Rapid appearance of intraventricularly administered neuropeptides in the peripheral circulation.
125I-Labeled cholecystokinin octapeptide ([125I]CCK-OP) diffuses rapidly by a non-carrier-mediated mechanism into the peripheral blood following injection into the lateral ventricle of a rabbit. In contrast, no [125I]CCK-OP was observed in the CSF following intravenous injection. This unidirectional free transport mechanism from CSF to blood may apply to other neuropeptides as well.
D000818:Animals; D001067:Appetite Depressants / Q000008:administration & dosage*; D002766:Cholecystokinin / Q000008:administration & dosage* / Q000097:blood / Q000134:cerebrospinal fluid; D007276:Injections, Intraventricular; D007457:Iodine Radioisotopes; D007700:Kinetics; D010446:Peptide Fragments / Q000008:administration & dosage* / Q000097:blood / Q000134:cerebrospinal fluid; D011817:Rabbits; D012844:Sincalide
D001067:Appetite Depressants; D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D002766:Cholecystokinin; D012844:Sincalide