Patients with Lambert-Eaton myasthenic syndrome (LEMS) possess antibodies to voltage-gated calcium channels on presynaptic lower motor neurons, which decreases calcium influx and acetylcholine release to postsynaptic skeletal muscle cells.
In some patients, malignancies (eg, small cell lung cancer) trigger production of these antibodies, resulting in paraneoplastic LEMS Patients present with progressive proximal muscle weakness that improves with repetitive motion and exercise.
The postsynaptic membrane potential (Choice D) may be decreased in LEMS secondary to the decreased presynaptic release of acetylcholine. = WRONG ANS.
submitted by โstep420(32)
Person has Lambert-Eaton syndrome (hx of lung cancer, and muscle activity that is better with use.
Presynaptic Ca2+ antibodies prevent the release of AcH presynaptically because the antibodies prevent the depolarization within the cell and prevents synaptic vessels of ACh from leaving.