Measurement of substance P metabolites in rat CNS.
A procedure based on ion-exchange chromatography for chemical separation and radioimmunoassays for quantitation of substance P (SP), the SP(1-7), and C-terminal fragments, respectively, has been developed. The procedure allows the determination of these fragments in the presence of large (i.e., 50- to 100-fold) excess of parent compound. The chemical identity of isolated SP and fragments was studied with preparative electrophoresis on dilute agarose gel and with HPLC. The activity identified as SP(1-7) comigrated with the authentic standard whereas practically all activity isolated as C-terminal fragments comigrated with SP(5-11). The levels of C-terminal fragments in rat brain areas rich in SP and in spinal cord were 1-2% of those of parent compound. The levels of SP(1-7) were always higher, in the spinal cord markedly higher (three to five times). Postmortem storage of samples from brain and spinal cord indicated that SP(1-7) levels fell more rapidly than those of SP or C-terminal fragments.
Sakurada
T
T
Le Grevés
P
P
Stewart
J
J
Terenius
L
L
D000818:Animals; D002490:Central Nervous System / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004587:Electrophoresis, Agar Gel; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000378:metabolism*
D013373:Substance P