The membrane properties and Ca-currents of the trigeminal root ganglion cells in primary culture of the marine catfish, Plotosus, studied with whole-cell recordings.
Neurons of the trigeminal root ganglion (TRG) were isolated from the marine catfish Plotosus. Collagenase treatment and culture in L15 medium, modified for higher tonicity, were required to remove their myelin sheath. TRG neurons were spherical 15-20 microns in diameter after 1-4 days culture, although they later developed extensive neurites. The membrane properties were studied by whole-cell recording technique. The resting potential was about -63 mV. The specific membrane resistance and capacitance, 5.9 K omega.cm2 and 1.2 microF/cm2, were similar to those of mouse dorsal root ganglion (DRG). The action potential, however, was usually humped, and followed by a long afterhyperpolarization. The maximum firing rate reached only about 70 Hz. Voltage-clamp study revealed TTX-sensitive Na current and TEA-sensitive K current, and in addition, two types of Ca currents: low- and high-voltage activated (LVA and HVA). The HVA current seemed to be involved in hump formation. The LVA current was similar in kinetics to T-type current of chick DRG, and was presumably inactivated at the resting potential, which might be removed during the afterhyperpolarization.
Ogura
T
T
Department of Physiology, Teikyo University School of Medicine, Tokyo, Japan.
Obara
S
S
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D002397:Catfishes; D002478:Cells, Cultured; D008564:Membrane Potentials / Q000502:physiology; D012668:Trigeminal Ganglion / Q000166:cytology / Q000502:physiology*
D015220:Calcium Channels