Soluble guanylyl cyclase is localized at the neuromuscular junction in human skeletal muscle.

Soluble guanlylyl cyclase (sGC) seems to be involved in mechanisms for rapid translation of electrical and chemical signals at the neuromuscular junction. To explore the cellular localization of the alpha2, alpha1 and beta1 subunits of sGC, we studied normal and denervated human muscle biopsies immunohistochemically using antibodies directed against the alpha2 and alpha1/beta1 subunits of sGC and performed double labellings with alpha-bungarotoxin. Confocal imaging could localize the alpha2 and alpha1/beta1 subunits of sGC at neuromuscular junctions and vessels and the subunits remained concentrated at neuromuscular junctions following denervation. The presence of sGC at neuromuscular junctions and at vessels suggests sGC could serve as a postsynaptic second messenger for fine tuning of nerve-muscle interaction and dynamic regulation of intramuscular blood flow.