Role of calcium-calmodulin-dependent protein kinase II in modulation of sensorimotor synapses in Aplysia.
The Ca2+-calmodulin-dependent protein kinase II (CaMKII) inhibitor, [1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazi ne) (KN-62), was used to investigate the role of CaMKII in synaptic transmission and serotonin (5-HT)-induced facilitation in Aplysia. Application of KN-62 (10 microM) by itself increased the amplitude of excitatory postsynaptic potentials (EPSPs) at sensorimotor synapses in pleural-pedal ganglia. Moreover, in the presence of KN-62, 5-HT-induced short-term facilitation was attenuated. Application of KN-62 by itself slightly increased the duration of action potentials in isolated sensory neuron somata but did not block spike broadening produced by 5-HT. KN-62 had no effect on excitability of isolated sensory neuron somata nor did it block 5-HT-induced enhancement of excitability. These results indicate that the attenuation of short-term facilitation by KN-62 is not due to modulation of the membrane currents contributing to 5-HT-induced spike broadening or enhancement of excitability. Rather, these data are consistent with the hypothesis that CaMKII contributes to the regulation of sensorimotor connections and that it has a role in spike-duration-independent processes contributing to short-term facilitation.
Nakanishi
K
K
Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, 77225, USA.
Zhang
F
F
Baxter
D A
DA
Eskin
A
A
Byrne
J H
JH
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001048:Aplysia; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005071:Evoked Potentials / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology; D013569:Synapses / Q000502:physiology*
D004791:Enzyme Inhibitors; D012701:Serotonin; C063302:KN 62; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases