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SELECTIVE DEVELOPMENT OF TOLERANCE TO β‐ADRENOCEPTOR AGONISTS IN SKELETAL MUSCLE AS COMPARED WITH AIRWAY SMOOTH MUSCLE FROM THE GUINEA‐PIG
Author(s) -
Holmberg E.,
Jeppsson A.B.,
Waldeck B.
Publication year - 1981
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.1440-1681.1981.tb00133.x
Subject(s) - terbutaline , isoprenaline , isometric exercise , in vivo , medicine , endocrinology , skeletal muscle , guinea pig , muscle relaxation , soleus muscle , extensor digitorum longus muscle , chemistry , biology , stimulation , asthma , microbiology and biotechnology
SUMMARY 1. Guinea‐pigs were fed with a diet containing terbutaline or placebo for 4–5 days. The trachea, soleus muscle and the extensor digitorum longus (EDL) from these animals were prepared for recording of isometric contractions in vitro. 2. After treatment with terbutaline in vivo , the response of the pilocarpine‐contracted trachea to terbutaline and isoprenaline was slightly suppressed with no change in maximum relaxation. 3. After treatment with terbutaline in vivo the maximum depression of the incomplete tetanic contractions of the soleus muscle brought about by terbutaline or isoprenaline was diminished by about 70%. The response of the EDL was also attenuated after previous treatment with terbutaline in vivo. 4. These data indicate a selective development of tolerance to the effects of β‐adrenoceptor agonists in skeletal muscle as compared with tracheal smooth muscle. 5. The present results provide an experimental analogue to the clinical observation that patients being treated with β‐adrenoceptor agonists become tolerant to the tremorogenic rather than to the bronchodilating effect.