR AND SOLEUS MUSCLES OF CATS UNDER CHLORALOSE ANAESTHESIA
Author(s) -
Nott M. W.,
Bowman W. C.
Publication year - 1974
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1974.tb00532.x
Subject(s) - dantrolene sodium , dantrolene , chloralose , chemistry , soleus muscle , tetanic stimulation , tibialis anterior muscle , muscle relaxation , anesthesia , stimulation , medicine , skeletal muscle , calcium , biochemistry , excitatory postsynaptic potential , receptor
SUMMARY 1. Dantrolene depresses the tension of directly or indirectly elicited twitches and tetaní of the tíbíalís anteríor and soleus muscles of cats under chloralose anaesthesia, without affecting the gross muscle action potentials. 2. The decrease in twitch tension is associated with slowed rates of rise of tension and of relaxation, but there is no change in the time to peak tension. The decrease in maximal tetanic tension is associated with a slowed rate of rise of tension, but there is no change in the rate of relaxation. It is concluded that dantrolene decreases the intensity of the active state, possibly by impairing the release of Ca 2+ from the sarcoplasmic reticulum. 3. The soleus muscle is slightly more resistant than the tibialis anterior muscle to the action of dantrolene, and maximal tetani of both muscles are much more resistant than twitches. 4. Adrenaline, theophylline and quazodine produce effects on the dantrolene‐depressed twitches that are proportionately the same as those produced on the control twitches; there is no evidence of a specific antagonistic effect of any of these drugs. 5. Tetanic stimulation of the tibialis anterior muscle but not the soleus muscle causes a temporary relief of the twitch depression produced by dantrolene.