DESENSITIZATION BY TERBUTALINE OF β‐ADRENOCEPTORS IN THE GUINEA‐PIG SOLEUS MUSCLE: BIOCHEMICAL ALTERATIONS ASSOCIATED WITH FUNCTIONAL CHANGES

Article date: June 1982

By: T. BUUR, T. CLAUSEN, E. HOLMBERG, U. JOHANSSON, B. WALDECK in Volume 76, Issue 2, pages 313-317

The effects of adrenaline and terbutaline on cyclic adenosine 3′,5′‐monophosphate (cyclic AMP) content, 22Na‐efflux, 42K‐influx and subtetanic contractions have been assessed in soleus muscles isolated from guinea‐pigs which had been maintained on food with or without terbutaline for 5 days.

Terbutaline and adrenaline increased cyclic AMP content and suppressed subtetanic contractions, and regression analysis indicates a statistically significant correlation between these two effects (P<0.01).

In muscles obtained from terbutaline‐treated animals, the effects of terbutaline and adrenaline on cyclic AMP content, active Na‐K‐transport and subtetanic contractions were all considerably suppressed, but insulin stimulated 22Na‐efflux and affected subtetanic contractions to the same extent as in the muscles obtained from the control group.

The results suggest that terbutaline treatment leads to a reduction in the number of β2‐adrenoceptors in skeletal muscle or an impairment of their function.

The results provide further support for the idea that the effect of adrenaline or insulin on skeletal muscle contractions is the outcome of stimulation of active Na‐K‐transport.

The effects of adrenaline and terbutaline on cyclic adenosine 3′,5′‐monophosphate (cyclic AMP) content, 22Na‐efflux, 42K‐influx and subtetanic contractions have been assessed in soleus muscles isolated from guinea‐pigs which had been maintained on food with or without terbutaline for 5 days.

Terbutaline and adrenaline increased cyclic AMP content and suppressed subtetanic contractions, and regression analysis indicates a statistically significant correlation between these two effects (P<0.01).

In muscles obtained from terbutaline‐treated animals, the effects of terbutaline and adrenaline on cyclic AMP content, active Na‐K‐transport and subtetanic contractions were all considerably suppressed, but insulin stimulated 22Na‐efflux and affected subtetanic contractions to the same extent as in the muscles obtained from the control group.

The results suggest that terbutaline treatment leads to a reduction in the number of β2‐adrenoceptors in skeletal muscle or an impairment of their function.

The results provide further support for the idea that the effect of adrenaline or insulin on skeletal muscle contractions is the outcome of stimulation of active Na‐K‐transport.

DOI: 10.1111/j.1476-5381.1982.tb09222.x

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