title: Developmental changes in serotonin actions in rat hippocampus.
abstract: Intracellular activity was recorded from neurons in immature rat hippocampal slices. The presence of intrinsic inhibitory synaptic potentials as well as responses to serotonin were assessed in slices of 1, 2 or 3 postnatal weeks of age. Young (1 week) cells had only a marginal hyperpolarizing response to serotonin and no detectable intrinsic inhibitory synaptic potentials. At 2 weeks of age neurons already expressed a fast IPSP (inhibitory postsynaptic potential). The responses to serotonin were different from those of adult cells in that they involved primarily a large decrease in input resistance with only small potential changes. In cells of this age serotonin caused a marked increase in spontaneous IPSP discharges and a blockade of a slow afterhyperpolarization. In 3-week-old rats the fast and slow components of the IPSP were present as in adult and the responses to serotonin included a large hyperpolarization associated with an increase in K conductance, a blockade of slow afterhyperpolarization and a blockade of a slow IPSP, as seen in adult cells. These results indicate that the complex pattern of reactivity to serotonin is differentially regulated in the developing brain.
authors.affiliation: Center for Neuroscience, Weizmann Institute, Rehovot, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Segal
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000375:Aging / Q000502:physiology*; D000818:Animals; D006624:Hippocampus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*
chemical_list: D012701:Serotonin