Kinetic properties of the sodium current in periglomerular (PG) cells were investigated by applying whole-cell patch-clamp techniques to thin slices of the frog olfactory bulb. Eight of the cells were intracellularly stained with Lucifer Yellow for precise identification. Under current-clamp conditions PG cells showed rich spontaneous activity at rest. Na current was isolated from other current contributions by equimolar substitution of K+ with Cs+ in the intracellular solution to prevent K-currents, and 100 microM Cd2+ in the external solution to block Ca-current. Depolarisations beyond -40 mV activated a fast transient TTX-sensitive inward current. Once activated, INa declined exponentially to zero following a single exponential. The underlying conductance showed a sigmoidal activation between -40 and +30 mV, with half activation at -17.4 mV and a maximal value of 9.7 nS per neurone. The steady-state inactivation was complete at -30 mV and completely removed at -90 mV, with a midpoint at -56 mV. The activation process could be adequately described by third order kinetics, with time constants ranging from 260 microseconds at -20 mV to 70 microseconds at +50 mV.

Sodium current in periglomerular cells of frog olfactory bulb in vitro / Bardoni, Rita; P. C., Magherini; O., Belluzzi. - In: BRAIN RESEARCH. - ISSN 0006-8993. - STAMPA. - 730:1-2(1995), pp. 19-25.

Sodium current in periglomerular cells of frog olfactory bulb in vitro

BARDONI, Rita;
1995

Abstract

Kinetic properties of the sodium current in periglomerular (PG) cells were investigated by applying whole-cell patch-clamp techniques to thin slices of the frog olfactory bulb. Eight of the cells were intracellularly stained with Lucifer Yellow for precise identification. Under current-clamp conditions PG cells showed rich spontaneous activity at rest. Na current was isolated from other current contributions by equimolar substitution of K+ with Cs+ in the intracellular solution to prevent K-currents, and 100 microM Cd2+ in the external solution to block Ca-current. Depolarisations beyond -40 mV activated a fast transient TTX-sensitive inward current. Once activated, INa declined exponentially to zero following a single exponential. The underlying conductance showed a sigmoidal activation between -40 and +30 mV, with half activation at -17.4 mV and a maximal value of 9.7 nS per neurone. The steady-state inactivation was complete at -30 mV and completely removed at -90 mV, with a midpoint at -56 mV. The activation process could be adequately described by third order kinetics, with time constants ranging from 260 microseconds at -20 mV to 70 microseconds at +50 mV.
730
1-2
19
25
Sodium current in periglomerular cells of frog olfactory bulb in vitro / Bardoni, Rita; P. C., Magherini; O., Belluzzi. - In: BRAIN RESEARCH. - ISSN 0006-8993. - STAMPA. - 730:1-2(1995), pp. 19-25.
Bardoni, Rita; P. C., Magherini; O., Belluzzi
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/742680
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