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GABAB receptor modulation of Ca2+ currents in rat sensory neurones by the G protein G(0): antisense oligonucleotide studies.
Author(s) -
Campbell V,
Berrow N,
Dolphin A C
Publication year - 1993
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1993.sp019842
Subject(s) - microbiology and biotechnology , oligonucleotide , gabab receptor , microinjection , g protein , dorsal root ganglion , chemistry , biology , agonist , receptor , biochemistry , anatomy , dna , dorsum
1. Calcium channel currents (IBa) were recorded in cultured dorsal root ganglion neurones (DRGs), 24‐32 h after microinjection with 20‐mer phosphorothioate antisense oligonucleotides complementary either to a G alpha o or a G alpha i unique sequence, or with a nonsense sequence. 2. The ability of the GABAB agonist (‐)‐baclofen (50 microM) to inhibit IBa was examined. The maximum peak current was inhibited by 35.3 +/‐ 4.0% (n = 11) in control non‐injected cells, and by 38.1 +/‐ 2.6% (n = 11) and 34.8 +/‐ 4.2% (n = 5) in nonsense‐ and G alpha i oligonucleotide‐injected cells. Following G alpha o oligonucleotide injection, (‐)‐baclofen inhibited IBa by 21.0 +/‐ 3.2% (n = 19). 3. Confocal immunocytochemical localization of G alpha o showed prominent staining at the plasma membrane in control DRGs, and this was also present in G alpha i and nonsense oligonucleotide‐injected cells. The G alpha o staining at the plasma membrane was reduced by 76% in G alpha o oligonucleotide‐injected cells. In contrast, confocal immunocytochemical localization of G alpha i showed immunostaining in the membrane and cytoplasm of control, G alpha o‐ and nonsense‐injected DRGs, whereas this was depleted by 68% in G alpha i oligonucleotide‐injected cells. 4. These results indicate that the GABAB receptor couples to voltage‐sensitive calcium channels via the G protein G(o) and not Gi, and that antisense oligonucleotides can be used to deplete G proteins in DRGs.