The effect of protein kinase C stimulator and inhibitor on cochlear potentials in the guinea pig.
To determine a possible role of protein kinase C (PKC) in the cochlear, the effects of a PKC stimulator (phorbol-12-myristate-13-acetate; PMA), an inactive analogue of PKC stimulator (4 alpha-phorbol-12,13-didecanoate; 4 alpha-PDD) and a PKC inhibitor (D-sphingosine) on cochlear potentials were examined in the guinea pig. The perilymphatic perfusion with PMA (3 x 10(-6) M) produced an increase in compound action potential (CAP) amplitude and no change in N1 latency, the amplitudes of negative summating potential (-SP), cochlear microphonics (CM) and endocochlear potential (EP). The perfusion with 4 alpha-PDD (3 x 10(-6) M) did not change the sound-evoked cochlear potentials and the EP. The perfusion with D-sphingosine (10(-5) M) produced a decrease in CAP amplitude and no change in N1 latency and the amplitudes of -SP, CM and EP. The results suggest that PKC may be involved in the mechanism underlying the CAP generation.
Kitano
I
I
Department of Otolaryngology, Nara Medical University, Japan.
Nario
K
K
Mori
N
N
Matsunaga
T
T
D000161:Acoustic Stimulation; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D003051:Cochlea / Q000187:drug effects* / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D006168:Guinea Pigs; D006199:Hair Cells, Auditory, Inner / Q000166:cytology / Q000187:drug effects; D010477:Perfusion; D010703:Phorbol Esters / Q000494:pharmacology; D011493:Protein Kinase C / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013110:Sphingosine / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004791:Enzyme Inhibitors; D010703:Phorbol Esters; C008876:phorbol-12,13-didecanoate; D011493:Protein Kinase C; D013110:Sphingosine; D013755:Tetradecanoylphorbol Acetate