EEG evidence that morphine and an enkephalin analog cross the blood-brain barrier.
The ability of naltrexone but not methyl naltrexone to cross the blood-brain barrier (BBB) was used to provide a different approach for the demonstration that opiates can enter the brain. Cortical electroencephalographic (EEG) measurements were made in rats receiving peripheral (IP) injections of naltrexone or methyl naltrexone and morphine or an enkephalin analog [Tyr-D-Ala-Gly-MePhe-Met(O)-ol]. Naltrexone significantly blocked the EEG effects of morphine and the enkephalin analog, but methyl naltrexone failed to do so. The results provide biological evidence that an opiate peptide can cross the BBB to affect the activity of the brain.
VA Medical Center, New Orleans, LA.
A J
AJ
Kastin
M A
MA
Pearson
W A
WA
Banks
D000595:Amino Acid Sequence; D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin / Q000737:chemistry / Q000493:pharmacokinetics*; D004569:Electroencephalography; D009075:MSH Release-Inhibiting Hormone / Q000494:pharmacology; D008297:Male; D008969:Molecular Sequence Data; D009020:Morphine / Q000493:pharmacokinetics*; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds; D051381:Rats; D011919:Rats, Inbred Strains
D000644:Quaternary Ammonium Compounds; C032257:methylnaltrexone; D009271:Naltrexone; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D009020:Morphine; D009075:MSH Release-Inhibiting Hormone