Forskolin blocks the transient K current of rat cerebellar granule neurons.
The action of forskolin (FSK) on voltage-activated K currents was investigated in cerebellar granule cells. FSK reversibly inhibited both A-type (IA) and non-inactivating K currents. IA blockade was more precisely characterized. This effect of FSK was shown to be voltage- and concentration-dependent with an IC50 of 19 microM at +50 mV. 1,9-Dideoxyforskolin (1,9-ddxFSK), a derivative of FSK that does not activate adenylate cyclase, specifically blocked IA, while cAMP-increasing agents had no direct effect on the K currents. The possibility that the non-cAMP mediated effect of FSK occurs through a channel-blocking mechanism and its eventual implications for neuronal excitability are discussed.
Zerr
P
P
Laboratoire de Neurobiologie Cellulaire, UPR 9009 CNRS, Strasbourg, France.
Feltz
A
A
D000818:Animals; D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D005576:Colforsin / Q000031:analogs & derivatives / Q000494:pharmacology*; D000242:Cyclic AMP / Q000819:agonists; D004553:Electric Conductivity; D004594:Electrophysiology; D009474:Neurons / Q000502:physiology*; D009479:Neuropeptides / Q000494:pharmacology; D009994:Osmolar Concentration; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011188:Potassium / Q000037:antagonists & inhibitors / Q000502:physiology*; D051381:Rats; D013997:Time Factors
C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D005576:Colforsin; D000242:Cyclic AMP; C047983:1,9-dideoxyforskolin; D011188:Potassium