Nitric oxide-stimulated increase in intracellular cGMP modulates gap junction coupling in rat neocortex.
In the present study we demonstrate that gap junction coupling between developing layer II/III pyramidal cells in rat sensorimotor cortex is strongly modified by the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) system. Dye coupling was revealed by intracellular injection of the gap junction-permeable tracer neurobiotin into single neurones. Following incubation of slices with sodium nitroprusside, a source of NO, the size of dye-coupled cell clusters was significantly reduced. In many cases, 2-3 cells remained strongly dye-coupled. These effects were blocked by intracellular injection of the guanylyl cyclase inhibitor cystamine and mimicked by both application of the membrane-permeant cGMP analogue 8-Br-cGMP and intracellular injection of cGMP. cGMP injection also induced a 60% increase in neuronal input resistance. These results indicate that NO modulates gap junction coupling in the developing neocortex via stimulation of guanylyl cyclase.
Rörig
B
B
Department of Physiology, University of Munich, Germany.
Sutor
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B
D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D017629:Gap Junctions / Q000187:drug effects*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
C070614:neurobiotin; D009599:Nitroprusside; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D001710:Biotin; D006152:Cyclic GMP