Developmental upregulation of potassium current occurred during acquisition of hearing.
Membrane depolarization specifically inhibited Kv1.5 channel gene transcription.
Elevated potassium induced increased Kv3.1 mRNA levels. The effect of the block was prevented by the addition of calcium channel blockers.
Perturbations of activity in the auditory system regulated the levels of Kv1.1 and K3.1 channel proteins in the nucleus magnocellularis. However, alterations in channel proteins did not linearly predict changes in current densities.
Developmental changes in voltage-gated currents led to the class 3 pattern of AP development. Initially, hair cells fired APs. However, at late stages, hair cells responded to stimulation with graded potentials.
The appearance of the SK current coincided with their becoming responsive to acetylcholine. The transiently expressed SK channel was activated by Ca2+ influx through both Cav1.3 channels and nicotinic receptors.
During early stages of neuronal differentiation, potentiometric dye studies revealed developmentally regulated changes in RMP.
Two BK channel variants were described. One variant was preferentially expressed during embryonic development. In addition, there were quantitative changes in IK expression, that underlied the overall increase in excitability of differentiating cells.
Molecular analyses revealed developmental upregulation of rSlo transcripts but uniform expression of Kv3.1. Upregulation required depolarization and calcium and occurred at the transcriptional level.
The density of HVA calcium current increases after cell death, during the period of synapse elimination.
Mouse hair cells
Rat pituitary cell line
Rat inferior colliculus neurons, P3-30
Chick auditory system neurons, P1-2 (electrophysiology) and P5-10
Mouse cochlear inner hair cells, E14.5-P12
Levitan et al. (1995)
Liu and Kaczmarek (1998)
Mouse inner and outer hair cells, E14.5-P18
Marcotti and Kros (1999); Marcotti et al. (2003)
Marcotti et al. (2004)
Rat cortical cells, E11-22 Maric etal.
Embryonic rat telencephalic neuroepithelium, E12-21
Mienville and Barker (1996, 1997)
Rat cerebellum, E20 in vitro and P2-21 in vivo
Muller etal. (1998)
Chick motor neurons
Mynlieff and Beam (1992)
Table 2 (Continued)
VGIC molecular identity Regulation
Sodium and potassium
Sodium, calcium, and potassium
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