Loss of extrasynaptic channel modulation by protein kinase C underlies the selection of serotonin responses in an identified leech neuron.
Pressure-sensitive (P) neurons contacted by serotonergic Retzius (R) neurons of the leech in culture selectively reduce a protein kinase C (PKC)-dependent cation response to serotonin and are innervated by the inhibitory, Cl(-)-dependent synapse seen in vivo. We have examined whether the reduction of extrasynaptic cation channel modulation is due to changes in sensitivity of the channels to second messenger. In inside-out membrane patches from single, uncontacted P cells in culture, cation channel activity was increased by rat brain PKC and cofactors. In contrast, the activity of cation channels in patches isolated from P cells paired with R cells was unaffected by PKC. These results demonstrate the loss of extrasynaptic channel modulation by PKC during synapse formation.
Centre for Research in Neuroscience, McGill University, Montreal, Quebec, Canada.
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D000818:Animals; D002412:Cations / Q000378:metabolism; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D007865:Leeches / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D011493:Protein Kinase C / Q000494:pharmacology / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure
D002412:Cations; D007473:Ion Channels; D012701:Serotonin; D011493:Protein Kinase C