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G αq/11 Mediates Cholecystokinin Activation of the Cationic Conductance in Rat Substantia Nigra Dopaminergic Neurons
Author(s) -
Wu Tony,
Wang HungLi
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.66031060.x
Subject(s) - substantia nigra , dopaminergic , cholecystokinin , neuroscience , chemistry , dopamine , medicine , endocrinology , biology , biochemistry , receptor
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. G αq and G α11 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 G αq/11 mediates CCK‐8 enhancement of the cationic conductance. First, we investigated the expression of G αq and G α11 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. G αq and G α11 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 G αq and G α11 during whole‐cell recordings. CCK‐8 failed to induce cationic currents after dopaminergic neurons were dialyzed with the anti‐G αq/11 antibody. Our studies suggest that CCK‐8 activation of the cationic conductance in substantia nigra dopaminergic neurons is transduced by G αq and/or G α11 .