Muscle Plasticity and β2-Adrenergic Receptors: Adaptive Responses of β2-Adrenergic Receptor Expression to Muscle Hypertrophy and Atrophy

Abstract EN

We discuss the functional roles of β2-adrenergic receptors in skeletal muscle hypertrophy and atrophy as well as the adaptive responses of β2-adrenergic receptor expression to anabolic and catabolic conditions.

β2-Adrenergic receptor stimulation using anabolic drugs increases muscle mass by promoting muscle protein synthesis and/or attenuating protein degradation.

These effects are prevented by the downregulation of the receptor.

Endurance training improves oxidative performance partly by increasing β2-adrenergic receptor density in exercise-recruited slow-twitch muscles.

However, excessive stimulation of β2-adrenergic receptors negates their beneficial effects.

Although the preventive effects of β2-adrenergic receptor stimulation on atrophy induced by muscle disuse and catabolic hormones or drugs are observed, these catabolic conditions decrease β2-adrenergic receptor expression in slow-twitch muscles.

These findings present evidence against the use of β2-adrenergic agonists in therapy for muscle wasting and weakness.

Thus, β2-adrenergic receptors in the skeletal muscles play an important physiological role in the regulation of protein and energy balance.