Effects of cholinergic agonists on immature rat hippocampal neurons

Laura J. Reece, Philip A Schwartzkroin

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We have investigated the effects of acetylcholine (ACh) and the cholinergic agonist carbachol on several cell types in the developing rat hippocampus. Pyramidal cells were responsive to cholinergic applications on the first day examined (postnatal day 2), indicating that postsynaptic cholinoceptivity develops early, perhaps before functional cholinergic innervation is present. These drugs, which induce a membrane depolarization and a conductance decrease in mature pyramidal cells, had similar effects (both magnitude and pharmacology) on most immature neurons. However, a minority of cells in immature tissue exhibited decreased input resistance (Rin) during the cholinergic-induced depolarization. This response is likely a product of cholinergic action on local circuit neurons; non-pyramidal-type cells from animals as young as 8 days demonstrated excitatory responses to application of cholinergic agonists. The study revealed a number of other features of immature cells which may have functional significance. Lucifer yellow injections showed significant dye coupling among CA3 (but not CA1) pyramidal cells in immature tissue, suggesting close metabolic and/or electrotonic coupling between those cells during development. Mature CA3 cells showed less dye coupling, but increased anomalous rectification, and longer time constant. Developmental changes in intrinsic cell properties, coupled to alterations in local circuit interactions, may alter tissue responsiveness to neurotransmitters such as acetylcholine, even if the receptor-mediated drug action remains stable.

Original languageEnglish (US)
Pages (from-to)29-42
Number of pages14
JournalDevelopmental Brain Research
Volume60
Issue number1
DOIs
StatePublished - May 20 1991
Externally publishedYes

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Cholinergic Agonists
Neurons
Cholinergic Agents
Pyramidal Cells
Coloring Agents
Carbachol
Cholinergic Receptors
Pharmaceutical Preparations
Neurotransmitter Agents
Hippocampus
Pharmacology
Injections
Membranes

Keywords

  • Acetylcholine
  • Hippocampal slice
  • Local circuit neuron
  • Pyramidal cell

ASJC Scopus subject areas

  • Developmental Biology
  • Developmental Neuroscience

Cite this

Effects of cholinergic agonists on immature rat hippocampal neurons. / Reece, Laura J.; Schwartzkroin, Philip A.

In: Developmental Brain Research, Vol. 60, No. 1, 20.05.1991, p. 29-42.

Research output: Contribution to journalArticle

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