title: Met-enkephalin, age and anatomy: a microiontophoretic study in the hippocampus.
abstract: Met-enkephalin, administered microiontophoretically, produced a greater increase in firing in cells in area CA 3-4 in the hippocampus of both young and aged Fisher 344 rats than it did in the CA 1 area. Furthermore, the effect of met-enkephalin on neuronal firing rates was not as great in old rats as it was in young rats. Finally, 20-40 nA of met-enkephalin produced an increase in firing in old rats that was equivalent to the difference (2.5 spikes/sec) in baseline firing between old (2.6 spikes/sec) and young rats (5.1 spikes/sec).
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D007478:Iontophoresis; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011916:Rats, Inbred F344; D011976:Receptors, Muscarinic / Q000502:physiology
chemical_list: D011976:Receptors, Muscarinic; D004744:Enkephalin, Methionine