Distribution of label after intrathecal administration of /sup 125/I-substance P in the rat

Journal Article · Sun Mar 01 04:00:00 EST 1987 · Peptides (Fayetteville, N.Y.); (United States)

DOI:https://doi.org/10.1016/0196-9781(87)90092-1· OSTI ID:6477053

Cridland, R A; Yashpal, K; Romita, V V; Gauthier, S; Henry, J L

Despite the widespread use of the intrathecal route for the administration of neuroactive agents, little is known about the penetration of these agents into the spinal cord. In the present study, /sup 125/I-substance P was injected via a spinal catheter to the thoracic or sacro-coccygeal spinal cord in the rat (350-400 g) anesthetized with urethane (2.5 g/kg). Spinal cords were removed rapidly at 1 or 10 min after injection and immediately frozen in CCl/sub 2/F/sub 2/. Frozen sections, 20 micron thick, were cut and mounted for autoradiography. Autoradiographs of transverse sections demonstrated that the label penetrated 700 to 1800 micron from the surface of the spinal cord at both levels. In longitudinal sections, this penetration extended about 0.5 cm rostrally and caudally from the site of injection. Serial autoradiographs of transverse sections showed a similar penetration rostro-caudally. In addition, venous blood samples were taken at 1, 6, 11 and 16 min after injection of the labelled peptide. Quantification of the radioactivity in the samples revealed that 0.8 to 3.5% of the total CPM injected had passed into the general circulation at these times. These data indicate that after intrathecal administration of radiolabelled substance P, the label penetrates into the grey matter of the spinal cord to presumed sites of action. They also suggest that the rostro-caudal extent of penetration is more localized than suggested from earlier studies which looked only at levels of radioactivity in pieces of whole spinal cord. Finally, our study has indicated that passage of label into the circulation is negligible at least for substance P.

• Research Organization: Allan Memorial Institute, Montreal, Quebec
• OSTI ID: 6477053
• Journal Information: Peptides (Fayetteville, N.Y.); (United States), Journal Name: Peptides (Fayetteville, N.Y.); (United States) Vol. 2; ISSN PPTDD
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
DISTRIBUTION
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
MAMMALS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDES
PROTEINS
RADIOISOTOPES
RATS
RODENTS
SPINAL CORD
TISSUE DISTRIBUTION
VERTEBRATES