Abstract
Using acutely isolated rat substantia nigra neurons, our previous studies indicated that sulfated cholecystokinin octapeptide (CCK-8) excites substantia nigra dopaminergic neurons by increasing the cationic conductance and that pertussis toxin-insensitive G proteins mediate CCK-8 induction of cationic currents. Gαq and Gα11 are expressed in various tissues, including the brain, and likely to mediate pertussis toxin-insensitive neural signal transductions. In the present study, two different experiments were performed to test the hypothesis that Gαq/11 mediates CCK-8 enhancement of the cationic conductance. First, we investigated the expression of Gαq and Gα11 mRNAs in CCK-8-responsive substantia nigra dopaminergic neurons by combining whole-cell patch-clamp recordings with a single-cell reverse transcriptase-polymerase chain reaction assay. After CCK-8-evoked cationic currents were recorded, cellular RNA was harvested from single neurons and used as a template for the subsequent reverse transcriptase-polymerase chain reaction analysis. Gαq and Gα11 mRNAs were present in all substantia nigra dopaminergic neurons that responded to CCK-8. Substantia nigra dopaminergic neurons were also internally perfused with the antibody raised against the common C-terminus of Gαq and Gα11 during whole-cell recordings. CCK-8 failed to induce cationic currents after dopaminergic neurons were dialyzed with the anti-Gαq/11 antibody. Our studies suggest that CCK-8 activation of the cationic conductance in substantia nigra dopaminergic neurons is transduced by Gαq and/or Gα11.
Original language | English |
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Pages (from-to) | 1060-1066 |
Number of pages | 7 |
Journal | Journal of Neurochemistry |
Volume | 66 |
Issue number | 3 |
DOIs | |
State | Published - 03 1996 |
Keywords
- Cationic currents
- Pertussis toxin-insensitive G proteins
- Single-cell reverse transcriptase-polymerase chain reaction assay
- Sulfated cholecystokinin octapeptide
- Whole-cell patch-clamp recordings