Inner plexiform circuits in the carp retina: Effects of cholinergic agonists, GABA, and substance P on the ganglion cells

R. D. Glickman, A. R. Adolph, J. E. Dowling

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


The effects on ganglion celllight responses and spontaneous activity of neuro-transmitter candidates, applied by nebulizer spray and iontophoresis, were studied in the isolated carp retina. ACh, GABA, and substance P had strong effects on the ganglion cells; dopamine and the amino acids aspartate, glutamate, and glycine had only weak effects. ACh and substance P exerted their actions even when synaptic transmission was blocked by cobalt chloride, suggesting postsynaptic receptors for those agents on the ganglion cell membrane. The 3 amino acids and dopamine do not appear to act directly on the ganglion cells. The pharmacological sensitivity of ganglion cells was correlated with their physiological response type. About three-quarters of ON/OFF and half of other transiently responding ganglion cells were excited by micromolar concentrations of cholinergic agonists; most ON-center sustained ganglion cells were insensitive. The light response of some of the ACh-sensitive cells could be suppressed by cholinergic antagonists. Substance P generally excited ganglion cells with an ON-component in their light response. GABA inhibited cells of all response types, but affected least the OFF-center tonic cells. In view of these observations, and of corroborating histological evidence, we propose that ACh, GABA, and substance P are neurotransmitters that are released by amacrine cells and affect receptors located on ganglion cells.

Original languageEnglish (US)
Pages (from-to)81-99
Number of pages19
JournalBrain Research
Issue number1
StatePublished - Feb 18 1982
Externally publishedYes


  • GABA
  • carp ganglion cells
  • carp retina
  • inner plexiform circuits
  • substance P

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology


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