Avtor/Urednik		van Brederode, JFM; Rho, JM; Černe, R; Tempel, BL; Spain, WJ
Naslov		Evidence of altered inhibition in layer v pyramidal neurons from neocortex of Kcna 1-null mice
Tip		članek
Vir		Neuroscience
Vol. in št.		Letnik 103, št. 4
Leto izdaje		2001
Obseg		str. 921-9
Jezik		eng
Abstrakt		Mice lacking the potassium channel subunit KCNAI exhibit a severe epileptic phenotype beginning at an early postnatal age. The precise cellular physiological substrates for these seizures are unclear, as is the site of origin. Since KCNA1 mRNA in normal mice is expressed in the neocortex, we asked whether neurons in the neocortex of three to four week-old Kcnal-null mutants exhibit evidence of hyperexcitability. Layer V pyramidal neurons were directly visualized in brain slices with infrared differential-interference contrast microscopy and evaluated with cellular electrophysiological techniques. There were no significant differences in intrinsic membrane properties and action potential shape between Kcnal-null and wild-type mice, consistent with previous findings in hippocampal slice recordings. However, the frequency of spontaneous post-synaptic currents was significantly higher in Kcnal-null compared to wild-type mice. The frequency of spontaneous inhibitory post-synaptic currents and miniature (action-potential-independent) inhibitory post-synaptic currents was also significantly higher in Kcnal-null compared to wild-type mice. However, the frequency of spontaneous and miniature excitatory post-synaptic currents was not different in these two groups of animals. Comparison of the amplitude and kinetics of miniature inhibitory and excitatory post-synaptic currents revealed differences in amplitude, rise time and half-width between Kcnal-null and wild-type mice. Our data indicate that the inhibitory drive onto layer V pyramidal neurons is increased in Kcnal knockout mice, either directly through an increased spontaneous release of GABA from presynaptic terminals contacting layer V pyramidal neurons, or an enhanced excitatory synaptic input to inhibitory interneurons.
Deskriptorji		EPILEPSY SEIZURES POTASSIUM CHANNELS PYRAMIDAL CELLS CEREBRAL CORTEX MICE, KNOCKOUT ELECTROENCEPHALOGRAPHY PATCH-CLAMP TECHNIQUES