The effects of decentralization on substance P-immunoreactivity in the anterior major pelvic ganglion of the male guinea pig.
The anterior major pelvic ganglion (AMPG) of the male guinea pig possesses a substance P (SP)-immunoreactive peri-neuronal plexus. Selective nerve transections involving the principal inputs of the AMPG, the hypogastric and pelvic nerves, indicate that the SP-immunoreactive peri-neuronal plexus is derived from multiple sources: an extrinsic source involving both the hypogastric and pelvic nerves, and another source (possibly the projections of small intensely fluorescent cells). SP-immunoreactivity (IR) is not normally present in the neuronal perikarya of the AMPG. Evidence is presented that suggests the absence of SP-IR is due to an active suppression of SP-synthesis. This seems to be achieved by a trans-synaptic mechanism involving the hypogastric nerve which, after transection, leads to the appearance of neuronal perikarya exhibiting SP-IR (less than 1% of the total neuronal population of the AMPG). Up to 65% of the neuronal perikarya of the AMPG have the ability to synthesize SP, as demonstrated by SP-IR after 24 h in vitro. A more potent factor in the down-regulation of SP synthesis seems to be exerted by the pelvic genito-urinary organs, especially the prostate.
Dhami
D
D
Faculty of Medicine, University of Southampton, UK.
Mitchell
B S
BS
D000818:Animals; D001345:Autoradiography; D002470:Cell Survival; D003078:Colchicine / Q000494:pharmacology; D003714:Denervation; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006168:Guinea Pigs; D007001:Hypogastric Plexus / Q000502:physiology*; D008297:Male; D009424:Nervous System Physiological Phenomena; D009474:Neurons / Q000502:physiology; D010388:Pelvis / Q000294:innervation*; D013373:Substance P / Q000378:metabolism*
D013373:Substance P; D003078:Colchicine