Heterologous expression of metabotropic glutamate receptors in adult rat sympathetic neurons: subtype-specific coupling to ion channels.
A novel heterologous expression system was used to examine the coupling of metabotropic glutamate receptors (mGluRs) to neuronal voltage-gated ion channels. Cytoplasmic injection of mGluR2 cRNA into adult rat sympathetic neurons resulted in the expression of receptors that negatively coupled to N-type Ca2+ channels through a pertussis toxin-sensitive pathway. Injection of mGluR1 alpha cRNA resulted in the expression of receptors that inhibited M-type K+ channels via a pertussis toxin-insensitive pathway. Coupling was restricted to specific transduction elements and effectors, since mGluR2 did not inhibit M channels and mGluR1 alpha had minimal effects on Ca2+ channels. These findings demonstrate that heterologously expressed, and thus unambiguously identified, mGluR subtypes modulate specific neuronal ion channels through discrete signal transduction pathways.
Ikeda
S R
SR
Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta 30912, USA.
Lovinger
D M
DM
McCool
B A
BA
Lewis
D L
DL
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology; D004553:Electric Conductivity; D005260:Female; D015870:Gene Expression; D018014:Gene Transfer Techniques; D007473:Ion Channels / Q000502:physiology*; D007700:Kinetics; D008297:Male; D009474:Neurons / Q000378:metabolism*; D037342:Pertussis Toxin; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology; D018075:RNA, Complementary / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics*; D015398:Signal Transduction; D017783:Superior Cervical Ganglion / Q000166:cytology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D007473:Ion Channels; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D018075:RNA, Complementary; D018094:Receptors, Metabotropic Glutamate; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin