title: Overall distribution of substance P-containing nerves in the wall of the cerebral arteries of the guinea pig and its origins.
abstract: The overall distribution of substance P-like immunoreactivity (SPI) in the wall of the cerebral arteries and their origins were investigated in the guinea pig by using whole-mounts. Two types of SPI fibers were seen: one forming dense fiber bands and located among the periadventitial nerves, and the other forming a meshwork. The SPI fibers located in the periadventitial nerves often leave these nerves to form a meshwork of SPI fibers of varying density according to the diameter or location of the blood vessels. The present study suggests that: (1) SPI fibers located on the circle of Willis and its branches originate from SPI cells in the trigeminal ganglion; (2) SPI fibers of the rostral one-third of the basilar artery originate partly from trigeminal SPI cells; and (3) SPI fibers in the caudal two-thirds of the basilar artery originate exclusively from other SPI cells, apart from the trigeminal ganglion.
mesh_terms: D000818:Animals; D001488:Basilar Artery / Q000294:innervation; D002536:Cerebral Arteries / Q000294:innervation*; D002941:Circle of Willis / Q000294:innervation; D005455:Fluorescent Antibody Technique; D006168:Guinea Pigs; D008856:Microscopy, Fluorescence; D013373:Substance P / Q000378:metabolism*; D014711:Vertebral Artery / Q000294:innervation
chemical_list: D013373:Substance P