LOW-THRESHOLD NA- A NEW FAMILY OF RECEPTOR-OPERATED INWARD CURRENTS IN MAMMALIAN NERVE-CELLS( CURRENTS )

In the mammalian nervous system, various neurotransmitters can modulat e cell excitability by inducing slow membrane potential changes. In th e last decade, inhibition of potassium currents has been characterized as the primary mechanism by which neurones can undergo sustained depo larization. More recently (1990s), a new class of inward currents, whi ch are voltage-dependent and mainly carried by sodium ions, has been f ound to be activated by various neurotransmitter receptors in mammalia n central and peripheral neurones. Because the channels involved pass depolarizing current, are open at more negative membrane potentials th an the resting potential, and are voltage-gated and persistent, these currents are capable of producing regenerative and maintained depolari zations and play an important role in neuronal signalling. (C) 1997 El sevier Science B.V.