Possible involvement of the spinal substance P system in pilocarpine-induced scratching in mice.
IT administration of pilocarpine in the spinal subarachnoid space of mice produced a dose-related hindlimb scratching. When coadministered with substance P IT, the pilocarpine-induced scratches were enhanced by high doses of substance P but not by subthreshold doses. This characteristic behavioral response was inhibited dose dependently by IT coadministration of spantide [D-Arg1, D-Trp7,9,Leu11] substance P. Significant antagonistic effects of [D-Phe7,D-His9] substance P (6-11), a selective antagonist for substance P receptors, and substance P (1-7), a substance P N-terminal fragment, were observed against the pilocarpine-induced scratching. Pretreatment with substance P antiserum resulted in the reduction of the response to pilocarpine. When coadministered IT with pilocarpine, atropine potently inhibited pilocarpine-induced scratching. These results demonstrate that not only muscarinic receptors but also substance P-containing neurons in the mouse spinal cord may be involved in elicitation of the scratching behavior following IT injection of pilocarpine.
Sakurada
T
T
Department of Pharmacology, Tohoku College of Pharmacy, Sendai, Japan.
Manome
Y
Y
Tan-No
K
K
Matsunaga
Y
Y
Sakurada
S
S
Kisara
K
K
D000344:Afferent Pathways / Q000187:drug effects; D000818:Animals; D007106:Immune Sera / Q000494:pharmacology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000187:drug effects*; D010446:Peptide Fragments / Q000494:pharmacology; D010862:Pilocarpine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D013116:Spinal Cord / Q000502:physiology*; D013373:Substance P / Q000031:analogs & derivatives / Q000276:immunology / Q000494:pharmacology / Q000502:physiology*
D007106:Immune Sera; D010446:Peptide Fragments; D010862:Pilocarpine; D013373:Substance P; C036877:substance P (1-7)