[Neuromuscular junctions of the rat diaphragm in experimental hypoparathyroidism]

The ultrastructure of neuro-muscular junctions in diaphragm muscle underwent certain changes in the course of experimental hypothyrosis (thermal destruction of a part of parathyroid gland). The most pronounced structural changes were observed in maximum hypocalcemia (7 days after the operation). There was a correlation between the pattern of a transmitter release and some parameters of vesicular apparatus (the number and volume distribution of synaptic vesicles). These effects suggest that hypoparathyroidism causes an increase in calcium content in axon terminals.