Brain uptake and the analgesic effect of oxytocin--its usefulness as an analgesic agent.
To establish the usefulness of oxytocin (OT) as an analgesic for women in delivery, the pharmacokinetic parameters and blood-brain barrier (BBB) permeability of [3H]OT were obtained using an intravenous injection technique or the internal carotid artery perfusion/capillary depletion (ICAP/CDM) method. Brain uptake of OT was similar to that of sucrose, plasma space marker, indicating that OT has a poor BBB permeability. Moreover, the analgesic effects of OT injected through the jugular vein on nociception were evaluated by the tail-flick method. The antinociceptive effects of OT injected at a dose of 0.2 mg/kg or 2 mg/kg were dose-dependent. In addition, the analgesic effects of OT on the CNS were unaffected by naloxone, a m-receptor antagonist. In a similar manner to the opioid system, OT may play a modulatory role in antinociception.
Kang
Y S
YS
College of Pharmacy, Sookmyung Women's University, Seoul, Korea. yskang@sdic.sookmyung.ac.krr
Park
J H
JH
D018712:Analgesics, Non-Narcotic / Q000493:pharmacokinetics*; D000818:Animals; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism*; D008297:Male; D010121:Oxytocin / Q000493:pharmacokinetics* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D018712:Analgesics, Non-Narcotic; D010121:Oxytocin