Serotonin facilitates synaptic plasticity in kitten visual cortex: an in vitro study.
We have addressed the role of serotonin-2C (5-HT2C) receptors in the development and maintenance of synaptic plasticity in the kitten visual cortex. In visual cortical slices, taken from 40- to 80-day-old kittens, bath application of serotonin markedly facilitated the induction of both long-term depression (LTD) and long-term potentiation (LTP). Field potential responses to white matter stimulation were recorded from layer IV after a regime of low frequency stimulation (LFS; 1 Hz, 15 min), which reliably induced LTP or LTD in younger kittens (less than 30 days of age). At 40-80 days, this protocol almost never induced LTD or LTP in layer IV. However, in 50% of the visual cortical slices studied in 40-80-day-old kittens, LTD or LTP was induced, if serotonin (1 or 10 microM) was co-applied with LFS. No such serotonin facilitation of long-term plasticity was ever detected in > 120-day-old animals, indicating that serotonin facilitates synaptic plasticity within a defined period of visual cortical development. Serotonergic 5-HT2C receptors are likely to contribute to the synaptic plasticity observed in layer IV, since mesulergine, an antagonist of the 5-HT2C receptor, completely blocked synaptic modifications induced by the combination of low frequency stimulation and serotonin application.
Kojic
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L
Department of Ophthalmology, University of British Columbia, Vancouver, Canada. kojic@ecc.ubc.ca
Gu
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Douglas
R M
RM
Cynader
M S
MS
D000375:Aging / Q000502:physiology; D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000502:physiology; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology / Q000502:physiology*; D014793:Visual Cortex / Q000187:drug effects / Q000502:physiology*
D018377:Neurotransmitter Agents; D011985:Receptors, Serotonin; D012701:Serotonin