Distribution of ion channels in trigeminal ganglion neuron of rat

Abstract

Dorsal root ganglia (DRG) neurons transmit various sensory information such as touch, pressure, pain and temperature from the peripheral region to the central nervous system. Similarly, a pair of trigeminal root ganglia (TRG) is responsible for the sensory inputs from the oromaxillofacial region to which the trigeminal nerve is innervated. The sensory neurons of mammalian DRG are known to express voltage-dependent ion channels: at least two types of sodium currents (INa) which are distinguished by their sensitivity to TTX (Bossu and Feltz 1984; Caffrey et al. 1992; Elliott and Elliott 1993; Fedulova et al. 1991; Kostyuk et al. 1981, McLean et al. 1988; Ogata and Tatebayashi 1993; Ogata and Tatebayashi 1992 a, b; Roy and Narahashi 1992; Schwartz et al. 1990). In addition, the distribution of these ion channels in DRG neurons, according to the size of cells and developmental stages, has been widely studied to elucidate the developmental and functional role of the each type of ion channels in the modulation of specific sensory modalities (Roy and Narahashi 1992; Schwartz et al. 1990). Voltage-activated calcium channels have been implicated in a number of important neuronal functions, including secretion of neurotransmitters and hormones (Perney et al. 1986; Hirning et al. 1988; Holz et al. 1988), generation of epileptiform discharges (Wong and Prince 1978) and activation of intracellular enzymes (Nishizuka 1984). Ca influx through voltage-activated calcium channels might also contribute to neurodegeneration associated with ischaemia (Choi 1988). For Distribution of ion channels in trigeminal ganglion neuron of rat