Ultrastructural evidence for the coexistence of calcitonin gene-related peptide and substance P in secretory vesicles of peripheral nerves in the guinea pig.
Using double immunogold staining procedures, calcitonin gene-related peptide (CGRP)-like and substance P (SP)-like immunoreactivities were localized at the ultrastructural level to guinea pig trigeminal ganglia, dorsal root ganglia and peripheral nerve fibres associated with the vascular system. CGRP-like and SP-like immunoreactivities were found consistently in large granular secretory vesicles (70-100 nm in diameter), and both peptide immunoreactivities were co-localized to the same vesicle in both sensory ganglion cells and within axons and their terminals in the adventitia and adventitial-medial border of the superior mesenteric artery. These results suggest that CGRP and SP are co-stored and may be released together from peripheral axons in the guinea pig.
D000818:Animals; D015740:Calcitonin Gene-Related Peptide; D003594:Cytoplasmic Granules / Q000648:ultrastructure*; D006046:Gold; D006168:Guinea Pigs; D006651:Histocytochemistry; D007163:Immunosorbent Techniques; D008854:Microscopy, Electron; D009419:Nerve Tissue Proteins / Q000032:analysis*; D010525:Peripheral Nerves / Q000648:ultrastructure*; D013373:Substance P / Q000032:analysis*
D009419:Nerve Tissue Proteins; D013373:Substance P; D006046:Gold; D015740:Calcitonin Gene-Related Peptide