Abstract
Whole-cell patch-clamp recordings were used to study Ba2+ currents through voltage-dependent Ca2+ channels in dorsal root ganglion X mouse neuroblastoma hybrid (F-11) cells. Opioid agonists selective for either μ (Tyr-D-Ala-Gly-Mephe-Gly-ol; DAMGO) or (Tyr-D-Pen-Gly-Phe-D-Pen-OH; DPDPE) receptors inhibited high-threshold Ba2+ currents. The inhibition was reversible, naloxone-sensitive, and dose-dependent. The inhibitory effects of both DAMGO and DPDPE were blocked by pretreatment of the cells with pertussis toxin (PTX) as well as by brief exposure to the sulfhydryl alkylating agent, N-ethylmaleimide (NEM). The N-type Ca2+ channel antagonist ω-conotoxin GVIA (ω-CTX GVIA) irreversibly inhibited high threshold Ba2+ currents by 66% and blocked the inhibitory effect of DAMGO or DPDPE. In contrast, the L- type Ca2+ channel blocker nifedipine inhibited high threshold Ba2+ currents by 15% and failed to block the inhibitory effect of DAMGO or DPDPE. These results demonstrate that μ and δ opioid receptors are negatively coupled to N-type Ca2+ channels via PTX- and NEM-sensitive GTP-binding proteins in F-11 cells.
Original language | English (US) |
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Pages (from-to) | 66-71 |
Number of pages | 6 |
Journal | Brain research |
Volume | 766 |
Issue number | 1-2 |
DOIs | |
State | Published - Aug 22 1997 |
Keywords
- F-11 cell
- High threshold Ba current
- N-type Ca channel
- μ and δ opioid receptor
ASJC Scopus subject areas
- General Neuroscience
- Molecular Biology
- Clinical Neurology
- Developmental Biology