title: Dye-coupling in the neostriatum of the rat: I. Modulation by dopamine-depleting lesions.
abstract: Evidence from experiments performed in turtle and fish retina suggests that dopamine (DA) modulates the permeability of gap junctions. The present experiment was aimed at determining if DA has a similar role in the mammalian neostriatum. Adults rats received one of four treatments: unilateral electrolytic substantia nigra lesions, unilateral injection of 6-hydroxydopamine (6-OHDA) into the substantia nigra, unilateral neocortical aspiration, or no treatment. After 3-5 weeks, neostriata from both sides of the brain were prepared for in vitro intracellular recordings. Recorded neurons (N approximately 150) were filled with Lucifer Yellow (LY), a low molecular weight dye that crosses gap junctions. In animals with electrolytic nigral lesions, dye-coupling in the ipsilateral neostriatum occurred after 38% of the intracellular injections. After 6-OHDA lesions, 19% of the injections produced dye-coupling in the ipsilateral neostriatum. This difference may have been accounted for by the fact that electrolytic lesions produced a greater degree of DA loss than 6-OHDA injections. Both of these percentages contrast with the very small percentage of dye-coupling found in intact animals or in animals with neocortical lesions. Dye-coupling occurred only between medium-sized spiny cells. No morphological differences between dye-coupled and non-dye-coupled cells were observed with light microscopy. Overall, passive and active electrophysiological properties of dye-coupled and single neurons were similar. The results suggest that DA may function in the neostriatum to control permeability of gap junctions.
authors.affiliation: Mental Retardation Research Center, University of California, Los Angeles 90024.
authors.forename: C
authors.initials: C
authors.lastname: Cepeda
authors.forename: J P
authors.initials: JP
authors.lastname: Walsh
authors.forename: C D
authors.initials: CD
authors.lastname: Hull
authors.forename: S G
authors.initials: SG
authors.lastname: Howard
authors.forename: N A
authors.initials: NA
authors.lastname: Buchwald
authors.forename: M S
authors.initials: MS
authors.lastname: Levine
mesh_terms: D000200:Action Potentials; D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism / Q000502:physiology*; D004558:Electric Stimulation; D005456:Fluorescent Dyes; D006892:Hydroxydopamines; D007365:Intercellular Junctions / Q000502:physiology*; D007546:Isoquinolines; D008297:Male; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
chemical_list: D005456:Fluorescent Dyes; D006892:Hydroxydopamines; D007546:Isoquinolines; D016627:Oxidopamine; C017475:lucifer yellow; D004298:Dopamine