Naloxone blocks the induction of long-term potentiation in the lateral but not in the medial perforant pathway in the anesthetized rat.
The possible importance of opioid peptides in the induction of long-term potentiation (LTP) was investigated in the perforant path-granule cell system. A high-frequency train (400 Hz) was delivered to the lateral or medial perforant path, during push-pull perfusion of the dentate molecular layer with artificial cerebrospinal fluid (CSF) alone, or with CSF containing naloxone (10(-4) M). Naloxone effectively blocked the induction, but not the maintenance of LTP in the lateral perforant path, a putative proenkephalin system. Naloxone did not affect the production of LTP in the medial pathway. These findings suggest that activation of naloxone-sensitive receptors is necessary for the full expression of LTP in the lateral perforant pathway.
Bramham
C R
CR
Department of Physiology, University of Bergen, Norway.
Errington
M L
ML
Bliss
T V
TV
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D009270:Naloxone