Absence of decremental response in decentralized muscles of a myasthenic patient

Decentralized muscles of patients with upper motoneurone lesions may show anomalous responses to drugs acting on acetylcholine receptors. We compared the effects produced by repetitive nerve stimulation on normal and decentralized muscles of a patient with myasthenia gravis admitted to our Institute for a right hemiparesis. A myasthenic response was observed on the left (unaffected) deltoid muscle and a normal response on the opposite (paretic) side. It is suggested that decentralization might alter the functional properties of junctional receptors.