Development of G protein-mediated Ca2+ channel regulation in mouse embryonic stem cell-derived neurons.
Besides other mechanisms, the influx of Ca2+ into embryonic neurons controls growth and differentiation processes. To study the expression and regulation of voltage-gated Ca2+ channels during early neurogenesis, we measured whole-cell Ca2+ currents (I(Ca)) in neurons developing from pluripotent embryonic stem cells. Various receptor agonists, including somatostatin and baclofen, reversibly inhibited I(Ca) in embryonic stem cell-derived neurons. The effects of somatostatin and baclofen were abolished by pretreatment of cells with pertussis toxin and mimicked by intracellular infusion of guanosine 5'-O-(3-thiotriphosphate), suggesting the involvement of pertussis toxin-sensitive G proteins in I(Ca) inhibition. Investigations at different stages of neuronal differentiation showed that somatostatin efficiently suppressed L- and N-type Ca2+ channels in immature as well as mature neurons. In contrast, inhibition of L- and N-type channels by baclofen was rarely observed at the early stage. In terminally differentiated neurons, responses to baclofen were as prominent as those to somatostatin but were confined to N-type Ca2+ channels. The stage-dependent sensitivity of voltage-gated Ca2+ channels to somatostatin and baclofen was not due to differential expression of G alpha(o) isoforms, as revealed by reverse transcription-polymerase chain reaction and immunofluorescence microscopy. These findings demonstrate that specific neurotransmitters such as somatostatin regulate voltage-gated Ca2+ channels via G proteins during the early stages of neurogenesis, thus providing a mechanism for the epigenetic control of neuronal differentiation.
Strübing
C
C
Institut für Pharmakologie, Universitätsklinikum Benjamin Franklin, FU Berlin, Germany.
Rohwedel
J
J
Ahnert-Hilger
G
G
Wiedenmann
B
B
Hescheler
J
J
Wobus
A M
AM
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000096:biosynthesis / Q000187:drug effects / Q000502:physiology*; D002454:Cell Differentiation; D002460:Cell Line; D004553:Electric Conductivity; D004622:Embryo, Mammalian; D019204:GTP-Binding Proteins / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006706:Homeostasis; D017275:Isradipine / Q000494:pharmacology; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology; D013004:Somatostatin / Q000494:pharmacology; D013111:Spider Venoms / Q000494:pharmacology; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D020867:omega-Agatoxin IVA; D020866:omega-Conotoxin GVIA; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010455:Peptides; D013111:Spider Venoms; D020867:omega-Agatoxin IVA; D020960:omega-Conotoxins; C075851:omega-conotoxin-MVIIC; D013004:Somatostatin; D020866:omega-Conotoxin GVIA; D019204:GTP-Binding Proteins; D001418:Baclofen; D017275:Isradipine