Cycloheximide abolishes pertussis toxin-induced increase in glutamate release from cerebellar granule neurones.
Release of glutamate from cerebellar granule neurones was stimulated either by adding 50 mM K+ to normal Krebs medium, or by adding 5 mM Ca2+ to neurones continuously depolarised with 50 mM K+ in the absence of Ca2+. Pre-incubation of neurones for 16 h with pertussis toxin (PTX) increased the stimulated glutamate release in both K(+)-stimulated and continuously depolarised neurones. Under both conditions, the PTX-induced increase in release was abolished by cycloheximide. In contrast, in the presence of cycloheximide, PTX still prevented the GABAB agonist (-)-baclofen from inhibiting glutamate release. These results suggest that G-protein ADP-ribosylation by PTX in cerebellar granule neurones may increase synthesis of a protein associated with the L-type calcium channel.
Cullen
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GP
Department of Pharmacology, Royal Free Hospital School of Medicine, London, UK.
Huston
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E
Dolphin
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AC
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology*; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D037342:Pertussis Toxin; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D010566:Virulence Factors, Bordetella / Q000037:antagonists & inhibitors* / Q000494:pharmacology
D005971:Glutamates; D010566:Virulence Factors, Bordetella; D018698:Glutamic Acid; D003513:Cycloheximide; D037342:Pertussis Toxin; D001418:Baclofen; D011188:Potassium; D002118:Calcium