Abstract
Peripheral nerve, muscle, and synaptic physiology in 33 patients with pulmonary carcinoma was studied by means of clinical neurological examination in all and conduction velocity measurements of motor and sensory nerves in 19. Histological and histochemical examination of biopsied intercostal muscle and study of the physiology of the motor end‐plate using intracellular microelectrodes were also performed in some. The observations were compared with those in a group of 9 patients with noncarcinomatous lung disease.
Polyneuropathy was more frequent in patients with carcinoma of the lung than without. Histological examination of muscle revealed only slight structural changes, not different from those in patients without carcinoma. Resting membrane potentials were similar in the two groups. The mean frequency of miniature end‐plate potentials (mepps) in bathing solution containing 5 mM K^+^ was higher in 13 patients with pulmonary carcinoma than in 5 noncarcinomatous patients. Mean mepp amplitudes were similar. Muscles from patients with pulmonary carcinoma had a diminished ability to increase transmitter release in presynaptic depolarization performed with bathing solution containing 20 mM K^+^. The quantum content calculated was less in 1 carcinoma patient than in 2 patients without carcinoma.