Location of substance P-, bombesin-gastrin-releasing peptide, [Met5]enkephalin- and [Met5]enkephalin-Arg6-Phe7-like immunoreactivities in adult human sympathetic ganglia.

Indirect immunofluorescent methods were used to study peptides in human paravertebral sympathetic ganglia. [Met5]enkephalin, [Met5]enkephalin-Arg6-Phe7 and bombesin-gastrin-releasing peptide-like immunoreactivities were localized in varicose nerve fibers, which often formed basket-like networks around principal ganglion cells. Substance P-like immunoreactivity appeared frequently as solitary varicose nerve fibers and occasionally as networks. No immunolabeled cell bodies were discovered with any of the antisera used, including antibodies raised against molluscan cardioexcitatory peptide Phe-Met-Arg-Phe-NH2. The results demonstrate the presence of peptides within nerve fibers and terminals but not cell bodies of human paravertebral sympathetic ganglia. The localization suggests that the peptides have neurotransmitter or neuromodulator roles in the ganglia.